blender-archive/source/blender/blenkernel/intern/anim_sys.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2009 Blender Foundation, Joshua Leung
 * All rights reserved.
 */

/** \file
 * \ingroup bke
 */


#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <float.h>
#include <math.h>

#include "MEM_guardedalloc.h"

#include "BLI_utildefines.h"
#include "BLI_blenlib.h"
#include "BLI_alloca.h"
#include "BLI_dynstr.h"
#include "BLI_listbase.h"
#include "BLI_string_utils.h"
#include "BLI_math_rotation.h"
#include "BLI_math_vector.h"

#include "BLT_translation.h"

#include "DNA_anim_types.h"
#include "DNA_light_types.h"
#include "DNA_material_types.h"
#include "DNA_object_types.h"
#include "DNA_scene_types.h"
#include "DNA_screen_types.h"
#include "DNA_space_types.h"
#include "DNA_texture_types.h"
#include "DNA_world_types.h"

#include "BKE_action.h"
#include "BKE_animsys.h"
#include "BKE_context.h"
#include "BKE_fcurve.h"
#include "BKE_global.h"
#include "BKE_library.h"
#include "BKE_main.h"
#include "BKE_material.h"
#include "BKE_nla.h"
#include "BKE_report.h"
#include "BKE_texture.h"

#include "DEG_depsgraph.h"
#include "DEG_depsgraph_query.h"

#include "RNA_access.h"

#include "nla_private.h"

#include "atomic_ops.h"

#include "CLG_log.h"

static CLG_LogRef LOG = {"bke.anim_sys"};

/* ***************************************** */
/* AnimData API */

/* Getter/Setter -------------------------------------------- */

/* Check if ID can have AnimData */
bool id_type_can_have_animdata(const short id_type)
{
	/* Only some ID-blocks have this info for now */
	/* TODO: finish adding this for the other blocktypes */
	switch (id_type) {
		/* has AnimData */
		case ID_OB:
		case ID_ME: case ID_MB: case ID_CU: case ID_AR: case ID_LT:
		case ID_KE:
		case ID_PA:
		case ID_MA: case ID_TE: case ID_NT:
		case ID_LA: case ID_CA: case ID_WO:
		case ID_LS:
		case ID_LP:
		case ID_SPK:
		case ID_SCE:
		case ID_MC:
		case ID_MSK:
		case ID_GD:
		case ID_CF:
			return true;

		/* no AnimData */
		default:
			return false;
	}
}

bool id_can_have_animdata(const ID *id)
{
	/* sanity check */
	if (id == NULL)
		return false;

	return id_type_can_have_animdata(GS(id->name));
}

/* Get AnimData from the given ID-block. In order for this to work, we assume that
 * the AnimData pointer is stored immediately after the given ID-block in the struct,
 * as per IdAdtTemplate.
 */
AnimData *BKE_animdata_from_id(ID *id)
{
	/* only some ID-blocks have this info for now, so we cast the
	 * types that do to be of type IdAdtTemplate, and extract the
	 * AnimData that way
	 */
	if (id_can_have_animdata(id)) {
		IdAdtTemplate *iat = (IdAdtTemplate *)id;
		return iat->adt;
	}
	else
		return NULL;
}

/* Add AnimData to the given ID-block. In order for this to work, we assume that
 * the AnimData pointer is stored immediately after the given ID-block in the struct,
 * as per IdAdtTemplate. Also note that
 */
AnimData *BKE_animdata_add_id(ID *id)
{
	/* Only some ID-blocks have this info for now, so we cast the
	 * types that do to be of type IdAdtTemplate, and add the AnimData
	 * to it using the template
	 */
	if (id_can_have_animdata(id)) {
		IdAdtTemplate *iat = (IdAdtTemplate *)id;

		/* check if there's already AnimData, in which case, don't add */
		if (iat->adt == NULL) {
			AnimData *adt;

			/* add animdata */
			adt = iat->adt = MEM_callocN(sizeof(AnimData), "AnimData");

			/* set default settings */
			adt->act_influence = 1.0f;
		}

		return iat->adt;
	}
	else
		return NULL;
}

/* Action Setter --------------------------------------- */

/* Called when user tries to change the active action of an AnimData block (via RNA, Outliner, etc.) */
bool BKE_animdata_set_action(ReportList *reports, ID *id, bAction *act)
{
	AnimData *adt = BKE_animdata_from_id(id);
	bool ok = false;

	/* animdata validity check */
	if (adt == NULL) {
		BKE_report(reports, RPT_WARNING, "No AnimData to set action on");
		return ok;
	}

	/* active action is only editable when it is not a tweaking strip
	 * see rna_AnimData_action_editable() in rna_animation.c
	 */
	if ((adt->flag & ADT_NLA_EDIT_ON) || (adt->actstrip) || (adt->tmpact)) {
		/* cannot remove, otherwise things turn to custard */
		BKE_report(reports, RPT_ERROR, "Cannot change action, as it is still being edited in NLA");
		return ok;
	}

	/* manage usercount for current action */
	if (adt->action)
		id_us_min((ID *)adt->action);

	/* assume that AnimData's action can in fact be edited... */
	if (act) {
		/* action must have same type as owner */
		if (ELEM(act->idroot, 0, GS(id->name))) {
			/* can set */
			adt->action = act;
			id_us_plus((ID *)adt->action);
			ok = true;
		}
		else {
			/* cannot set */
			BKE_reportf(reports, RPT_ERROR,
			            "Could not set action '%s' onto ID '%s', as it does not have suitably rooted paths "
			            "for this purpose", act->id.name + 2, id->name);
			/* ok = false; */
		}
	}
	else {
		/* just clearing the action... */
		adt->action = NULL;
		ok = true;
	}

	return ok;
}

/* Freeing -------------------------------------------- */

/* Free AnimData used by the nominated ID-block, and clear ID-block's AnimData pointer */
void BKE_animdata_free(ID *id, const bool do_id_user)
{
	/* Only some ID-blocks have this info for now, so we cast the
	 * types that do to be of type IdAdtTemplate
	 */
	if (id_can_have_animdata(id)) {
		IdAdtTemplate *iat = (IdAdtTemplate *)id;
		AnimData *adt = iat->adt;

		/* check if there's any AnimData to start with */
		if (adt) {
			if (do_id_user) {
				/* unlink action (don't free, as it's in its own list) */
				if (adt->action)
					id_us_min(&adt->action->id);
				/* same goes for the temporarily displaced action */
				if (adt->tmpact)
					id_us_min(&adt->tmpact->id);
			}

			/* free nla data */
			BKE_nla_tracks_free(&adt->nla_tracks, do_id_user);

			/* free drivers - stored as a list of F-Curves */
			free_fcurves(&adt->drivers);

			/* free driver array cache */
			MEM_SAFE_FREE(adt->driver_array);

			/* free overrides */
			/* TODO... */

			/* free animdata now */
			MEM_freeN(adt);
			iat->adt = NULL;
		}
	}
}

/* Copying -------------------------------------------- */

/**
 * Make a copy of the given AnimData - to be used when copying datablocks.
 * \param flag: Control ID pointers management, see LIB_ID_CREATE_.../LIB_ID_COPY_... flags in BKE_library.h
 * \return The copied animdata.
 */
AnimData *BKE_animdata_copy(Main *bmain, AnimData *adt, const int flag)
{
	AnimData *dadt;

	const bool do_action = (flag & LIB_ID_COPY_ACTIONS) != 0 && (flag & LIB_ID_CREATE_NO_MAIN) == 0;
	const bool do_id_user = (flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0;

	/* sanity check before duplicating struct */
	if (adt == NULL)
		return NULL;
	dadt = MEM_dupallocN(adt);

	/* make a copy of action - at worst, user has to delete copies... */
	if (do_action) {
		BLI_assert(bmain != NULL);
		BKE_id_copy(bmain, (ID *)dadt->action, (ID **)&dadt->action);
		BKE_id_copy(bmain, (ID *)dadt->tmpact, (ID **)&dadt->tmpact);
	}
	else if (do_id_user) {
		id_us_plus((ID *)dadt->action);
		id_us_plus((ID *)dadt->tmpact);
	}

	/* duplicate NLA data */
	BKE_nla_tracks_copy(bmain, &dadt->nla_tracks, &adt->nla_tracks, flag);

	/* duplicate drivers (F-Curves) */
	copy_fcurves(&dadt->drivers, &adt->drivers);
	dadt->driver_array = NULL;

	/* don't copy overrides */
	BLI_listbase_clear(&dadt->overrides);

	/* return */
	return dadt;
}

/**
 * \param flag: Control ID pointers management, see LIB_ID_CREATE_.../LIB_ID_COPY_... flags in BKE_library.h
 * \return true is succesfully copied.
 */
bool BKE_animdata_copy_id(Main *bmain, ID *id_to, ID *id_from, const int flag)
{
	AnimData *adt;

	if ((id_to && id_from) && (GS(id_to->name) != GS(id_from->name)))
		return false;

	BKE_animdata_free(id_to, (flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0);

	adt = BKE_animdata_from_id(id_from);
	if (adt) {
		IdAdtTemplate *iat = (IdAdtTemplate *)id_to;
		iat->adt = BKE_animdata_copy(bmain, adt, flag);
	}

	return true;
}

void BKE_animdata_copy_id_action(Main *bmain, ID *id, const bool set_newid)
{
	AnimData *adt = BKE_animdata_from_id(id);
	if (adt) {
		if (adt->action) {
			id_us_min((ID *)adt->action);
			adt->action = set_newid ? ID_NEW_SET(adt->action, BKE_action_copy(bmain, adt->action)) :
			                          BKE_action_copy(bmain, adt->action);
		}
		if (adt->tmpact) {
			id_us_min((ID *)adt->tmpact);
			adt->tmpact = set_newid ? ID_NEW_SET(adt->tmpact, BKE_action_copy(bmain, adt->tmpact)) :
			                          BKE_action_copy(bmain, adt->tmpact);
		}
	}
}

/* Merge copies of the data from the src AnimData into the destination AnimData */
void BKE_animdata_merge_copy(
        Main *bmain, ID *dst_id, ID *src_id,
        eAnimData_MergeCopy_Modes action_mode, bool fix_drivers)
{
	AnimData *src = BKE_animdata_from_id(src_id);
	AnimData *dst = BKE_animdata_from_id(dst_id);

	/* sanity checks */
	if (ELEM(NULL, dst, src))
		return;

	// TODO: we must unset all "tweakmode" flags
	if ((src->flag & ADT_NLA_EDIT_ON) || (dst->flag & ADT_NLA_EDIT_ON)) {
		CLOG_ERROR(&LOG, "Merging AnimData blocks while editing NLA is dangerous as it may cause data corruption");
		return;
	}

	/* handle actions... */
	if (action_mode == ADT_MERGECOPY_SRC_COPY) {
		/* make a copy of the actions */
		dst->action = BKE_action_copy(bmain, src->action);
		dst->tmpact = BKE_action_copy(bmain, src->tmpact);
	}
	else if (action_mode == ADT_MERGECOPY_SRC_REF) {
		/* make a reference to it */
		dst->action = src->action;
		id_us_plus((ID *)dst->action);

		dst->tmpact = src->tmpact;
		id_us_plus((ID *)dst->tmpact);
	}

	/* duplicate NLA data */
	if (src->nla_tracks.first) {
		ListBase tracks = {NULL, NULL};

		BKE_nla_tracks_copy(bmain, &tracks, &src->nla_tracks, 0);
		BLI_movelisttolist(&dst->nla_tracks, &tracks);
	}

	/* duplicate drivers (F-Curves) */
	if (src->drivers.first) {
		ListBase drivers = {NULL, NULL};

		copy_fcurves(&drivers, &src->drivers);

		/* Fix up all driver targets using the old target id
		 * - This assumes that the src ID is being merged into the dst ID
		 */
		if (fix_drivers) {
			FCurve *fcu;

			for (fcu = drivers.first; fcu; fcu = fcu->next) {
				ChannelDriver *driver = fcu->driver;
				DriverVar *dvar;

				for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
					DRIVER_TARGETS_USED_LOOPER_BEGIN(dvar)
					{
						if (dtar->id == src_id) {
							dtar->id = dst_id;
						}
					}
					DRIVER_TARGETS_LOOPER_END;
				}
			}
		}

		BLI_movelisttolist(&dst->drivers, &drivers);
	}
}

/* Sub-ID Regrouping ------------------------------------------- */

/**
 * Helper heuristic for determining if a path is compatible with the basepath
 *
 * \param path: Full RNA-path from some data (usually an F-Curve) to compare
 * \param basepath: Shorter path fragment to look for
 * \return Whether there is a match
 */
static bool animpath_matches_basepath(const char path[], const char basepath[])
{
	/* we need start of path to be basepath */
	return (path && basepath) && STRPREFIX(path, basepath);
}

/* Move F-Curves in src action to dst action, setting up all the necessary groups
 * for this to happen, but only if the F-Curves being moved have the appropriate
 * "base path".
 * - This is used when data moves from one datablock to another, causing the
 *   F-Curves to need to be moved over too
 */
void action_move_fcurves_by_basepath(bAction *srcAct, bAction *dstAct, const char basepath[])
{
	FCurve *fcu, *fcn = NULL;

	/* sanity checks */
	if (ELEM(NULL, srcAct, dstAct, basepath)) {
		if (G.debug & G_DEBUG) {
			CLOG_ERROR(&LOG, "srcAct: %p, dstAct: %p, basepath: %p has insufficient info to work with",
			           (void *)srcAct, (void *)dstAct, (void *)basepath);
		}
		return;
	}

	/* clear 'temp' flags on all groups in src, as we'll be needing them later
	 * to identify groups that we've managed to empty out here
	 */
	action_groups_clear_tempflags(srcAct);

	/* iterate over all src F-Curves, moving over the ones that need to be moved */
	for (fcu = srcAct->curves.first; fcu; fcu = fcn) {
		/* store next pointer in case we move stuff */
		fcn = fcu->next;

		/* should F-Curve be moved over?
		 * - we only need the start of the path to match basepath
		 */
		if (animpath_matches_basepath(fcu->rna_path, basepath)) {
			bActionGroup *agrp = NULL;

			/* if grouped... */
			if (fcu->grp) {
				/* make sure there will be a matching group on the other side for the migrants */
				agrp = BKE_action_group_find_name(dstAct, fcu->grp->name);

				if (agrp == NULL) {
					/* add a new one with a similar name (usually will be the same though) */
					agrp = action_groups_add_new(dstAct, fcu->grp->name);
				}

				/* old groups should be tagged with 'temp' flags so they can be removed later
				 * if we remove everything from them
				 */
				fcu->grp->flag |= AGRP_TEMP;
			}

			/* perform the migration now */
			action_groups_remove_channel(srcAct, fcu);

			if (agrp)
				action_groups_add_channel(dstAct, agrp, fcu);
			else
				BLI_addtail(&dstAct->curves, fcu);
		}
	}

	/* cleanup groups (if present) */
	if (srcAct->groups.first) {
		bActionGroup *agrp, *grp = NULL;

		for (agrp = srcAct->groups.first; agrp; agrp = grp) {
			grp = agrp->next;

			/* only tagged groups need to be considered - clearing these tags or removing them */
			if (agrp->flag & AGRP_TEMP) {
				/* if group is empty and tagged, then we can remove as this operation
				 * moved out all the channels that were formerly here
				 */
				if (BLI_listbase_is_empty(&agrp->channels))
					BLI_freelinkN(&srcAct->groups, agrp);
				else
					agrp->flag &= ~AGRP_TEMP;
			}
		}
	}
}

/* Transfer the animation data from srcID to dstID where the srcID
 * animation data is based off "basepath", creating new AnimData and
 * associated data as necessary
 */
void BKE_animdata_separate_by_basepath(
        Main *bmain, ID *srcID, ID *dstID, ListBase *basepaths)
{
	AnimData *srcAdt = NULL, *dstAdt = NULL;
	LinkData *ld;

	/* sanity checks */
	if (ELEM(NULL, srcID, dstID)) {
		if (G.debug & G_DEBUG)
			CLOG_ERROR(&LOG, "no source or destination ID to separate AnimData with");
		return;
	}

	/* get animdata from src, and create for destination (if needed) */
	srcAdt = BKE_animdata_from_id(srcID);
	dstAdt = BKE_animdata_add_id(dstID);

	if (ELEM(NULL, srcAdt, dstAdt)) {
		if (G.debug & G_DEBUG)
			CLOG_ERROR(&LOG, "no AnimData for this pair of ID's");
		return;
	}

	/* active action */
	if (srcAdt->action) {
		/* set up an action if necessary, and name it in a similar way so that it can be easily found again */
		if (dstAdt->action == NULL) {
			dstAdt->action = BKE_action_add(bmain, srcAdt->action->id.name + 2);
		}
		else if (dstAdt->action == srcAdt->action) {
			CLOG_WARN(&LOG, "Argh! Source and Destination share animation! "
			          "('%s' and '%s' both use '%s') Making new empty action",
			          srcID->name, dstID->name, srcAdt->action->id.name);

			/* TODO: review this... */
			id_us_min(&dstAdt->action->id);
			dstAdt->action = BKE_action_add(bmain, dstAdt->action->id.name + 2);
		}

		/* loop over base paths, trying to fix for each one... */
		for (ld = basepaths->first; ld; ld = ld->next) {
			const char *basepath = (const char *)ld->data;
			action_move_fcurves_by_basepath(srcAdt->action, dstAdt->action, basepath);
		}
	}

	/* drivers */
	if (srcAdt->drivers.first) {
		FCurve *fcu, *fcn = NULL;

		/* check each driver against all the base paths to see if any should go */
		for (fcu = srcAdt->drivers.first; fcu; fcu = fcn) {
			fcn = fcu->next;

			/* try each basepath in turn, but stop on the first one which works */
			for (ld = basepaths->first; ld; ld = ld->next) {
				const char *basepath = (const char *)ld->data;

				if (animpath_matches_basepath(fcu->rna_path, basepath)) {
					/* just need to change lists */
					BLI_remlink(&srcAdt->drivers, fcu);
					BLI_addtail(&dstAdt->drivers, fcu);

					/* TODO: add depsgraph flushing calls? */

					/* can stop now, as moved already */
					break;
				}
			}
		}
	}
}

/**
 * Temporary wrapper for driver operators for buttons to make it easier to create
 * such drivers by rerouting all paths through the active object instead so that
 * they will get picked up by the dependency system.
 *
 * \param C: Context pointer - for getting active data
 * \param[in,out] ptr RNA pointer for property's datablock. May be modified as result of path remapping.
 * \param prop: RNA definition of property to add for
 * \return MEM_alloc'd string representing the path to the property from the given #PointerRNA
 */
char *BKE_animdata_driver_path_hack(bContext *C, PointerRNA *ptr, PropertyRNA *prop, char *base_path)
{
	ID *id = (ID *)ptr->id.data;
	ScrArea *sa = CTX_wm_area(C);

	/* get standard path which may be extended */
	char *basepath = base_path ? base_path : RNA_path_from_ID_to_property(ptr, prop);
	char *path = basepath; /* in case no remapping is needed */

	/* Remapping will only be performed in the Properties Editor, as only this
	 * restricts the subspace of options to the 'active' data (a manageable state)
	 */
	/* TODO: watch out for pinned context? */
	if ((sa) && (sa->spacetype == SPACE_PROPERTIES)) {
		Object *ob = CTX_data_active_object(C);

		if (ob && id) {
			/* TODO: after material textures were removed, this function serves
			 * no purpose anymore, but could be used again so was not removed. */

			/* fix RNA pointer, as we've now changed the ID root by changing the paths */
			if (basepath != path) {
				/* rebase provided pointer so that it starts from object... */
				RNA_pointer_create(&ob->id, ptr->type, ptr->data, ptr);
			}
		}
	}

	/* the path should now have been corrected for use */
	return path;
}

/* Path Validation -------------------------------------------- */

/* Check if a given RNA Path is valid, by tracing it from the given ID, and seeing if we can resolve it */
static bool check_rna_path_is_valid(ID *owner_id, const char *path)
{
	PointerRNA id_ptr, ptr;
	PropertyRNA *prop = NULL;

	/* make initial RNA pointer to start resolving from */
	RNA_id_pointer_create(owner_id, &id_ptr);

	/* try to resolve */
	return RNA_path_resolve_property(&id_ptr, path, &ptr, &prop);
}

/* Check if some given RNA Path needs fixing - free the given path and set a new one as appropriate
 * NOTE: we assume that oldName and newName have [" "] padding around them
 */
static char *rna_path_rename_fix(ID *owner_id, const char *prefix, const char *oldName, const char *newName, char *oldpath, bool verify_paths)
{
	char *prefixPtr = strstr(oldpath, prefix);
	char *oldNamePtr = strstr(oldpath, oldName);
	int prefixLen = strlen(prefix);
	int oldNameLen = strlen(oldName);

	/* only start fixing the path if the prefix and oldName feature in the path,
	 * and prefix occurs immediately before oldName
	 */
	if ( (prefixPtr && oldNamePtr) && (prefixPtr + prefixLen == oldNamePtr) ) {
		/* if we haven't aren't able to resolve the path now, try again after fixing it */
		if (!verify_paths || check_rna_path_is_valid(owner_id, oldpath) == 0) {
			DynStr *ds = BLI_dynstr_new();
			const char *postfixPtr = oldNamePtr + oldNameLen;
			char *newPath = NULL;

			/* add the part of the string that goes up to the start of the prefix */
			if (prefixPtr > oldpath) {
				BLI_dynstr_nappend(ds, oldpath, prefixPtr - oldpath);
			}

			/* add the prefix */
			BLI_dynstr_append(ds, prefix);

			/* add the new name (complete with brackets) */
			BLI_dynstr_append(ds, newName);

			/* add the postfix */
			BLI_dynstr_append(ds, postfixPtr);

			/* create new path, and cleanup old data */
			newPath = BLI_dynstr_get_cstring(ds);
			BLI_dynstr_free(ds);

			/* check if the new path will solve our problems */
			/* TODO: will need to check whether this step really helps in practice */
			if (!verify_paths || check_rna_path_is_valid(owner_id, newPath)) {
				/* free the old path, and return the new one, since we've solved the issues */
				MEM_freeN(oldpath);
				return newPath;
			}
			else {
				/* still couldn't resolve the path... so, might as well just leave it alone */
				MEM_freeN(newPath);
			}
		}
	}

	/* the old path doesn't need to be changed */
	return oldpath;
}

/* Check RNA-Paths for a list of F-Curves */
static bool fcurves_path_rename_fix(ID *owner_id, const char *prefix, const char *oldName, const char *newName,
                                    const char *oldKey, const char *newKey, ListBase *curves, bool verify_paths)
{
	FCurve *fcu;
	bool is_changed = false;
	/* We need to check every curve. */
	for (fcu = curves->first; fcu; fcu = fcu->next) {
		if (fcu->rna_path == NULL) {
			continue;
		}
		const char *old_path = fcu->rna_path;
		/* Firstly, handle the F-Curve's own path. */
		fcu->rna_path = rna_path_rename_fix(owner_id, prefix, oldKey, newKey, fcu->rna_path, verify_paths);
		/* if path changed and the F-Curve is grouped, check if its group also needs renaming
		 * (i.e. F-Curve is first of a bone's F-Curves; hence renaming this should also trigger rename) */
		if (fcu->rna_path != old_path) {
			bActionGroup *agrp = fcu->grp;
			is_changed = true;
			if ((agrp != NULL) && STREQ(oldName, agrp->name)) {
				BLI_strncpy(agrp->name, newName, sizeof(agrp->name));
			}
		}
	}
	return is_changed;
}

/* Check RNA-Paths for a list of Drivers */
static bool drivers_path_rename_fix(ID *owner_id, ID *ref_id, const char *prefix, const char *oldName, const char *newName,
                                    const char *oldKey, const char *newKey, ListBase *curves, bool verify_paths)
{
	bool is_changed = false;
	FCurve *fcu;
	/* We need to check every curve - drivers are F-Curves too. */
	for (fcu = curves->first; fcu; fcu = fcu->next) {
		/* firstly, handle the F-Curve's own path */
		if (fcu->rna_path != NULL) {
			const char *old_rna_path = fcu->rna_path;
			fcu->rna_path = rna_path_rename_fix(owner_id, prefix, oldKey, newKey, fcu->rna_path, verify_paths);
			is_changed |= (fcu->rna_path != old_rna_path);
		}
		if (fcu->driver == NULL) {
			continue;
		}
		ChannelDriver *driver = fcu->driver;
		DriverVar *dvar;
		/* driver variables */
		for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
			/* only change the used targets, since the others will need fixing manually anyway */
			DRIVER_TARGETS_USED_LOOPER_BEGIN(dvar)
			{
				/* rename RNA path */
				if (dtar->rna_path && dtar->id) {
					const char *old_rna_path = dtar->rna_path;
					dtar->rna_path = rna_path_rename_fix(dtar->id, prefix, oldKey, newKey, dtar->rna_path, verify_paths);
					is_changed |= (dtar->rna_path != old_rna_path);
				}
				/* also fix the bone-name (if applicable) */
				if (strstr(prefix, "bones")) {
					if ( ((dtar->id) && (GS(dtar->id->name) == ID_OB) && (!ref_id || ((Object *)(dtar->id))->data == ref_id)) &&
					     (dtar->pchan_name[0]) && STREQ(oldName, dtar->pchan_name) )
					{
						is_changed = true;
						BLI_strncpy(dtar->pchan_name, newName, sizeof(dtar->pchan_name));
					}
				}
			}
			DRIVER_TARGETS_LOOPER_END;
		}
	}
	return is_changed;
}

/* Fix all RNA-Paths for Actions linked to NLA Strips */
static bool nlastrips_path_rename_fix(ID *owner_id, const char *prefix, const char *oldName, const char *newName,
                                      const char *oldKey, const char *newKey, ListBase *strips, bool verify_paths)
{
	NlaStrip *strip;
	bool is_changed = false;
	/* Recursively check strips, fixing only actions. */
	for (strip = strips->first; strip; strip = strip->next) {
		/* fix strip's action */
		if (strip->act != NULL) {
			is_changed |= fcurves_path_rename_fix(
			        owner_id, prefix, oldName, newName, oldKey, newKey, &strip->act->curves, verify_paths);
		}
		/* Ignore own F-Curves, since those are local.  */
		/* Check sub-strips (if metas) */
		is_changed |= nlastrips_path_rename_fix(
		        owner_id, prefix, oldName, newName, oldKey, newKey, &strip->strips, verify_paths);
	}
	return is_changed;
}

/* Rename Sub-ID Entities in RNA Paths ----------------------- */

/* Fix up the given RNA-Path
 *
 * This is just an external wrapper for the RNA-Path fixing function,
 * with input validity checks on top of the basic method.
 *
 * NOTE: it is assumed that the structure we're replacing is <prefix><["><name><"]>
 *       i.e. pose.bones["Bone"]
 */
char *BKE_animsys_fix_rna_path_rename(ID *owner_id, char *old_path, const char *prefix, const char *oldName,
                                      const char *newName, int oldSubscript, int newSubscript, bool verify_paths)
{
	char *oldN, *newN;
	char *result;

	/* if no action, no need to proceed */
	if (ELEM(NULL, owner_id, old_path)) {
		if (G.debug & G_DEBUG) CLOG_WARN(&LOG, "early abort");
		return old_path;
	}

	/* Name sanitation logic - copied from BKE_animdata_fix_paths_rename() */
	if ((oldName != NULL) && (newName != NULL)) {
		/* pad the names with [" "] so that only exact matches are made */
		const size_t name_old_len = strlen(oldName);
		const size_t name_new_len = strlen(newName);
		char *name_old_esc = BLI_array_alloca(name_old_esc, (name_old_len * 2) + 1);
		char *name_new_esc = BLI_array_alloca(name_new_esc, (name_new_len * 2) + 1);

		BLI_strescape(name_old_esc, oldName, (name_old_len * 2) + 1);
		BLI_strescape(name_new_esc, newName, (name_new_len * 2) + 1);
		oldN = BLI_sprintfN("[\"%s\"]", name_old_esc);
		newN = BLI_sprintfN("[\"%s\"]", name_new_esc);
	}
	else {
		oldN = BLI_sprintfN("[%d]", oldSubscript);
		newN = BLI_sprintfN("[%d]", newSubscript);
	}

	/* fix given path */
	if (G.debug & G_DEBUG) printf("%s | %s  | oldpath = %p ", oldN, newN, old_path);
	result = rna_path_rename_fix(owner_id, prefix, oldN, newN, old_path, verify_paths);
	if (G.debug & G_DEBUG) printf("path rename result = %p\n", result);

	/* free the temp names */
	MEM_freeN(oldN);
	MEM_freeN(newN);

	/* return the resulting path - may be the same path again if nothing changed */
	return result;
}

/* Fix all RNA_Paths in the given Action, relative to the given ID block
 *
 * This is just an external wrapper for the F-Curve fixing function,
 * with input validity checks on top of the basic method.
 *
 * NOTE: it is assumed that the structure we're replacing is <prefix><["><name><"]>
 *       i.e. pose.bones["Bone"]
 */
void BKE_action_fix_paths_rename(ID *owner_id, bAction *act, const char *prefix, const char *oldName,
                                 const char *newName, int oldSubscript, int newSubscript, bool verify_paths)
{
	char *oldN, *newN;

	/* if no action, no need to proceed */
	if (ELEM(NULL, owner_id, act))
		return;

	/* Name sanitation logic - copied from BKE_animdata_fix_paths_rename() */
	if ((oldName != NULL) && (newName != NULL)) {
		/* pad the names with [" "] so that only exact matches are made */
		const size_t name_old_len = strlen(oldName);
		const size_t name_new_len = strlen(newName);
		char *name_old_esc = BLI_array_alloca(name_old_esc, (name_old_len * 2) + 1);
		char *name_new_esc = BLI_array_alloca(name_new_esc, (name_new_len * 2) + 1);

		BLI_strescape(name_old_esc, oldName, (name_old_len * 2) + 1);
		BLI_strescape(name_new_esc, newName, (name_new_len * 2) + 1);
		oldN = BLI_sprintfN("[\"%s\"]", name_old_esc);
		newN = BLI_sprintfN("[\"%s\"]", name_new_esc);
	}
	else {
		oldN = BLI_sprintfN("[%d]", oldSubscript);
		newN = BLI_sprintfN("[%d]", newSubscript);
	}

	/* fix paths in action */
	fcurves_path_rename_fix(owner_id, prefix, oldName, newName, oldN, newN, &act->curves, verify_paths);

	/* free the temp names */
	MEM_freeN(oldN);
	MEM_freeN(newN);
}

/* Fix all RNA-Paths in the AnimData block used by the given ID block
 * NOTE: it is assumed that the structure we're replacing is <prefix><["><name><"]>
 *       i.e. pose.bones["Bone"]
 */
void BKE_animdata_fix_paths_rename(ID *owner_id, AnimData *adt, ID *ref_id, const char *prefix, const char *oldName,
                                   const char *newName, int oldSubscript, int newSubscript, bool verify_paths)
{
	NlaTrack *nlt;
	char *oldN, *newN;
	/* If no AnimData, no need to proceed. */
	if (ELEM(NULL, owner_id, adt)) {
		return;
	}
	bool is_self_changed = false;
	/* Name sanitation logic - shared with BKE_action_fix_paths_rename(). */
	if ((oldName != NULL) && (newName != NULL)) {
		/* Pad the names with [" "] so that only exact matches are made. */
		const size_t name_old_len = strlen(oldName);
		const size_t name_new_len = strlen(newName);
		char *name_old_esc = BLI_array_alloca(name_old_esc, (name_old_len * 2) + 1);
		char *name_new_esc = BLI_array_alloca(name_new_esc, (name_new_len * 2) + 1);

		BLI_strescape(name_old_esc, oldName, (name_old_len * 2) + 1);
		BLI_strescape(name_new_esc, newName, (name_new_len * 2) + 1);
		oldN = BLI_sprintfN("[\"%s\"]", name_old_esc);
		newN = BLI_sprintfN("[\"%s\"]", name_new_esc);
	}
	else {
		oldN = BLI_sprintfN("[%d]", oldSubscript);
		newN = BLI_sprintfN("[%d]", newSubscript);
	}
	/* Active action and temp action. */
	if (adt->action != NULL) {
		if (fcurves_path_rename_fix(owner_id, prefix, oldName, newName,
		                            oldN, newN, &adt->action->curves, verify_paths))
		{
			DEG_id_tag_update(&adt->action->id, ID_RECALC_COPY_ON_WRITE);
		}
	}
	if (adt->tmpact) {
		if (fcurves_path_rename_fix(owner_id, prefix, oldName, newName,
		                            oldN, newN, &adt->tmpact->curves, verify_paths))
		{
			DEG_id_tag_update(&adt->tmpact->id, ID_RECALC_COPY_ON_WRITE);
		}
	}
	/* Drivers - Drivers are really F-Curves */
	is_self_changed |= drivers_path_rename_fix(
	         owner_id, ref_id, prefix, oldName, newName, oldN, newN, &adt->drivers, verify_paths);
	/* NLA Data - Animation Data for Strips */
	for (nlt = adt->nla_tracks.first; nlt; nlt = nlt->next) {
		is_self_changed |= nlastrips_path_rename_fix(
		        owner_id, prefix, oldName, newName, oldN, newN, &nlt->strips, verify_paths);
	}
	/* Tag owner ID if it */
	if (is_self_changed) {
		DEG_id_tag_update(owner_id, ID_RECALC_COPY_ON_WRITE);
	}
	/* free the temp names */
	MEM_freeN(oldN);
	MEM_freeN(newN);
}

/* Remove FCurves with Prefix  -------------------------------------- */

/* Check RNA-Paths for a list of F-Curves */
static bool fcurves_path_remove_fix(const char *prefix, ListBase *curves)
{
	FCurve *fcu, *fcn;
	bool any_removed = false;
	if (!prefix) return any_removed;

	/* we need to check every curve... */
	for (fcu = curves->first; fcu; fcu = fcn) {
		fcn = fcu->next;

		if (fcu->rna_path) {
			if (STRPREFIX(fcu->rna_path, prefix)) {
				BLI_remlink(curves, fcu);
				free_fcurve(fcu);
				any_removed = true;
			}
		}
	}
	return any_removed;
}

/* Check RNA-Paths for a list of F-Curves */
static bool nlastrips_path_remove_fix(const char *prefix, ListBase *strips)
{
	NlaStrip *strip;
	bool any_removed = false;

	/* recursively check strips, fixing only actions... */
	for (strip = strips->first; strip; strip = strip->next) {
		/* fix strip's action */
		if (strip->act) {
			any_removed |= fcurves_path_remove_fix(prefix, &strip->act->curves);
		}

		/* check sub-strips (if metas) */
		any_removed |= nlastrips_path_remove_fix(prefix, &strip->strips);
	}
	return any_removed;
}

bool BKE_animdata_fix_paths_remove(ID *id, const char *prefix)
{
	/* Only some ID-blocks have this info for now, so we cast the
	 * types that do to be of type IdAdtTemplate
	 */
	if (!id_can_have_animdata(id)) {
		return false;
	}
	bool any_removed = false;
	IdAdtTemplate *iat = (IdAdtTemplate *)id;
	AnimData *adt = iat->adt;
	/* check if there's any AnimData to start with */
	if (adt) {
		/* free fcurves */
		if (adt->action != NULL) {
			any_removed |= fcurves_path_remove_fix(prefix, &adt->action->curves);
		}
		if (adt->tmpact != NULL) {
			any_removed |= fcurves_path_remove_fix(prefix, &adt->tmpact->curves);
		}
		/* free drivers - stored as a list of F-Curves */
		any_removed |= fcurves_path_remove_fix(prefix, &adt->drivers);
		/* NLA Data - Animation Data for Strips */
		for (NlaTrack *nlt = adt->nla_tracks.first; nlt; nlt = nlt->next) {
			any_removed |= nlastrips_path_remove_fix(prefix, &nlt->strips);
		}
	}
	return any_removed;
}

/* Apply Op to All FCurves in Database --------------------------- */

/* "User-Data" wrapper used by BKE_fcurves_main_cb() */
typedef struct AllFCurvesCbWrapper {
	ID_FCurve_Edit_Callback func;  /* Operation to apply on F-Curve */
	void *user_data;               /* Custom data for that operation */
} AllFCurvesCbWrapper;

/* Helper for adt_apply_all_fcurves_cb() - Apply wrapped operator to list of F-Curves */
static void fcurves_apply_cb(ID *id, ListBase *fcurves, ID_FCurve_Edit_Callback func, void *user_data)
{
	FCurve *fcu;

	for (fcu = fcurves->first; fcu; fcu = fcu->next) {
		func(id, fcu, user_data);
	}
}

/* Helper for adt_apply_all_fcurves_cb() - Recursively go through each NLA strip */
static void nlastrips_apply_all_curves_cb(ID *id, ListBase *strips, AllFCurvesCbWrapper *wrapper)
{
	NlaStrip *strip;

	for (strip = strips->first; strip; strip = strip->next) {
		/* fix strip's action */
		if (strip->act) {
			fcurves_apply_cb(id, &strip->act->curves, wrapper->func, wrapper->user_data);
		}

		/* check sub-strips (if metas) */
		nlastrips_apply_all_curves_cb(id, &strip->strips, wrapper);
	}
}

/* Helper for BKE_fcurves_main_cb() - Dispatch wrapped operator to all F-Curves */
static void adt_apply_all_fcurves_cb(ID *id, AnimData *adt, void *wrapper_data)
{
	AllFCurvesCbWrapper *wrapper = wrapper_data;
	NlaTrack *nlt;

	if (adt->action) {
		fcurves_apply_cb(id, &adt->action->curves, wrapper->func, wrapper->user_data);
	}

	if (adt->tmpact) {
		fcurves_apply_cb(id, &adt->tmpact->curves, wrapper->func, wrapper->user_data);
	}

	/* free drivers - stored as a list of F-Curves */
	fcurves_apply_cb(id, &adt->drivers, wrapper->func, wrapper->user_data);

	/* NLA Data - Animation Data for Strips */
	for (nlt = adt->nla_tracks.first; nlt; nlt = nlt->next) {
		nlastrips_apply_all_curves_cb(id, &nlt->strips, wrapper);
	}
}

void BKE_fcurves_id_cb(ID *id, ID_FCurve_Edit_Callback func, void *user_data)
{
	AnimData *adt = BKE_animdata_from_id(id);
	if (adt != NULL) {
		AllFCurvesCbWrapper wrapper = {func, user_data};
		adt_apply_all_fcurves_cb(id, adt, &wrapper);
	}
}

/* apply the given callback function on all F-Curves attached to data in main database */
void BKE_fcurves_main_cb(Main *bmain, ID_FCurve_Edit_Callback func, void *user_data)
{
	/* Wrap F-Curve operation stuff to pass to the general AnimData-level func */
	AllFCurvesCbWrapper wrapper = {func, user_data};

	/* Use the AnimData-based function so that we don't have to reimplement all that stuff */
	BKE_animdata_main_cb(bmain, adt_apply_all_fcurves_cb, &wrapper);
}


/* Whole Database Ops -------------------------------------------- */

/* apply the given callback function on all data in main database */
void BKE_animdata_main_cb(Main *bmain, ID_AnimData_Edit_Callback func, void *user_data)
{
	ID *id;

	/* standard data version */
#define ANIMDATA_IDS_CB(first) \
	for (id = first; id; id = id->next) { \
		AnimData *adt = BKE_animdata_from_id(id); \
		if (adt) func(id, adt, user_data); \
	} (void)0

	/* "embedded" nodetree cases (i.e. scene/material/texture->nodetree) */
#define ANIMDATA_NODETREE_IDS_CB(first, NtId_Type) \
	for (id = first; id; id = id->next) { \
		AnimData *adt = BKE_animdata_from_id(id); \
		NtId_Type *ntp = (NtId_Type *)id; \
		if (ntp->nodetree) { \
			AnimData *adt2 = BKE_animdata_from_id((ID *)ntp->nodetree); \
			if (adt2) func(id, adt2, user_data); \
		} \
		if (adt) func(id, adt, user_data); \
	} (void)0

	/* nodes */
	ANIMDATA_IDS_CB(bmain->nodetrees.first);

	/* textures */
	ANIMDATA_NODETREE_IDS_CB(bmain->textures.first, Tex);

	/* lights */
	ANIMDATA_NODETREE_IDS_CB(bmain->lights.first, Light);

	/* materials */
	ANIMDATA_NODETREE_IDS_CB(bmain->materials.first, Material);

	/* cameras */
	ANIMDATA_IDS_CB(bmain->cameras.first);

	/* shapekeys */
	ANIMDATA_IDS_CB(bmain->shapekeys.first);

	/* metaballs */
	ANIMDATA_IDS_CB(bmain->metaballs.first);

	/* curves */
	ANIMDATA_IDS_CB(bmain->curves.first);

	/* armatures */
	ANIMDATA_IDS_CB(bmain->armatures.first);

	/* lattices */
	ANIMDATA_IDS_CB(bmain->lattices.first);

	/* meshes */
	ANIMDATA_IDS_CB(bmain->meshes.first);

	/* particles */
	ANIMDATA_IDS_CB(bmain->particles.first);

	/* speakers */
	ANIMDATA_IDS_CB(bmain->speakers.first);

	/* movie clips */
	ANIMDATA_IDS_CB(bmain->movieclips.first);

	/* objects */
	ANIMDATA_IDS_CB(bmain->objects.first);

	/* masks */
	ANIMDATA_IDS_CB(bmain->masks.first);

	/* worlds */
	ANIMDATA_NODETREE_IDS_CB(bmain->worlds.first, World);

	/* scenes */
	ANIMDATA_NODETREE_IDS_CB(bmain->scenes.first, Scene);

	/* line styles */
	ANIMDATA_IDS_CB(bmain->linestyles.first);

	/* grease pencil */
	ANIMDATA_IDS_CB(bmain->gpencils.first);

	/* palettes */
	ANIMDATA_IDS_CB(bmain->palettes.first);

	/* cache files */
	ANIMDATA_IDS_CB(bmain->cachefiles.first);
}

/* Fix all RNA-Paths throughout the database (directly access the Global.main version)
 * NOTE: it is assumed that the structure we're replacing is <prefix><["><name><"]>
 *      i.e. pose.bones["Bone"]
 */
/* TODO: use BKE_animdata_main_cb for looping over all data  */
void BKE_animdata_fix_paths_rename_all(ID *ref_id, const char *prefix, const char *oldName, const char *newName)
{
	Main *bmain = G.main;  /* XXX UGLY! */
	ID *id;

	/* macro for less typing
	 * - whether animdata exists is checked for by the main renaming callback, though taking
	 *   this outside of the function may make things slightly faster?
	 */
#define RENAMEFIX_ANIM_IDS(first) \
	for (id = first; id; id = id->next) { \
		AnimData *adt = BKE_animdata_from_id(id); \
		BKE_animdata_fix_paths_rename(id, adt, ref_id, prefix, oldName, newName, 0, 0, 1); \
	} (void)0

	/* another version of this macro for nodetrees */
#define RENAMEFIX_ANIM_NODETREE_IDS(first, NtId_Type) \
	for (id = first; id; id = id->next) { \
		AnimData *adt = BKE_animdata_from_id(id); \
		NtId_Type *ntp = (NtId_Type *)id; \
		if (ntp->nodetree) { \
			AnimData *adt2 = BKE_animdata_from_id((ID *)ntp->nodetree); \
			BKE_animdata_fix_paths_rename((ID *)ntp->nodetree, adt2, ref_id, prefix, oldName, newName, 0, 0, 1); \
		} \
		BKE_animdata_fix_paths_rename(id, adt, ref_id, prefix, oldName, newName, 0, 0, 1); \
	} (void)0

	/* nodes */
	RENAMEFIX_ANIM_IDS(bmain->nodetrees.first);

	/* textures */
	RENAMEFIX_ANIM_NODETREE_IDS(bmain->textures.first, Tex);

	/* lights */
	RENAMEFIX_ANIM_NODETREE_IDS(bmain->lights.first, Light);

	/* materials */
	RENAMEFIX_ANIM_NODETREE_IDS(bmain->materials.first, Material);

	/* cameras */
	RENAMEFIX_ANIM_IDS(bmain->cameras.first);

	/* shapekeys */
	RENAMEFIX_ANIM_IDS(bmain->shapekeys.first);

	/* metaballs */
	RENAMEFIX_ANIM_IDS(bmain->metaballs.first);

	/* curves */
	RENAMEFIX_ANIM_IDS(bmain->curves.first);

	/* armatures */
	RENAMEFIX_ANIM_IDS(bmain->armatures.first);

	/* lattices */
	RENAMEFIX_ANIM_IDS(bmain->lattices.first);

	/* meshes */
	RENAMEFIX_ANIM_IDS(bmain->meshes.first);

	/* particles */
	RENAMEFIX_ANIM_IDS(bmain->particles.first);

	/* speakers */
	RENAMEFIX_ANIM_IDS(bmain->speakers.first);

	/* movie clips */
	RENAMEFIX_ANIM_IDS(bmain->movieclips.first);

	/* objects */
	RENAMEFIX_ANIM_IDS(bmain->objects.first);

	/* masks */
	RENAMEFIX_ANIM_IDS(bmain->masks.first);

	/* worlds */
	RENAMEFIX_ANIM_NODETREE_IDS(bmain->worlds.first, World);

	/* linestyles */
	RENAMEFIX_ANIM_IDS(bmain->linestyles.first);

	/* grease pencil */
	RENAMEFIX_ANIM_IDS(bmain->gpencils.first);

	/* cache files */
	RENAMEFIX_ANIM_IDS(bmain->cachefiles.first);

	/* scenes */
	RENAMEFIX_ANIM_NODETREE_IDS(bmain->scenes.first, Scene);
}

/* *********************************** */
/* KeyingSet API */

/* Finding Tools --------------------------- */

/* Find the first path that matches the given criteria */
/* TODO: do we want some method to perform partial matches too? */
KS_Path *BKE_keyingset_find_path(KeyingSet *ks, ID *id, const char group_name[], const char rna_path[], int array_index, int UNUSED(group_mode))
{
	KS_Path *ksp;

	/* sanity checks */
	if (ELEM(NULL, ks, rna_path, id))
		return NULL;

	/* loop over paths in the current KeyingSet, finding the first one where all settings match
	 * (i.e. the first one where none of the checks fail and equal 0)
	 */
	for (ksp = ks->paths.first; ksp; ksp = ksp->next) {
		short eq_id = 1, eq_path = 1, eq_index = 1, eq_group = 1;

		/* id */
		if (id != ksp->id)
			eq_id = 0;

		/* path */
		if ((ksp->rna_path == NULL) || !STREQ(rna_path, ksp->rna_path))
			eq_path = 0;

		/* index - need to compare whole-array setting too... */
		if (ksp->array_index != array_index)
			eq_index = 0;

		/* group */
		if (group_name) {
			/* FIXME: these checks need to be coded... for now, it's not too important though */
		}

		/* if all aspects are ok, return */
		if (eq_id && eq_path && eq_index && eq_group)
			return ksp;
	}

	/* none found */
	return NULL;
}

/* Defining Tools --------------------------- */

/* Used to create a new 'custom' KeyingSet for the user, that will be automatically added to the stack */
KeyingSet *BKE_keyingset_add(ListBase *list, const char idname[], const char name[], short flag, short keyingflag)
{
	KeyingSet *ks;

	/* allocate new KeyingSet */
	ks = MEM_callocN(sizeof(KeyingSet), "KeyingSet");

	BLI_strncpy(ks->idname, (idname) ? idname : (name) ? name     : DATA_("KeyingSet"),  sizeof(ks->idname));
	BLI_strncpy(ks->name,   (name) ? name     : (idname) ? idname : DATA_("Keying Set"), sizeof(ks->name));

	ks->flag = flag;
	ks->keyingflag = keyingflag;
	ks->keyingoverride = keyingflag; /* NOTE: assume that if one is set one way, the other should be too, so that it'll work */

	/* add KeyingSet to list */
	BLI_addtail(list, ks);

	/* Make sure KeyingSet has a unique idname */
	BLI_uniquename(list, ks, DATA_("KeyingSet"), '.', offsetof(KeyingSet, idname), sizeof(ks->idname));

	/* Make sure KeyingSet has a unique label (this helps with identification) */
	BLI_uniquename(list, ks, DATA_("Keying Set"), '.', offsetof(KeyingSet, name), sizeof(ks->name));

	/* return new KeyingSet for further editing */
	return ks;
}

/* Add a path to a KeyingSet. Nothing is returned for now...
 * Checks are performed to ensure that destination is appropriate for the KeyingSet in question
 */
KS_Path *BKE_keyingset_add_path(KeyingSet *ks, ID *id, const char group_name[], const char rna_path[], int array_index, short flag, short groupmode)
{
	KS_Path *ksp;

	/* sanity checks */
	if (ELEM(NULL, ks, rna_path)) {
		CLOG_ERROR(&LOG, "no Keying Set and/or RNA Path to add path with");
		return NULL;
	}

	/* ID is required for all types of KeyingSets */
	if (id == NULL) {
		CLOG_ERROR(&LOG, "No ID provided for Keying Set Path");
		return NULL;
	}

	/* don't add if there is already a matching KS_Path in the KeyingSet */
	if (BKE_keyingset_find_path(ks, id, group_name, rna_path, array_index, groupmode)) {
		if (G.debug & G_DEBUG)
			CLOG_ERROR(&LOG, "destination already exists in Keying Set");
		return NULL;
	}

	/* allocate a new KeyingSet Path */
	ksp = MEM_callocN(sizeof(KS_Path), "KeyingSet Path");

	/* just store absolute info */
	ksp->id = id;
	if (group_name)
		BLI_strncpy(ksp->group, group_name, sizeof(ksp->group));
	else
		ksp->group[0] = '\0';

	/* store additional info for relative paths (just in case user makes the set relative) */
	if (id)
		ksp->idtype = GS(id->name);

	/* just copy path info */
	/* TODO: should array index be checked too? */
	ksp->rna_path = BLI_strdup(rna_path);
	ksp->array_index = array_index;

	/* store flags */
	ksp->flag = flag;
	ksp->groupmode = groupmode;

	/* add KeyingSet path to KeyingSet */
	BLI_addtail(&ks->paths, ksp);

	/* return this path */
	return ksp;
}

/* Free the given Keying Set path */
void BKE_keyingset_free_path(KeyingSet *ks, KS_Path *ksp)
{
	/* sanity check */
	if (ELEM(NULL, ks, ksp))
		return;

	/* free RNA-path info */
	if (ksp->rna_path)
		MEM_freeN(ksp->rna_path);

	/* free path itself */
	BLI_freelinkN(&ks->paths, ksp);
}

/* Copy all KeyingSets in the given list */
void BKE_keyingsets_copy(ListBase *newlist, const ListBase *list)
{
	KeyingSet *ksn;
	KS_Path *kspn;

	BLI_duplicatelist(newlist, list);

	for (ksn = newlist->first; ksn; ksn = ksn->next) {
		BLI_duplicatelist(&ksn->paths, &ksn->paths);

		for (kspn = ksn->paths.first; kspn; kspn = kspn->next)
			kspn->rna_path = MEM_dupallocN(kspn->rna_path);
	}
}

/* Freeing Tools --------------------------- */

/* Free data for KeyingSet but not set itself */
void BKE_keyingset_free(KeyingSet *ks)
{
	KS_Path *ksp, *kspn;

	/* sanity check */
	if (ks == NULL)
		return;

	/* free each path as we go to avoid looping twice */
	for (ksp = ks->paths.first; ksp; ksp = kspn) {
		kspn = ksp->next;
		BKE_keyingset_free_path(ks, ksp);
	}
}

/* Free all the KeyingSets in the given list */
void BKE_keyingsets_free(ListBase *list)
{
	KeyingSet *ks, *ksn;

	/* sanity check */
	if (list == NULL)
		return;

	/* loop over KeyingSets freeing them
	 * - BKE_keyingset_free() doesn't free the set itself, but it frees its sub-data
	 */
	for (ks = list->first; ks; ks = ksn) {
		ksn = ks->next;
		BKE_keyingset_free(ks);
		BLI_freelinkN(list, ks);
	}
}

/* ***************************************** */
/* Evaluation Data-Setting Backend */

static bool animsys_store_rna_setting(
        PointerRNA *ptr,
        /* typically 'fcu->rna_path', 'fcu->array_index' */
        const char *rna_path, const int array_index,
        PathResolvedRNA *r_result)
{
	bool success = false;
	const char *path = rna_path;

	/* write value to setting */
	if (path) {
		/* get property to write to */
		if (RNA_path_resolve_property(ptr, path, &r_result->ptr, &r_result->prop)) {
			if ((ptr->id.data == NULL) || RNA_property_animateable(&r_result->ptr, r_result->prop)) {
				int array_len = RNA_property_array_length(&r_result->ptr, r_result->prop);

				if (array_len && array_index >= array_len) {
					if (G.debug & G_DEBUG) {
						CLOG_WARN(&LOG, "Animato: Invalid array index. ID = '%s',  '%s[%d]', array length is %d",
						          (ptr->id.data) ? (((ID *)ptr->id.data)->name + 2) : "<No ID>",
						          path, array_index, array_len - 1);
					}
				}
				else {
					r_result->prop_index = array_len ? array_index : -1;
					success = true;
				}
			}
		}
		else {
			/* failed to get path */
			/* XXX don't tag as failed yet though, as there are some legit situations (Action Constraint)
			 * where some channels will not exist, but shouldn't lock up Action */
			if (G.debug & G_DEBUG) {
				CLOG_WARN(&LOG, "Animato: Invalid path. ID = '%s',  '%s[%d]'",
				          (ptr->id.data) ? (((ID *)ptr->id.data)->name + 2) : "<No ID>",
				          path, array_index);
			}
		}
	}

	return success;
}


/* less than 1.0 evaluates to false, use epsilon to avoid float error */
#define ANIMSYS_FLOAT_AS_BOOL(value) ((value) > ((1.0f - FLT_EPSILON)))

static bool animsys_read_rna_setting(PathResolvedRNA *anim_rna, float *r_value)
{
	PropertyRNA *prop = anim_rna->prop;
	PointerRNA *ptr = &anim_rna->ptr;
	int array_index = anim_rna->prop_index;
	float orig_value;

	/* caller must ensure this is animatable */
	BLI_assert(RNA_property_animateable(ptr, prop) || ptr->id.data == NULL);

	switch (RNA_property_type(prop)) {
		case PROP_BOOLEAN:
		{
			if (array_index != -1) {
				const int orig_value_coerce = RNA_property_boolean_get_index(ptr, prop, array_index);
				orig_value = (float)orig_value_coerce;
			}
			else {
				const int orig_value_coerce = RNA_property_boolean_get(ptr, prop);
				orig_value = (float)orig_value_coerce;
			}
			break;
		}
		case PROP_INT:
		{
			if (array_index != -1) {
				const int orig_value_coerce = RNA_property_int_get_index(ptr, prop, array_index);
				orig_value = (float)orig_value_coerce;
			}
			else {
				const int orig_value_coerce = RNA_property_int_get(ptr, prop);
				orig_value = (float)orig_value_coerce;
			}
			break;
		}
		case PROP_FLOAT:
		{
			if (array_index != -1) {
				const float orig_value_coerce = RNA_property_float_get_index(ptr, prop, array_index);
				orig_value = (float)orig_value_coerce;
			}
			else {
				const float orig_value_coerce = RNA_property_float_get(ptr, prop);
				orig_value = (float)orig_value_coerce;
			}
			break;
		}
		case PROP_ENUM:
		{
			const int orig_value_coerce = RNA_property_enum_get(ptr, prop);
			orig_value = (float)orig_value_coerce;
			break;
		}
		default:
			/* nothing can be done here... so it is unsuccessful? */
			return false;
	}

	if (r_value != NULL) {
		*r_value = orig_value;
	}

	/* successful */
	return true;
}

/* Write the given value to a setting using RNA, and return success */
static bool animsys_write_rna_setting(PathResolvedRNA *anim_rna, const float value)
{
	PropertyRNA *prop = anim_rna->prop;
	PointerRNA *ptr = &anim_rna->ptr;
	int array_index = anim_rna->prop_index;

	/* caller must ensure this is animatable */
	BLI_assert(RNA_property_animateable(ptr, prop) || ptr->id.data == NULL);

	/* Check whether value is new. Otherwise we skip all the updates. */
	float old_value;
	if (!animsys_read_rna_setting(anim_rna, &old_value)) {
		return false;
	}
	if (old_value == value) {
		return true;
	}

	switch (RNA_property_type(prop)) {
		case PROP_BOOLEAN:
		{
			const int value_coerce = ANIMSYS_FLOAT_AS_BOOL(value);
			if (array_index != -1) {
				RNA_property_boolean_set_index(ptr, prop, array_index, value_coerce);
			}
			else {
				RNA_property_boolean_set(ptr, prop, value_coerce);
			}
			break;
		}
		case PROP_INT:
		{
			int value_coerce = (int)value;
			RNA_property_int_clamp(ptr, prop, &value_coerce);
			if (array_index != -1) {
				RNA_property_int_set_index(ptr, prop, array_index, value_coerce);
			}
			else {
				RNA_property_int_set(ptr, prop, value_coerce);
			}
			break;
		}
		case PROP_FLOAT:
		{
			float value_coerce = value;
			RNA_property_float_clamp(ptr, prop, &value_coerce);
			if (array_index != -1) {
				RNA_property_float_set_index(ptr, prop, array_index, value_coerce);
			}
			else {
				RNA_property_float_set(ptr, prop, value_coerce);
			}
			break;
		}
		case PROP_ENUM:
		{
			const int value_coerce = (int)value;
			RNA_property_enum_set(ptr, prop, value_coerce);
			break;
		}
		default:
			/* nothing can be done here... so it is unsuccessful? */
			return false;
	}

	/* successful */
	return true;
}

/* Simple replacement based data-setting of the FCurve using RNA */
bool BKE_animsys_execute_fcurve(PointerRNA *ptr, FCurve *fcu, float curval)
{
	PathResolvedRNA anim_rna;
	bool ok = false;

	if (animsys_store_rna_setting(ptr, fcu->rna_path, fcu->array_index, &anim_rna)) {
		ok = animsys_write_rna_setting(&anim_rna, curval);
	}

	/* return whether we were successful */
	return ok;
}

static void animsys_write_orig_anim_rna(
        PointerRNA *ptr,
        const char *rna_path,
        int array_index,
        float value)
{
	/* Pointer is expected to be an ID pointer, if it's not -- we are doomed.
	 *
	 * NOTE: It is possible to have animation data on NLA strip, see T57360.
	 * TODO(sergey): Find solution for those cases.
	 */
	if (ptr->id.data == NULL) {
		return;
	}
	PointerRNA orig_ptr = *ptr;
	orig_ptr.id.data = ((ID *)orig_ptr.id.data)->orig_id;
	orig_ptr.data = orig_ptr.id.data;
	PathResolvedRNA orig_anim_rna;
	/* TODO(sergey): Is there a faster way to get anim_rna of original ID? */
	if (animsys_store_rna_setting(&orig_ptr, rna_path, array_index, &orig_anim_rna)) {
		animsys_write_rna_setting(&orig_anim_rna, value);
	}
}

/* Evaluate all the F-Curves in the given list
 * This performs a set of standard checks. If extra checks are required, separate code should be used
 */
static void animsys_evaluate_fcurves(
        Depsgraph *depsgraph, PointerRNA *ptr, ListBase *list, float ctime)
{
	const bool is_active_depsgraph = DEG_is_active(depsgraph);
	/* Calculate then execute each curve. */
	for (FCurve *fcu = list->first; fcu; fcu = fcu->next) {
		/* Check if this F-Curve doesn't belong to a muted group. */
		if ((fcu->grp != NULL) && (fcu->grp->flag & AGRP_MUTED)) {
			continue;
		}
		/* Check if this curve should be skipped. */
		if ((fcu->flag & (FCURVE_MUTED | FCURVE_DISABLED))) {
			continue;
		}
		PathResolvedRNA anim_rna;
		if (animsys_store_rna_setting(ptr, fcu->rna_path, fcu->array_index, &anim_rna)) {
			const float curval = calculate_fcurve(&anim_rna, fcu, ctime);
			animsys_write_rna_setting(&anim_rna, curval);
			if (is_active_depsgraph) {
				animsys_write_orig_anim_rna(ptr, fcu->rna_path, fcu->array_index, curval);
			}
		}
	}
}

/* ***************************************** */
/* Driver Evaluation */

/* Evaluate Drivers */
static void animsys_evaluate_drivers(PointerRNA *ptr, AnimData *adt, float ctime)
{
	FCurve *fcu;

	/* drivers are stored as F-Curves, but we cannot use the standard code, as we need to check if
	 * the depsgraph requested that this driver be evaluated...
	 */
	for (fcu = adt->drivers.first; fcu; fcu = fcu->next) {
		ChannelDriver *driver = fcu->driver;
		bool ok = false;

		/* check if this driver's curve should be skipped */
		if ((fcu->flag & (FCURVE_MUTED | FCURVE_DISABLED)) == 0) {
			/* check if driver itself is tagged for recalculation */
			/* XXX driver recalc flag is not set yet by depsgraph! */
			if ((driver) && !(driver->flag & DRIVER_FLAG_INVALID)) {
				/* evaluate this using values set already in other places
				 * NOTE: for 'layering' option later on, we should check if we should remove old value before adding
				 *       new to only be done when drivers only changed */

				PathResolvedRNA anim_rna;
				if (animsys_store_rna_setting(ptr, fcu->rna_path, fcu->array_index, &anim_rna)) {
					const float curval = calculate_fcurve(&anim_rna, fcu, ctime);
					ok = animsys_write_rna_setting(&anim_rna, curval);
				}

				/* set error-flag if evaluation failed */
				if (ok == 0)
					driver->flag |= DRIVER_FLAG_INVALID;
			}
		}
	}
}

/* ***************************************** */
/* Actions Evaluation */

/* strictly not necessary for actual "evaluation", but it is a useful safety check
 * to reduce the amount of times that users end up having to "revive" wrongly-assigned
 * actions
 */
static void action_idcode_patch_check(ID *id, bAction *act)
{
	int idcode = 0;

	/* just in case */
	if (ELEM(NULL, id, act))
		return;
	else
		idcode = GS(id->name);

	/* the actual checks... hopefully not too much of a performance hit in the long run... */
	if (act->idroot == 0) {
		/* use the current root if not set already (i.e. newly created actions and actions from 2.50-2.57 builds)
		 * - this has problems if there are 2 users, and the first one encountered is the invalid one
		 *   in which case, the user will need to manually fix this (?)
		 */
		act->idroot = idcode;
	}
	else if (act->idroot != idcode) {
		/* only report this error if debug mode is enabled (to save performance everywhere else) */
		if (G.debug & G_DEBUG) {
			printf("AnimSys Safety Check Failed: Action '%s' is not meant to be used from ID-Blocks of type %d such as '%s'\n",
			       act->id.name + 2, idcode, id->name);
		}
	}
}

/* ----------------------------------------- */

/* Evaluate Action Group */
void animsys_evaluate_action_group(PointerRNA *ptr, bAction *act, bActionGroup *agrp, float ctime)
{
	FCurve *fcu;

	/* check if mapper is appropriate for use here (we set to NULL if it's inappropriate) */
	if (ELEM(NULL, act, agrp)) return;

	action_idcode_patch_check(ptr->id.data, act);

	/* if group is muted, don't evaluated any of the F-Curve */
	if (agrp->flag & AGRP_MUTED)
		return;

	/* calculate then execute each curve */
	for (fcu = agrp->channels.first; (fcu) && (fcu->grp == agrp); fcu = fcu->next) {
		/* check if this curve should be skipped */
		if ((fcu->flag & (FCURVE_MUTED | FCURVE_DISABLED)) == 0) {
			PathResolvedRNA anim_rna;
			if (animsys_store_rna_setting(ptr, fcu->rna_path, fcu->array_index, &anim_rna)) {
				const float curval = calculate_fcurve(&anim_rna, fcu, ctime);
				animsys_write_rna_setting(&anim_rna, curval);
			}
		}
	}
}

/* Evaluate Action (F-Curve Bag) */
static void animsys_evaluate_action_ex(
        Depsgraph *depsgraph, PointerRNA *ptr, bAction *act, float ctime)
{
	/* check if mapper is appropriate for use here (we set to NULL if it's inappropriate) */
	if (act == NULL) return;

	action_idcode_patch_check(ptr->id.data, act);

	/* calculate then execute each curve */
	animsys_evaluate_fcurves(depsgraph, ptr, &act->curves, ctime);
}

void animsys_evaluate_action(Depsgraph *depsgraph, PointerRNA *ptr, bAction *act, float ctime)
{
	animsys_evaluate_action_ex(depsgraph, ptr, act, ctime);
}

/* ***************************************** */
/* NLA System - Evaluation */

/* calculate influence of strip based for given frame based on blendin/out values */
static float nlastrip_get_influence(NlaStrip *strip, float cframe)
{
	/* sanity checks - normalize the blendin/out values? */
	strip->blendin = fabsf(strip->blendin);
	strip->blendout = fabsf(strip->blendout);

	/* result depends on where frame is in respect to blendin/out values */
	if (IS_EQF(strip->blendin, 0.0f) == false && (cframe <= (strip->start + strip->blendin))) {
		/* there is some blend-in */
		return fabsf(cframe - strip->start) / (strip->blendin);
	}
	else if (IS_EQF(strip->blendout, 0.0f) == false && (cframe >= (strip->end - strip->blendout))) {
		/* there is some blend-out */
		return fabsf(strip->end - cframe) / (strip->blendout);
	}
	else {
		/* in the middle of the strip, we should be full strength */
		return 1.0f;
	}
}

/* evaluate the evaluation time and influence for the strip, storing the results in the strip */
static void nlastrip_evaluate_controls(Depsgraph *depsgraph, NlaStrip *strip, float ctime)
{
	/* now strip's evaluate F-Curves for these settings (if applicable) */
	if (strip->fcurves.first) {
		PointerRNA strip_ptr;

		/* create RNA-pointer needed to set values */
		RNA_pointer_create(NULL, &RNA_NlaStrip, strip, &strip_ptr);

		/* execute these settings as per normal */
		animsys_evaluate_fcurves(depsgraph, &strip_ptr, &strip->fcurves, ctime);
	}

	/* analytically generate values for influence and time (if applicable)
	 * - we do this after the F-Curves have been evaluated to override the effects of those
	 *   in case the override has been turned off.
	 */
	if ((strip->flag & NLASTRIP_FLAG_USR_INFLUENCE) == 0)
		strip->influence = nlastrip_get_influence(strip, ctime);

	/* Bypass evaluation time computation if time mapping is disabled. */
	if ((strip->flag & NLASTRIP_FLAG_NO_TIME_MAP) != 0) {
		strip->strip_time = ctime;
		return;
	}

	if ((strip->flag & NLASTRIP_FLAG_USR_TIME) == 0)
		strip->strip_time = nlastrip_get_frame(strip, ctime, NLATIME_CONVERT_EVAL);

	/* if user can control the evaluation time (using F-Curves), consider the option which allows this time to be clamped
	 * to lie within extents of the action-clip, so that a steady changing rate of progress through several cycles of the clip
	 * can be achieved easily
	 */
	/* NOTE: if we add any more of these special cases, we better group them up nicely... */
	if ((strip->flag & NLASTRIP_FLAG_USR_TIME) && (strip->flag & NLASTRIP_FLAG_USR_TIME_CYCLIC))
		strip->strip_time = fmod(strip->strip_time - strip->actstart, strip->actend - strip->actstart);
}

/* gets the strip active at the current time for a list of strips for evaluation purposes */
NlaEvalStrip *nlastrips_ctime_get_strip(Depsgraph *depsgraph, ListBase *list, ListBase *strips, short index, float ctime)
{
	NlaStrip *strip, *estrip = NULL;
	NlaEvalStrip *nes;
	short side = 0;

	/* loop over strips, checking if they fall within the range */
	for (strip = strips->first; strip; strip = strip->next) {
		/* check if current time occurs within this strip  */
		if (IN_RANGE_INCL(ctime, strip->start, strip->end) || (strip->flag & NLASTRIP_FLAG_NO_TIME_MAP)) {
			/* this strip is active, so try to use it */
			estrip = strip;
			side = NES_TIME_WITHIN;
			break;
		}

		/* if time occurred before current strip... */
		if (ctime < strip->start) {
			if (strip == strips->first) {
				/* before first strip - only try to use it if it extends backwards in time too */
				if (strip->extendmode == NLASTRIP_EXTEND_HOLD)
					estrip = strip;

				/* side is 'before' regardless of whether there's a useful strip */
				side = NES_TIME_BEFORE;
			}
			else {
				/* before next strip - previous strip has ended, but next hasn't begun,
				 * so blending mode depends on whether strip is being held or not...
				 * - only occurs when no transition strip added, otherwise the transition would have
				 *   been picked up above...
				 */
				strip = strip->prev;

				if (strip->extendmode != NLASTRIP_EXTEND_NOTHING)
					estrip = strip;
				side = NES_TIME_AFTER;
			}
			break;
		}

		/* if time occurred after current strip... */
		if (ctime > strip->end) {
			/* only if this is the last strip should we do anything, and only if that is being held */
			if (strip == strips->last) {
				if (strip->extendmode != NLASTRIP_EXTEND_NOTHING)
					estrip = strip;

				side = NES_TIME_AFTER;
				break;
			}

			/* otherwise, skip... as the 'before' case will catch it more elegantly! */
		}
	}

	/* check if a valid strip was found
	 * - must not be muted (i.e. will have contribution
	 */
	if ((estrip == NULL) || (estrip->flag & NLASTRIP_FLAG_MUTED))
		return NULL;

	/* if ctime was not within the boundaries of the strip, clamp! */
	switch (side) {
		case NES_TIME_BEFORE: /* extend first frame only */
			ctime = estrip->start;
			break;
		case NES_TIME_AFTER: /* extend last frame only */
			ctime = estrip->end;
			break;
	}

	/* evaluate strip's evaluation controls
	 * - skip if no influence (i.e. same effect as muting the strip)
	 * - negative influence is not supported yet... how would that be defined?
	 */
	/* TODO: this sounds a bit hacky having a few isolated F-Curves stuck on some data it operates on... */
	nlastrip_evaluate_controls(depsgraph, estrip, ctime);
	if (estrip->influence <= 0.0f)
		return NULL;

	/* check if strip has valid data to evaluate,
	 * and/or perform any additional type-specific actions
	 */
	switch (estrip->type) {
		case NLASTRIP_TYPE_CLIP:
			/* clip must have some action to evaluate */
			if (estrip->act == NULL)
				return NULL;
			break;
		case NLASTRIP_TYPE_TRANSITION:
			/* there must be strips to transition from and to (i.e. prev and next required) */
			if (ELEM(NULL, estrip->prev, estrip->next))
				return NULL;

			/* evaluate controls for the relevant extents of the bordering strips... */
			nlastrip_evaluate_controls(depsgraph, estrip->prev, estrip->start);
			nlastrip_evaluate_controls(depsgraph, estrip->next, estrip->end);
			break;
	}

	/* add to list of strips we need to evaluate */
	nes = MEM_callocN(sizeof(NlaEvalStrip), "NlaEvalStrip");

	nes->strip = estrip;
	nes->strip_mode = side;
	nes->track_index = index;
	nes->strip_time = estrip->strip_time;

	if (list)
		BLI_addtail(list, nes);

	return nes;
}

/* ---------------------- */

/* Initialize a valid mask, allocating memory if necessary. */
static void nlavalidmask_init(NlaValidMask *mask, int bits)
{
	if (BLI_BITMAP_SIZE(bits) > sizeof(mask->buffer)) {
		mask->ptr = BLI_BITMAP_NEW(bits, "NlaValidMask");
	}
	else {
		mask->ptr = mask->buffer;
	}
}

/* Free allocated memory for the mask. */
static void nlavalidmask_free(NlaValidMask *mask)
{
	if (mask->ptr != mask->buffer) {
		MEM_freeN(mask->ptr);
	}
}

/* ---------------------- */

/* Hashing functions for NlaEvalChannelKey. */
static uint nlaevalchan_keyhash(const void *ptr)
{
	const NlaEvalChannelKey *key = ptr;
	uint hash = BLI_ghashutil_ptrhash(key->ptr.data);
	return hash ^ BLI_ghashutil_ptrhash(key->prop);
}

static bool nlaevalchan_keycmp(const void *a, const void *b)
{
	const NlaEvalChannelKey *A = a;
	const NlaEvalChannelKey *B = b;

	return ((A->ptr.data != B->ptr.data) ||
	        (A->prop != B->prop));
}

/* ---------------------- */

/* Allocate a new blending value snapshot for the channel. */
static NlaEvalChannelSnapshot *nlaevalchan_snapshot_new(NlaEvalChannel *nec)
{
	int length = nec->base_snapshot.length;

	size_t byte_size = sizeof(NlaEvalChannelSnapshot) + sizeof(float) * length;
	NlaEvalChannelSnapshot *nec_snapshot = MEM_callocN(byte_size, "NlaEvalChannelSnapshot");

	nec_snapshot->channel = nec;
	nec_snapshot->length = length;

	return nec_snapshot;
}

/* Free a channel's blending value snapshot. */
static void nlaevalchan_snapshot_free(NlaEvalChannelSnapshot *nec_snapshot)
{
	BLI_assert(!nec_snapshot->is_base);

	MEM_freeN(nec_snapshot);
}

/* Copy all data in the snapshot. */
static void nlaevalchan_snapshot_copy(NlaEvalChannelSnapshot *dst, const NlaEvalChannelSnapshot *src)
{
	BLI_assert(dst->channel == src->channel);

	memcpy(dst->values, src->values, sizeof(float) * dst->length);
}

/* ---------------------- */

/* Initialize a blending state snapshot structure. */
static void nlaeval_snapshot_init(NlaEvalSnapshot *snapshot, NlaEvalData *nlaeval, NlaEvalSnapshot *base)
{
	snapshot->base = base;
	snapshot->size = MAX2(16, nlaeval->num_channels);
	snapshot->channels = MEM_callocN(sizeof(*snapshot->channels) * snapshot->size, "NlaEvalSnapshot::channels");
}

/* Retrieve the individual channel snapshot. */
static NlaEvalChannelSnapshot *nlaeval_snapshot_get(NlaEvalSnapshot *snapshot, int index)
{
	return (index < snapshot->size) ? snapshot->channels[index] : NULL;
}

/* Ensure at least this number of slots exists. */
static void nlaeval_snapshot_ensure_size(NlaEvalSnapshot *snapshot, int size)
{
	if (size > snapshot->size) {
		snapshot->size *= 2;
		CLAMP_MIN(snapshot->size, size);
		CLAMP_MIN(snapshot->size, 16);

		size_t byte_size = sizeof(*snapshot->channels) * snapshot->size;
		snapshot->channels = MEM_recallocN_id(snapshot->channels, byte_size, "NlaEvalSnapshot::channels");
	}
}

/* Retrieve the address of a slot in the blending state snapshot for this channel (may realloc). */
static NlaEvalChannelSnapshot **nlaeval_snapshot_ensure_slot(NlaEvalSnapshot *snapshot, NlaEvalChannel *nec)
{
	nlaeval_snapshot_ensure_size(snapshot, nec->owner->num_channels);
	return &snapshot->channels[nec->index];
}

/* Retrieve the blending snapshot for the specified channel, with fallback to base. */
static NlaEvalChannelSnapshot *nlaeval_snapshot_find_channel(NlaEvalSnapshot *snapshot, NlaEvalChannel *nec)
{
	while (snapshot != NULL) {
		NlaEvalChannelSnapshot *nec_snapshot = nlaeval_snapshot_get(snapshot, nec->index);
		if (nec_snapshot != NULL) {
			return nec_snapshot;
		}
		snapshot = snapshot->base;
	}

	return &nec->base_snapshot;
}

/* Retrieve or create the channel value snapshot, copying from the other snapshot (or default values) */
static NlaEvalChannelSnapshot *nlaeval_snapshot_ensure_channel(NlaEvalSnapshot *snapshot, NlaEvalChannel *nec)
{
	NlaEvalChannelSnapshot **slot = nlaeval_snapshot_ensure_slot(snapshot, nec);

	if (*slot == NULL) {
		NlaEvalChannelSnapshot *base_snapshot, *nec_snapshot;

		nec_snapshot = nlaevalchan_snapshot_new(nec);
		base_snapshot = nlaeval_snapshot_find_channel(snapshot->base, nec);

		nlaevalchan_snapshot_copy(nec_snapshot, base_snapshot);

		*slot = nec_snapshot;
	}

	return *slot;
}

/* Free all memory owned by this blending snapshot structure. */
static void nlaeval_snapshot_free_data(NlaEvalSnapshot *snapshot)
{
	if (snapshot->channels != NULL) {
		for (int i = 0; i < snapshot->size; i++) {
			NlaEvalChannelSnapshot *nec_snapshot = snapshot->channels[i];
			if (nec_snapshot != NULL) {
				nlaevalchan_snapshot_free(nec_snapshot);
			}
		}

		MEM_freeN(snapshot->channels);
	}

	snapshot->base = NULL;
	snapshot->size = 0;
	snapshot->channels = NULL;
}

/* ---------------------- */

/* Free memory owned by this evaluation channel. */
static void nlaevalchan_free_data(NlaEvalChannel *nec)
{
	nlavalidmask_free(&nec->valid);

	if (nec->blend_snapshot != NULL) {
		nlaevalchan_snapshot_free(nec->blend_snapshot);
	}
}

/* Initialize a full NLA evaluation state structure. */
static void nlaeval_init(NlaEvalData *nlaeval)
{
	memset(nlaeval, 0, sizeof(*nlaeval));

	nlaeval->path_hash = BLI_ghash_str_new("NlaEvalData::path_hash");
	nlaeval->key_hash = BLI_ghash_new(nlaevalchan_keyhash, nlaevalchan_keycmp, "NlaEvalData::key_hash");
}

static void nlaeval_free(NlaEvalData *nlaeval)
{
	/* Delete base snapshot - its channels are part of NlaEvalChannel and shouldn't be freed. */
	MEM_SAFE_FREE(nlaeval->base_snapshot.channels);

	/* Delete result snapshot. */
	nlaeval_snapshot_free_data(&nlaeval->eval_snapshot);

	/* Delete channels. */
	for (NlaEvalChannel *nec = nlaeval->channels.first; nec; nec = nec->next) {
		nlaevalchan_free_data(nec);
	}

	BLI_freelistN(&nlaeval->channels);
	BLI_ghash_free(nlaeval->path_hash, NULL, NULL);
	BLI_ghash_free(nlaeval->key_hash, NULL, NULL);
}

/* ---------------------- */

static int nlaevalchan_validate_index(NlaEvalChannel *nec, int index)
{
	if (nec->is_array) {
		if (index >= 0 && index < nec->base_snapshot.length) {
			return index;
		}

		return -1;
	}
	else {
		return 0;
	}
}

/* Initialise default values for NlaEvalChannel from the property data. */
static void nlaevalchan_get_default_values(NlaEvalChannel *nec, float *r_values)
{
	PointerRNA *ptr = &nec->key.ptr;
	PropertyRNA *prop = nec->key.prop;
	int length = nec->base_snapshot.length;

	/* Use unit quaternion for quaternion properties. */
	if (nec->mix_mode == NEC_MIX_QUATERNION) {
		unit_qt(r_values);
		return;
	}
	/* Use all zero for Axis-Angle properties. */
	if (nec->mix_mode == NEC_MIX_AXIS_ANGLE) {
		zero_v4(r_values);
		return;
	}

	/* NOTE: while this doesn't work for all RNA properties as default values aren't in fact
	 * set properly for most of them, at least the common ones (which also happen to get used
	 * in NLA strips a lot, e.g. scale) are set correctly.
	 */
	if (RNA_property_array_check(prop)) {
		BLI_assert(length == RNA_property_array_length(ptr, prop));
		bool *tmp_bool;
		int *tmp_int;

		switch (RNA_property_type(prop)) {
			case PROP_BOOLEAN:
				tmp_bool = MEM_malloc_arrayN(sizeof(*tmp_bool), length, __func__);
				RNA_property_boolean_get_default_array(ptr, prop, tmp_bool);
				for (int i = 0; i < length; i++) {
					r_values[i] = (float)tmp_bool[i];
				}
				MEM_freeN(tmp_bool);
				break;
			case PROP_INT:
				tmp_int = MEM_malloc_arrayN(sizeof(*tmp_int), length, __func__);
				RNA_property_int_get_default_array(ptr, prop, tmp_int);
				for (int i = 0; i < length; i++) {
					r_values[i] = (float)tmp_int[i];
				}
				MEM_freeN(tmp_int);
				break;
			case PROP_FLOAT:
				RNA_property_float_get_default_array(ptr, prop, r_values);
				break;
			default:
				memset(r_values, 0, sizeof(float) * length);
		}
	}
	else {
		BLI_assert(length == 1);

		switch (RNA_property_type(prop)) {
			case PROP_BOOLEAN:
				*r_values = (float)RNA_property_boolean_get_default(ptr, prop);
				break;
			case PROP_INT:
				*r_values = (float)RNA_property_int_get_default(ptr, prop);
				break;
			case PROP_FLOAT:
				*r_values = RNA_property_float_get_default(ptr, prop);
				break;
			case PROP_ENUM:
				*r_values = (float)RNA_property_enum_get_default(ptr, prop);
				break;
			default:
				*r_values = 0.0f;
		}
	}

	/* Ensure multiplicative properties aren't reset to 0. */
	if (nec->mix_mode == NEC_MIX_MULTIPLY) {
		for (int i = 0; i < length; i++) {
			if (r_values[i] == 0.0f) {
				r_values[i] = 1.0f;
			}
		}
	}
}

static char nlaevalchan_detect_mix_mode(NlaEvalChannelKey *key, int length)
{
	PropertySubType subtype = RNA_property_subtype(key->prop);

	if (subtype == PROP_QUATERNION && length == 4) {
		return NEC_MIX_QUATERNION;
	}
	else if (subtype == PROP_AXISANGLE && length == 4) {
		return NEC_MIX_AXIS_ANGLE;
	}
	else if (RNA_property_flag(key->prop) & PROP_PROPORTIONAL) {
		return NEC_MIX_MULTIPLY;
	}
	else {
		return NEC_MIX_ADD;
	}
}

/* Verify that an appropriate NlaEvalChannel for this property exists. */
static NlaEvalChannel *nlaevalchan_verify_key(NlaEvalData *nlaeval, const char *path, NlaEvalChannelKey *key)
{
	/* Look it up in the key hash. */
	NlaEvalChannel **p_key_nec;
	NlaEvalChannelKey **p_key;
	bool found_key = BLI_ghash_ensure_p_ex(nlaeval->key_hash, key, (void ***)&p_key, (void ***)&p_key_nec);

	if (found_key) {
		return *p_key_nec;
	}

	/* Create the channel. */
	bool is_array = RNA_property_array_check(key->prop);
	int length = is_array ? RNA_property_array_length(&key->ptr, key->prop) : 1;

	NlaEvalChannel *nec = MEM_callocN(sizeof(NlaEvalChannel) + sizeof(float) * length, "NlaEvalChannel");

	/* Initialize the channel. */
	nec->rna_path = path;
	nec->key = *key;

	nec->owner = nlaeval;
	nec->index = nlaeval->num_channels++;
	nec->is_array = is_array;

	nec->mix_mode = nlaevalchan_detect_mix_mode(key, length);

	nlavalidmask_init(&nec->valid, length);

	nec->base_snapshot.channel = nec;
	nec->base_snapshot.length = length;
	nec->base_snapshot.is_base = true;

	nlaevalchan_get_default_values(nec, nec->base_snapshot.values);

	/* Store channel in data structures. */
	BLI_addtail(&nlaeval->channels, nec);

	*nlaeval_snapshot_ensure_slot(&nlaeval->base_snapshot, nec) = &nec->base_snapshot;

	*p_key_nec = nec;
	*p_key = &nec->key;

	return nec;
}

/* Verify that an appropriate NlaEvalChannel for this path exists. */
static NlaEvalChannel *nlaevalchan_verify(PointerRNA *ptr, NlaEvalData *nlaeval, const char *path)
{
	if (path == NULL) {
		return NULL;
	}

	/* Lookup the path in the path based hash. */
	NlaEvalChannel **p_path_nec;
	bool found_path = BLI_ghash_ensure_p(nlaeval->path_hash, (void *)path, (void ***)&p_path_nec);

	if (found_path) {
		return *p_path_nec;
	}

	/* Resolve the property and look it up in the key hash. */
	NlaEvalChannelKey key;

	if (!RNA_path_resolve_property(ptr, path, &key.ptr, &key.prop)) {
		/* Report failure to resolve the path. */
		if (G.debug & G_DEBUG) {
			CLOG_WARN(&LOG, "Animato: Invalid path. ID = '%s',  '%s'",
			          (ptr->id.data) ? (((ID *)ptr->id.data)->name + 2) : "<No ID>", path);
		}

		/* Cache NULL result. */
		*p_path_nec = NULL;
		return NULL;
	}

	NlaEvalChannel *nec = nlaevalchan_verify_key(nlaeval, path, &key);

	if (nec->rna_path == NULL) {
		nec->rna_path = path;
	}

	return *p_path_nec = nec;
}

/* ---------------------- */

/* accumulate the old and new values of a channel according to mode and influence */
static float nla_blend_value(int blendmode, float old_value, float value, float inf)
{
	/* optimisation: no need to try applying if there is no influence */
	if (IS_EQF(inf, 0.0f)) {
		return old_value;
	}

	/* perform blending */
	switch (blendmode) {
		case NLASTRIP_MODE_ADD:
			/* simply add the scaled value on to the stack */
			return old_value + (value * inf);

		case NLASTRIP_MODE_SUBTRACT:
			/* simply subtract the scaled value from the stack */
			return old_value - (value * inf);

		case NLASTRIP_MODE_MULTIPLY:
			/* multiply the scaled value with the stack */
			/* Formula Used:
			 *     result = fac * (a * b) + (1 - fac) * a
			 */
			return inf * (old_value * value)  +   (1 - inf) * old_value;

		case NLASTRIP_MODE_COMBINE:
			BLI_assert(!"combine mode");
			ATTR_FALLTHROUGH;

		case NLASTRIP_MODE_REPLACE:
		default: /* TODO: do we really want to blend by default? it seems more uses might prefer add... */
			/* do linear interpolation
			 * - the influence of the accumulated data (elsewhere, that is called dstweight)
			 *   is 1 - influence, since the strip's influence is srcweight
			 */
			return old_value * (1.0f - inf)   +   (value * inf);
	}
}

/* accumulate the old and new values of a channel according to mode and influence */
static float nla_combine_value(int mix_mode, float base_value, float old_value, float value, float inf)
{
	/* optimisation: no need to try applying if there is no influence */
	if (IS_EQF(inf, 0.0f)) {
		return old_value;
	}

	/* perform blending */
	switch (mix_mode) {
		case NEC_MIX_ADD:
		case NEC_MIX_AXIS_ANGLE:
			return old_value + (value - base_value) * inf;

		case NEC_MIX_MULTIPLY:
			if (base_value == 0.0f) {
				base_value = 1.0f;
			}
			return old_value * powf(value / base_value, inf);

		case NEC_MIX_QUATERNION:
		default:
			BLI_assert(!"invalid mix mode");
			return old_value;
	}
}

/* compute the value that would blend to the desired target value using nla_blend_value */
static bool nla_invert_blend_value(int blend_mode, float old_value, float target_value, float influence, float *r_value)
{
	switch (blend_mode) {
		case NLASTRIP_MODE_ADD:
			*r_value = (target_value - old_value) / influence;
			return true;

		case NLASTRIP_MODE_SUBTRACT:
			*r_value = (old_value - target_value) / influence;
			return true;

		case NLASTRIP_MODE_MULTIPLY:
			if (old_value == 0.0f) {
				/* Resolve 0/0 to 1. */
				if (target_value == 0.0f) {
					*r_value = 1.0f;
					return true;
				}
				/* Division by zero. */
				return false;
			}
			else {
				*r_value = (target_value - old_value) / influence / old_value + 1.0f;
				return true;
			}

		case NLASTRIP_MODE_COMBINE:
			BLI_assert(!"combine mode");
			ATTR_FALLTHROUGH;

		case NLASTRIP_MODE_REPLACE:
		default:
			*r_value = (target_value - old_value) / influence + old_value;
			return true;
	}
}

/* compute the value that would blend to the desired target value using nla_combine_value */
static bool nla_invert_combine_value(int mix_mode, float base_value, float old_value, float target_value, float influence, float *r_value)
{
	switch (mix_mode) {
		case NEC_MIX_ADD:
		case NEC_MIX_AXIS_ANGLE:
			*r_value = base_value + (target_value - old_value) / influence;
			return true;

		case NEC_MIX_MULTIPLY:
			if (base_value == 0.0f) {
				base_value = 1.0f;
			}
			if (old_value == 0.0f) {
				/* Resolve 0/0 to 1. */
				if (target_value == 0.0f) {
					*r_value = base_value;
					return true;
				}
				/* Division by zero. */
				return false;
			}
			else {
				*r_value = base_value * powf(target_value / old_value, 1.0f / influence);
				return true;
			}

		case NEC_MIX_QUATERNION:
		default:
			BLI_assert(!"invalid mix mode");
			return false;
	}
}

/* accumulate quaternion channels for Combine mode according to influence */
static void nla_combine_quaternion(const float old_values[4], const float values[4], float influence, float result[4])
{
	float tmp_old[4], tmp_new[4];

	normalize_qt_qt(tmp_old, old_values);
	normalize_qt_qt(tmp_new, values);

	pow_qt_fl_normalized(tmp_new, influence);
	mul_qt_qtqt(result, tmp_old, tmp_new);
}

/* invert accumulation of quaternion channels for Combine mode according to influence */
static void nla_invert_combine_quaternion(const float old_values[4], const float values[4], float influence, float result[4])
{
	float tmp_old[4], tmp_new[4];

	normalize_qt_qt(tmp_old, old_values);
	normalize_qt_qt(tmp_new, values);
	invert_qt_normalized(tmp_old);

	mul_qt_qtqt(result, tmp_old, tmp_new);
	pow_qt_fl_normalized(result, 1.0f / influence);
}

/* Data about the current blend mode. */
typedef struct NlaBlendData {
	NlaEvalSnapshot *snapshot;
	int mode;
	float influence;

	NlaEvalChannel *blend_queue;
} NlaBlendData;

/* Queue the channel for deferred blending. */
static NlaEvalChannelSnapshot *nlaevalchan_queue_blend(NlaBlendData *blend, NlaEvalChannel *nec)
{
	if (!nec->in_blend) {
		if (nec->blend_snapshot == NULL) {
			nec->blend_snapshot = nlaevalchan_snapshot_new(nec);
		}

		nec->in_blend = true;
		nlaevalchan_snapshot_copy(nec->blend_snapshot, &nec->base_snapshot);

		nec->next_blend = blend->blend_queue;
		blend->blend_queue = nec;
	}

	return nec->blend_snapshot;
}

/* Accumulate (i.e. blend) the given value on to the channel it affects. */
static bool nlaeval_blend_value(NlaBlendData *blend, NlaEvalChannel *nec, int array_index, float value)
{
	if (nec == NULL) {
		return false;
	}

	int index = nlaevalchan_validate_index(nec, array_index);

	if (index < 0) {
		if (G.debug & G_DEBUG) {
			ID *id = nec->key.ptr.id.data;
			CLOG_WARN(&LOG, "Animato: Invalid array index. ID = '%s',  '%s[%d]', array length is %d",
    		          id ? (id->name + 2) : "<No ID>", nec->rna_path, array_index, nec->base_snapshot.length);
		}

		return false;
	}

	if (nec->mix_mode == NEC_MIX_QUATERNION) {
		/* For quaternion properties, always output all sub-channels. */
		BLI_bitmap_set_all(nec->valid.ptr, true, 4);
	}
	else {
		BLI_BITMAP_ENABLE(nec->valid.ptr, index);
	}

	NlaEvalChannelSnapshot *nec_snapshot = nlaeval_snapshot_ensure_channel(blend->snapshot, nec);
	float *p_value = &nec_snapshot->values[index];

	if (blend->mode == NLASTRIP_MODE_COMBINE) {
		/* Quaternion blending is deferred until all sub-channel values are known. */
		if (nec->mix_mode == NEC_MIX_QUATERNION) {
			NlaEvalChannelSnapshot *blend_snapshot = nlaevalchan_queue_blend(blend, nec);

			blend_snapshot->values[index] = value;
		}
		else {
			float base_value = nec->base_snapshot.values[index];

			*p_value = nla_combine_value(nec->mix_mode, base_value, *p_value, value, blend->influence);
		}
	}
	else {
		*p_value = nla_blend_value(blend->mode, *p_value, value, blend->influence);
	}

	return true;
}

/* Finish deferred quaternion blending. */
static void nlaeval_blend_flush(NlaBlendData *blend)
{
	NlaEvalChannel *nec;

	while ((nec = blend->blend_queue)) {
		blend->blend_queue = nec->next_blend;
		nec->in_blend = false;

		NlaEvalChannelSnapshot *nec_snapshot = nlaeval_snapshot_ensure_channel(blend->snapshot, nec);
		NlaEvalChannelSnapshot *blend_snapshot = nec->blend_snapshot;

		if (nec->mix_mode == NEC_MIX_QUATERNION) {
			nla_combine_quaternion(nec_snapshot->values, blend_snapshot->values, blend->influence, nec_snapshot->values);
		}
		else {
			BLI_assert(!"mix quaternion");
		}
	}
}

/* Blend the specified snapshots into the target, and free the input snapshots. */
static void nlaeval_snapshot_mix_and_free(NlaEvalData *nlaeval, NlaEvalSnapshot *out, NlaEvalSnapshot *in1, NlaEvalSnapshot *in2, float alpha)
{
	BLI_assert(in1->base == out && in2->base == out);

	nlaeval_snapshot_ensure_size(out, nlaeval->num_channels);

	for (int i = 0; i < nlaeval->num_channels; i++) {
		NlaEvalChannelSnapshot *c_in1 = nlaeval_snapshot_get(in1, i);
		NlaEvalChannelSnapshot *c_in2 = nlaeval_snapshot_get(in2, i);

		if (c_in1 || c_in2) {
			NlaEvalChannelSnapshot *c_out = out->channels[i];

			/* Steal the entry from one of the input snapshots. */
			if (c_out == NULL) {
				if (c_in1 != NULL) {
					c_out = c_in1;
					in1->channels[i] = NULL;
				}
				else {
					c_out = c_in2;
					in2->channels[i] = NULL;
				}
			}

			if (c_in1 == NULL) {
				c_in1 = nlaeval_snapshot_find_channel(in1->base, c_out->channel);
			}
			if (c_in2 == NULL) {
				c_in2 = nlaeval_snapshot_find_channel(in2->base, c_out->channel);
			}

			out->channels[i] = c_out;

			for (int j = 0; j < c_out->length; j++) {
				c_out->values[j] = c_in1->values[j] * (1.0f - alpha) + c_in2->values[j] * alpha;
			}
		}
	}

	nlaeval_snapshot_free_data(in1);
	nlaeval_snapshot_free_data(in2);
}

/* ---------------------- */
/* F-Modifier stack joining/separation utilities - should we generalise these for BLI_listbase.h interface? */

/* Temporarily join two lists of modifiers together, storing the result in a third list */
static void nlaeval_fmodifiers_join_stacks(ListBase *result, ListBase *list1, ListBase *list2)
{
	FModifier *fcm1, *fcm2;

	/* if list1 is invalid...  */
	if (ELEM(NULL, list1, list1->first)) {
		if (list2 && list2->first) {
			result->first = list2->first;
			result->last = list2->last;
		}
	}
	/* if list 2 is invalid... */
	else if (ELEM(NULL, list2, list2->first)) {
		result->first = list1->first;
		result->last = list1->last;
	}
	else {
		/* list1 should be added first, and list2 second, with the endpoints of these being the endpoints for result
		 * - the original lists must be left unchanged though, as we need that fact for restoring
		 */
		result->first = list1->first;
		result->last = list2->last;

		fcm1 = list1->last;
		fcm2 = list2->first;

		fcm1->next = fcm2;
		fcm2->prev = fcm1;
	}
}

/* Split two temporary lists of modifiers */
static void nlaeval_fmodifiers_split_stacks(ListBase *list1, ListBase *list2)
{
	FModifier *fcm1, *fcm2;

	/* if list1/2 is invalid... just skip */
	if (ELEM(NULL, list1, list2))
		return;
	if (ELEM(NULL, list1->first, list2->first))
		return;

	/* get endpoints */
	fcm1 = list1->last;
	fcm2 = list2->first;

	/* clear their links */
	fcm1->next = NULL;
	fcm2->prev = NULL;
}

/* ---------------------- */

/* evaluate action-clip strip */
static void nlastrip_evaluate_actionclip(PointerRNA *ptr, NlaEvalData *channels, ListBase *modifiers, NlaEvalStrip *nes, NlaEvalSnapshot *snapshot)
{
	FModifierStackStorage *storage;
	ListBase tmp_modifiers = {NULL, NULL};
	NlaStrip *strip = nes->strip;
	FCurve *fcu;
	float evaltime;

	/* sanity checks for action */
	if (strip == NULL)
		return;

	if (strip->act == NULL) {
		CLOG_ERROR(&LOG, "NLA-Strip Eval Error: Strip '%s' has no Action", strip->name);
		return;
	}

	action_idcode_patch_check(ptr->id.data, strip->act);

	/* join this strip's modifiers to the parent's modifiers (own modifiers first) */
	nlaeval_fmodifiers_join_stacks(&tmp_modifiers, &strip->modifiers, modifiers);

	/* evaluate strip's modifiers which modify time to evaluate the base curves at */
	storage = evaluate_fmodifiers_storage_new(&tmp_modifiers);
	evaltime = evaluate_time_fmodifiers(storage, &tmp_modifiers, NULL, 0.0f, strip->strip_time);

	NlaBlendData blend = {
	    .snapshot = snapshot,
	    .mode = strip->blendmode,
	    .influence = strip->influence,
	};

	/* evaluate all the F-Curves in the action, saving the relevant pointers to data that will need to be used */
	for (fcu = strip->act->curves.first; fcu; fcu = fcu->next) {
		float value = 0.0f;

		/* check if this curve should be skipped */
		if (fcu->flag & (FCURVE_MUTED | FCURVE_DISABLED))
			continue;
		if ((fcu->grp) && (fcu->grp->flag & AGRP_MUTED))
			continue;

		/* evaluate the F-Curve's value for the time given in the strip
		 * NOTE: we use the modified time here, since strip's F-Curve Modifiers are applied on top of this
		 */
		value = evaluate_fcurve(fcu, evaltime);

		/* apply strip's F-Curve Modifiers on this value
		 * NOTE: we apply the strip's original evaluation time not the modified one (as per standard F-Curve eval)
		 */
		evaluate_value_fmodifiers(storage, &tmp_modifiers, fcu, &value, strip->strip_time);

		/* get an NLA evaluation channel to work with, and accumulate the evaluated value with the value(s)
		 * stored in this channel if it has been used already
		 */
		NlaEvalChannel *nec = nlaevalchan_verify(ptr, channels, fcu->rna_path);

		nlaeval_blend_value(&blend, nec, fcu->array_index, value);
	}

	nlaeval_blend_flush(&blend);

	/* free temporary storage */
	evaluate_fmodifiers_storage_free(storage);

	/* unlink this strip's modifiers from the parent's modifiers again */
	nlaeval_fmodifiers_split_stacks(&strip->modifiers, modifiers);
}

/* evaluate transition strip */
static void nlastrip_evaluate_transition(
        Depsgraph *depsgraph, PointerRNA *ptr, NlaEvalData *channels, ListBase *modifiers, NlaEvalStrip *nes, NlaEvalSnapshot *snapshot)
{
	ListBase tmp_modifiers = {NULL, NULL};
	NlaEvalSnapshot snapshot1, snapshot2;
	NlaEvalStrip tmp_nes;
	NlaStrip *s1, *s2;

	/* join this strip's modifiers to the parent's modifiers (own modifiers first) */
	nlaeval_fmodifiers_join_stacks(&tmp_modifiers, &nes->strip->modifiers, modifiers);

	/* get the two strips to operate on
	 * - we use the endpoints of the strips directly flanking our strip
	 *   using these as the endpoints of the transition (destination and source)
	 * - these should have already been determined to be valid...
	 * - if this strip is being played in reverse, we need to swap these endpoints
	 *   otherwise they will be interpolated wrong
	 */
	if (nes->strip->flag & NLASTRIP_FLAG_REVERSE) {
		s1 = nes->strip->next;
		s2 = nes->strip->prev;
	}
	else {
		s1 = nes->strip->prev;
		s2 = nes->strip->next;
	}

	/* prepare template for 'evaluation strip'
	 * - based on the transition strip's evaluation strip data
	 * - strip_mode is NES_TIME_TRANSITION_* based on which endpoint
	 * - strip_time is the 'normalized' (i.e. in-strip) time for evaluation,
	 *   which doubles up as an additional weighting factor for the strip influences
	 *   which allows us to appear to be 'interpolating' between the two extremes
	 */
	tmp_nes = *nes;

	/* evaluate these strips into a temp-buffer (tmp_channels) */
	/* FIXME: modifier evaluation here needs some work... */
	/* first strip */
	tmp_nes.strip_mode = NES_TIME_TRANSITION_START;
	tmp_nes.strip = s1;
	nlaeval_snapshot_init(&snapshot1, channels, snapshot);
	nlastrip_evaluate(depsgraph, ptr, channels, &tmp_modifiers, &tmp_nes, &snapshot1);

	/* second strip */
	tmp_nes.strip_mode = NES_TIME_TRANSITION_END;
	tmp_nes.strip = s2;
	nlaeval_snapshot_init(&snapshot2, channels, snapshot);
	nlastrip_evaluate(depsgraph, ptr, channels, &tmp_modifiers, &tmp_nes, &snapshot2);

	/* accumulate temp-buffer and full-buffer, using the 'real' strip */
	nlaeval_snapshot_mix_and_free(channels, snapshot, &snapshot1, &snapshot2, nes->strip_time);

	/* unlink this strip's modifiers from the parent's modifiers again */
	nlaeval_fmodifiers_split_stacks(&nes->strip->modifiers, modifiers);
}

/* evaluate meta-strip */
static void nlastrip_evaluate_meta(
        Depsgraph *depsgraph, PointerRNA *ptr, NlaEvalData *channels, ListBase *modifiers, NlaEvalStrip *nes, NlaEvalSnapshot *snapshot)
{
	ListBase tmp_modifiers = {NULL, NULL};
	NlaStrip *strip = nes->strip;
	NlaEvalStrip *tmp_nes;
	float evaltime;

	/* meta-strip was calculated normally to have some time to be evaluated at
	 * and here we 'look inside' the meta strip, treating it as a decorated window to
	 * it's child strips, which get evaluated as if they were some tracks on a strip
	 * (but with some extra modifiers to apply).
	 *
	 * NOTE: keep this in sync with animsys_evaluate_nla()
	 */

	/* join this strip's modifiers to the parent's modifiers (own modifiers first) */
	nlaeval_fmodifiers_join_stacks(&tmp_modifiers, &strip->modifiers, modifiers);

	/* find the child-strip to evaluate */
	evaltime = (nes->strip_time * (strip->end - strip->start)) + strip->start;
	tmp_nes = nlastrips_ctime_get_strip(depsgraph, NULL, &strip->strips, -1, evaltime);

	/* directly evaluate child strip into accumulation buffer...
	 * - there's no need to use a temporary buffer (as it causes issues [T40082])
	 */
	if (tmp_nes) {
		nlastrip_evaluate(depsgraph, ptr, channels, &tmp_modifiers, tmp_nes, snapshot);

		/* free temp eval-strip */
		MEM_freeN(tmp_nes);
	}

	/* unlink this strip's modifiers from the parent's modifiers again */
	nlaeval_fmodifiers_split_stacks(&strip->modifiers, modifiers);
}

/* evaluates the given evaluation strip */
void nlastrip_evaluate(Depsgraph *depsgraph, PointerRNA *ptr, NlaEvalData *channels, ListBase *modifiers, NlaEvalStrip *nes, NlaEvalSnapshot *snapshot)
{
	NlaStrip *strip = nes->strip;

	/* to prevent potential infinite recursion problems (i.e. transition strip, beside meta strip containing a transition
	 * several levels deep inside it), we tag the current strip as being evaluated, and clear this when we leave
	 */
	/* TODO: be careful with this flag, since some edit tools may be running and have set this while animplayback was running */
	if (strip->flag & NLASTRIP_FLAG_EDIT_TOUCHED)
		return;
	strip->flag |= NLASTRIP_FLAG_EDIT_TOUCHED;

	/* actions to take depend on the type of strip */
	switch (strip->type) {
		case NLASTRIP_TYPE_CLIP: /* action-clip */
			nlastrip_evaluate_actionclip(ptr, channels, modifiers, nes, snapshot);
			break;
		case NLASTRIP_TYPE_TRANSITION: /* transition */
			nlastrip_evaluate_transition(depsgraph, ptr, channels, modifiers, nes, snapshot);
			break;
		case NLASTRIP_TYPE_META: /* meta */
			nlastrip_evaluate_meta(depsgraph, ptr, channels, modifiers, nes, snapshot);
			break;

		default: /* do nothing */
			break;
	}

	/* clear temp recursion safe-check */
	strip->flag &= ~NLASTRIP_FLAG_EDIT_TOUCHED;
}

/* write the accumulated settings to */
void nladata_flush_channels(Depsgraph *depsgraph, PointerRNA *ptr, NlaEvalData *channels, NlaEvalSnapshot *snapshot)
{
	/* sanity checks */
	if (channels == NULL)
		return;

	const bool is_active_depsgraph = DEG_is_active(depsgraph);

	/* for each channel with accumulated values, write its value on the property it affects */
	for (NlaEvalChannel *nec = channels->channels.first; nec; nec = nec->next) {
		NlaEvalChannelSnapshot *nec_snapshot = nlaeval_snapshot_find_channel(snapshot, nec);

		PathResolvedRNA rna = { nec->key.ptr, nec->key.prop, -1 };

		for (int i = 0; i < nec_snapshot->length; i++) {
			if (BLI_BITMAP_TEST(nec->valid.ptr, i)) {
				float value = nec_snapshot->values[i];
				if (nec->is_array) {
					rna.prop_index = i;
				}
				animsys_write_rna_setting(&rna, value);
				if (is_active_depsgraph) {
					animsys_write_orig_anim_rna(ptr, nec->rna_path, rna.prop_index, value);
				}
			}
		}
	}
}

/* ---------------------- */

static void nla_eval_domain_action(PointerRNA *ptr, NlaEvalData *channels, bAction *act, GSet *touched_actions)
{
	if (!BLI_gset_add(touched_actions, act)) {
		return;
	}

	for (FCurve *fcu = act->curves.first; fcu; fcu = fcu->next) {
		/* check if this curve should be skipped */
		if (fcu->flag & (FCURVE_MUTED | FCURVE_DISABLED))
			continue;
		if ((fcu->grp) && (fcu->grp->flag & AGRP_MUTED))
			continue;

		NlaEvalChannel *nec = nlaevalchan_verify(ptr, channels, fcu->rna_path);

		if (nec != NULL) {
			/* For quaternion properties, enable all sub-channels. */
			if (nec->mix_mode == NEC_MIX_QUATERNION) {
				BLI_bitmap_set_all(nec->valid.ptr, true, 4);
				continue;
			}

			int idx = nlaevalchan_validate_index(nec, fcu->array_index);

			if (idx >= 0) {
				BLI_BITMAP_ENABLE(nec->valid.ptr, idx);
			}
		}
	}
}

static void nla_eval_domain_strips(PointerRNA *ptr, NlaEvalData *channels, ListBase *strips, GSet *touched_actions)
{
	for (NlaStrip *strip = strips->first; strip; strip = strip->next) {
		/* check strip's action */
		if (strip->act) {
			nla_eval_domain_action(ptr, channels, strip->act, touched_actions);
		}

		/* check sub-strips (if metas) */
		nla_eval_domain_strips(ptr, channels, &strip->strips, touched_actions);
	}
}

/**
 * Ensure that all channels touched by any of the actions in enabled tracks exist.
 * This is necessary to ensure that evaluation result depends only on current frame.
 */
static void animsys_evaluate_nla_domain(PointerRNA *ptr, NlaEvalData *channels, AnimData *adt)
{
	GSet *touched_actions = BLI_gset_ptr_new(__func__);

	if (adt->action) {
		nla_eval_domain_action(ptr, channels, adt->action, touched_actions);
	}

	/* NLA Data - Animation Data for Strips */
	for (NlaTrack *nlt = adt->nla_tracks.first; nlt; nlt = nlt->next) {
		/* solo and muting are mutually exclusive... */
		if (adt->flag & ADT_NLA_SOLO_TRACK) {
			/* skip if there is a solo track, but this isn't it */
			if ((nlt->flag & NLATRACK_SOLO) == 0)
				continue;
			/* else - mute doesn't matter */
		}
		else {
			/* no solo tracks - skip track if muted */
			if (nlt->flag & NLATRACK_MUTED)
				continue;
		}

		nla_eval_domain_strips(ptr, channels, &nlt->strips, touched_actions);
	}

	BLI_gset_free(touched_actions, NULL);
}

/* ---------------------- */

/**
 * NLA Evaluation function - values are calculated and stored in temporary "NlaEvalChannels"
 *
 * \param[out] echannels Evaluation channels with calculated values
 * \param[out] r_context If not NULL, data about the currently edited strip is stored here and excluded from value calculation.
 * \return false if NLA evaluation isn't actually applicable
 */
static bool animsys_evaluate_nla(Depsgraph *depsgraph, NlaEvalData *echannels, PointerRNA *ptr, AnimData *adt, float ctime, NlaKeyframingContext *r_context)
{
	NlaTrack *nlt;
	short track_index = 0;
	bool has_strips = false;

	ListBase estrips = {NULL, NULL};
	NlaEvalStrip *nes;
	NlaStrip dummy_strip_buf;

	/* dummy strip for active action */
	NlaStrip *dummy_strip = r_context ? &r_context->strip : &dummy_strip_buf;

	memset(dummy_strip, 0, sizeof(*dummy_strip));

	/* 1. get the stack of strips to evaluate at current time (influence calculated here) */
	for (nlt = adt->nla_tracks.first; nlt; nlt = nlt->next, track_index++) {
		/* stop here if tweaking is on and this strip is the tweaking track (it will be the first one that's 'disabled')... */
		if ((adt->flag & ADT_NLA_EDIT_ON) && (nlt->flag & NLATRACK_DISABLED))
			break;

		/* solo and muting are mutually exclusive... */
		if (adt->flag & ADT_NLA_SOLO_TRACK) {
			/* skip if there is a solo track, but this isn't it */
			if ((nlt->flag & NLATRACK_SOLO) == 0)
				continue;
			/* else - mute doesn't matter */
		}
		else {
			/* no solo tracks - skip track if muted */
			if (nlt->flag & NLATRACK_MUTED)
				continue;
		}

		/* if this track has strips (but maybe they won't be suitable), set has_strips
		 * - used for mainly for still allowing normal action evaluation...
		 */
		if (nlt->strips.first)
			has_strips = true;

		/* otherwise, get strip to evaluate for this channel */
		nes = nlastrips_ctime_get_strip(depsgraph, &estrips, &nlt->strips, track_index, ctime);
		if (nes) nes->track = nlt;
	}

	/* add 'active' Action (may be tweaking track) as last strip to evaluate in NLA stack
	 * - only do this if we're not exclusively evaluating the 'solo' NLA-track
	 * - however, if the 'solo' track houses the current 'tweaking' strip,
	 *   then we should allow this to play, otherwise nothing happens
	 */
	if ((adt->action) && ((adt->flag & ADT_NLA_SOLO_TRACK) == 0 || (adt->flag & ADT_NLA_EDIT_ON))) {
		/* if there are strips, evaluate action as per NLA rules */
		if ((has_strips) || (adt->actstrip)) {
			/* make dummy NLA strip, and add that to the stack */
			ListBase dummy_trackslist;

			dummy_trackslist.first = dummy_trackslist.last = dummy_strip;

			/* Strips with a user-defined time curve don't get properly remapped for editing
			 * at the moment, so mapping them just for display may be confusing. */
			bool is_inplace_tweak = (nlt) && !(adt->flag & ADT_NLA_EDIT_NOMAP) && !(adt->actstrip->flag & NLASTRIP_FLAG_USR_TIME);

			if (is_inplace_tweak) {
				/* edit active action in-place according to its active strip, so copy the data  */
				memcpy(dummy_strip, adt->actstrip, sizeof(NlaStrip));
				dummy_strip->next = dummy_strip->prev = NULL;
			}
			else {
				/* set settings of dummy NLA strip from AnimData settings */
				dummy_strip->act = adt->action;

				/* action range is calculated taking F-Modifiers into account (which making new strips doesn't do due to the troublesome nature of that) */
				calc_action_range(dummy_strip->act, &dummy_strip->actstart, &dummy_strip->actend, 1);
				dummy_strip->start = dummy_strip->actstart;
				dummy_strip->end = (IS_EQF(dummy_strip->actstart, dummy_strip->actend)) ?  (dummy_strip->actstart + 1.0f) : (dummy_strip->actend);

				/* Always use the blend mode of the strip in tweak mode, even if not in-place. */
				if (nlt && adt->actstrip) {
					dummy_strip->blendmode = adt->actstrip->blendmode;
					dummy_strip->extendmode = NLASTRIP_EXTEND_HOLD;
				}
				else {
					dummy_strip->blendmode = adt->act_blendmode;
					dummy_strip->extendmode = adt->act_extendmode;
				}

				/* Unless extendmode is Nothing (might be useful for flattening NLA evaluation), disable range. */
				if (dummy_strip->extendmode != NLASTRIP_EXTEND_NOTHING) {
					dummy_strip->flag |= NLASTRIP_FLAG_NO_TIME_MAP;
				}

				dummy_strip->influence = adt->act_influence;

				/* NOTE: must set this, or else the default setting overrides, and this setting doesn't work */
				dummy_strip->flag |= NLASTRIP_FLAG_USR_INFLUENCE;
			}

			/* add this to our list of evaluation strips */
			if (r_context == NULL) {
				nlastrips_ctime_get_strip(depsgraph, &estrips, &dummy_trackslist, -1, ctime);
			}
			/* If computing the context for keyframing, store data there instead of the list. */
			else {
				/* The extend mode here effectively controls whether it is possible to keyframe beyond the ends. */
				dummy_strip->extendmode = is_inplace_tweak ? NLASTRIP_EXTEND_NOTHING : NLASTRIP_EXTEND_HOLD;

				r_context->eval_strip = nes = nlastrips_ctime_get_strip(depsgraph, NULL, &dummy_trackslist, -1, ctime);

				/* These setting combinations require no data from strips below, so exit immediately. */
				if ((nes == NULL) || (dummy_strip->blendmode == NLASTRIP_MODE_REPLACE && dummy_strip->influence == 1.0f)) {
					BLI_freelistN(&estrips);
					return true;
				}
			}
		}
		else {
			/* special case - evaluate as if there isn't any NLA data */
			BLI_freelistN(&estrips);
			return false;
		}
	}

	/* only continue if there are strips to evaluate */
	if (BLI_listbase_is_empty(&estrips))
		return true;

	/* 2. for each strip, evaluate then accumulate on top of existing channels, but don't set values yet */
	for (nes = estrips.first; nes; nes = nes->next)
		nlastrip_evaluate(depsgraph, ptr, echannels, NULL, nes, &echannels->eval_snapshot);

	/* 3. free temporary evaluation data that's not used elsewhere */
	BLI_freelistN(&estrips);
	return true;
}

/* NLA Evaluation function (mostly for use through do_animdata)
 * - All channels that will be affected are not cleared anymore. Instead, we just evaluate into
 *   some temp channels, where values can be accumulated in one go.
 */
static void animsys_calculate_nla(Depsgraph *depsgraph, PointerRNA *ptr, AnimData *adt, float ctime)
{
	NlaEvalData echannels;

	nlaeval_init(&echannels);

	/* evaluate the NLA stack, obtaining a set of values to flush */
	if (animsys_evaluate_nla(depsgraph, &echannels, ptr, adt, ctime, NULL)) {
		/* reset any channels touched by currently inactive actions to default value */
		animsys_evaluate_nla_domain(ptr, &echannels, adt);

		/* flush effects of accumulating channels in NLA to the actual data they affect */
		nladata_flush_channels(depsgraph, ptr, &echannels, &echannels.eval_snapshot);
	}
	else {
		/* special case - evaluate as if there isn't any NLA data */
		/* TODO: this is really just a stop-gap measure... */
		if (G.debug & G_DEBUG) CLOG_WARN(&LOG, "NLA Eval: Stopgap for active action on NLA Stack - no strips case");

		animsys_evaluate_action(depsgraph, ptr, adt->action, ctime);
	}

	/* free temp data */
	nlaeval_free(&echannels);
}

/* ---------------------- */

/**
 * Prepare data necessary to compute correct keyframe values for NLA strips
 * with non-Replace mode or influence different from 1.
 *
 * @param cache List used to cache contexts for reuse when keying multiple channels in one operation.
 * @param ptr RNA pointer to the Object with the animation.
 * @return Keyframing context, or NULL if not necessary.
 */
NlaKeyframingContext *BKE_animsys_get_nla_keyframing_context(
        struct ListBase *cache, struct Depsgraph *depsgraph, struct PointerRNA *ptr, struct AnimData *adt, float ctime)
{
	/* No remapping needed if NLA is off or no action. */
	if ((adt == NULL) || (adt->action == NULL) || (adt->nla_tracks.first == NULL) || (adt->flag & ADT_NLA_EVAL_OFF)) {
		return NULL;
	}

	/* No remapping if editing an ordinary Replace action with full influence. */
	if (!(adt->flag & ADT_NLA_EDIT_ON) && (adt->act_blendmode == NLASTRIP_MODE_REPLACE && adt->act_influence == 1.0f)) {
		return NULL;
	}

	/* Try to find a cached context. */
	NlaKeyframingContext *ctx = BLI_findptr(cache, adt, offsetof(NlaKeyframingContext, adt));

	if (ctx == NULL) {
		/* Allocate and evaluate a new context. */
		ctx = MEM_callocN(sizeof(*ctx), "NlaKeyframingContext");
		ctx->adt = adt;

		nlaeval_init(&ctx->nla_channels);
		animsys_evaluate_nla(depsgraph, &ctx->nla_channels, ptr, adt, ctime, ctx);

		BLI_assert(ELEM(ctx->strip.act, NULL, adt->action));
		BLI_addtail(cache, ctx);
	}

	return ctx;
}

/**
 * Apply correction from the NLA context to the values about to be keyframed.
 *
 * @param context Context to use (may be NULL).
 * @param prop_ptr Property about to be keyframed.
 * @param[in,out] values Array of property values to adjust.
 * @param count Number of values in the array.
 * @param index Index of the element about to be updated, or -1.
 * @param[out] r_force_all Set to true if all channels must be inserted. May be NULL.
 * @return False if correction fails due to a division by zero, or null r_force_all when all channels are required.
 */
bool BKE_animsys_nla_remap_keyframe_values(struct NlaKeyframingContext *context, struct PointerRNA *prop_ptr, struct PropertyRNA *prop, float *values, int count, int index, bool *r_force_all)
{
	if (r_force_all != NULL) {
		*r_force_all = false;
	}

	/* No context means no correction. */
	if (context == NULL || context->strip.act == NULL) {
		return true;
	}

	/* If the strip is not evaluated, it is the same as zero influence. */
	if (context->eval_strip == NULL) {
		return false;
	}

	/* Full influence Replace strips also require no correction. */
	int blend_mode = context->strip.blendmode;
	float influence = context->strip.influence;

	if (blend_mode == NLASTRIP_MODE_REPLACE && influence == 1.0f) {
		return true;
	}

	/* Zero influence is division by zero. */
	if (influence <= 0.0f) {
		return false;
	}

	/* Find the evaluation channel for the NLA stack below current strip. */
	NlaEvalChannelKey key = { .ptr = *prop_ptr, .prop = prop, };
	NlaEvalData *nlaeval = &context->nla_channels;
	NlaEvalChannel *nec = nlaevalchan_verify_key(nlaeval, NULL, &key);

	if (nec->base_snapshot.length != count) {
		BLI_assert(!"invalid value count");
		return false;
	}

	/* Invert the blending operation to compute the desired key values. */
	NlaEvalChannelSnapshot *nec_snapshot = nlaeval_snapshot_find_channel(&nlaeval->eval_snapshot, nec);

	float *old_values = nec_snapshot->values;

	if (blend_mode == NLASTRIP_MODE_COMBINE) {
		/* Quaternion combine handles all sub-channels as a unit. */
		if (nec->mix_mode == NEC_MIX_QUATERNION) {
			if (r_force_all == NULL) {
				return false;
			}

			*r_force_all = true;

			nla_invert_combine_quaternion(old_values, values, influence, values);
		}
		else {
			float *base_values = nec->base_snapshot.values;

			for (int i = 0; i < count; i++) {
				if (ELEM(index, i, -1)) {
					if (!nla_invert_combine_value(nec->mix_mode, base_values[i], old_values[i], values[i], influence, &values[i])) {
						return false;
					}
				}
			}
		}
	}
	else {
		for (int i = 0; i < count; i++) {
			if (ELEM(index, i, -1)) {
				if (!nla_invert_blend_value(blend_mode, old_values[i], values[i], influence, &values[i])) {
					return false;
				}
			}
		}
	}

	return true;
}

/**
 * Free all cached contexts from the list.
 */
void BKE_animsys_free_nla_keyframing_context_cache(struct ListBase *cache)
{
	for (NlaKeyframingContext *ctx = cache->first; ctx; ctx = ctx->next) {
		MEM_SAFE_FREE(ctx->eval_strip);
		nlaeval_free(&ctx->nla_channels);
	}

	BLI_freelistN(cache);
}

/* ***************************************** */
/* Overrides System - Public API */

/* Evaluate Overrides */
static void animsys_evaluate_overrides(PointerRNA *ptr, AnimData *adt)
{
	AnimOverride *aor;

	/* for each override, simply execute... */
	for (aor = adt->overrides.first; aor; aor = aor->next) {
		PathResolvedRNA anim_rna;
		if (animsys_store_rna_setting(ptr, aor->rna_path, aor->array_index, &anim_rna)) {
			animsys_write_rna_setting(&anim_rna, aor->value);
		}
	}
}

/* ***************************************** */
/* Evaluation System - Public API */

/* Overview of how this system works:
 * 1) Depsgraph sorts data as necessary, so that data is in an order that means
 *     that all dependencies are resolved before dependents.
 * 2) All normal animation is evaluated, so that drivers have some basis values to
 *    work with
 *    a.  NLA stacks are done first, as the Active Actions act as 'tweaking' tracks
 *        which modify the effects of the NLA-stacks
 *    b.  Active Action is evaluated as per normal, on top of the results of the NLA tracks
 *
 * --------------< often in a separate phase... >------------------
 *
 * 3) Drivers/expressions are evaluated on top of this, in an order where dependencies are
 *    resolved nicely.
 *    Note: it may be necessary to have some tools to handle the cases where some higher-level
 *          drivers are added and cause some problematic dependencies that didn't exist in the local levels...
 *
 * --------------< always executed >------------------
 *
 * Maintenance of editability of settings (XXX):
 *  In order to ensure that settings that are animated can still be manipulated in the UI without requiring
 *  that keyframes are added to prevent these values from being overwritten, we use 'overrides'.
 *
 * Unresolved things:
 * - Handling of multi-user settings (i.e. time-offset, group-instancing) -> big cache grids or nodal system? but stored where?
 * - Multiple-block dependencies (i.e. drivers for settings are in both local and higher levels) -> split into separate lists?
 *
 * Current Status:
 * - Currently (as of September 2009), overrides we haven't needed to (fully) implement overrides.
 *   However, the code for this is relatively harmless, so is left in the code for now.
 */

/* Evaluation loop for evaluation animation data
 *
 * This assumes that the animation-data provided belongs to the ID block in question,
 * and that the flags for which parts of the anim-data settings need to be recalculated
 * have been set already by the depsgraph. Now, we use the recalc
 */
void BKE_animsys_evaluate_animdata(Depsgraph *depsgraph, Scene *scene, ID *id, AnimData *adt, float ctime, short recalc)
{
	PointerRNA id_ptr;

	/* sanity checks */
	if (ELEM(NULL, id, adt))
		return;

	/* get pointer to ID-block for RNA to use */
	RNA_id_pointer_create(id, &id_ptr);

	/* recalculate keyframe data:
	 * - NLA before Active Action, as Active Action behaves as 'tweaking track'
	 *   that overrides 'rough' work in NLA
	 */
	/* TODO: need to double check that this all works correctly */
	if (recalc & ADT_RECALC_ANIM) {
		/* evaluate NLA data */
		if ((adt->nla_tracks.first) && !(adt->flag & ADT_NLA_EVAL_OFF)) {
			/* evaluate NLA-stack
			 * - active action is evaluated as part of the NLA stack as the last item
			 */
			animsys_calculate_nla(depsgraph, &id_ptr, adt, ctime);
		}
		/* evaluate Active Action only */
		else if (adt->action)
			animsys_evaluate_action_ex(depsgraph, &id_ptr, adt->action, ctime);
	}

	/* recalculate drivers
	 * - Drivers need to be evaluated afterwards, as they can either override
	 *   or be layered on top of existing animation data.
	 * - Drivers should be in the appropriate order to be evaluated without problems...
	 */
	if (recalc & ADT_RECALC_DRIVERS) {
		animsys_evaluate_drivers(&id_ptr, adt, ctime);
	}

	/* always execute 'overrides'
	 * - Overrides allow editing, by overwriting the value(s) set from animation-data, with the
	 *   value last set by the user (and not keyframed yet).
	 * - Overrides are cleared upon frame change and/or keyframing
	 * - It is best that we execute this every time, so that no errors are likely to occur.
	 */
	animsys_evaluate_overrides(&id_ptr, adt);

	/* execute and clear all cached property update functions */
	if (scene) {
		Main *bmain = G.main; // xxx - to get passed in!
		RNA_property_update_cache_flush(bmain, scene);
		RNA_property_update_cache_free();
	}
}

/* Evaluation of all ID-blocks with Animation Data blocks - Animation Data Only
 *
 * This will evaluate only the animation info available in the animation data-blocks
 * encountered. In order to enforce the system by which some settings controlled by a
 * 'local' (i.e. belonging in the nearest ID-block that setting is related to, not a
 * standard 'root') block are overridden by a larger 'user'
 */
void BKE_animsys_evaluate_all_animation(Main *main, Depsgraph *depsgraph, Scene *scene, float ctime)
{
	ID *id;

	if (G.debug & G_DEBUG)
		printf("Evaluate all animation - %f\n", ctime);

	/* macros for less typing
	 * - only evaluate animation data for id if it has users (and not just fake ones)
	 * - whether animdata exists is checked for by the evaluation function, though taking
	 *   this outside of the function may make things slightly faster?
	 */
#define EVAL_ANIM_IDS(first, aflag) \
	for (id = first; id; id = id->next) { \
		if (ID_REAL_USERS(id) > 0) { \
			AnimData *adt = BKE_animdata_from_id(id); \
			BKE_animsys_evaluate_animdata(depsgraph, scene, id, adt, ctime, aflag); \
		} \
	} (void)0

	/* another macro for the "embedded" nodetree cases
	 * - this is like EVAL_ANIM_IDS, but this handles the case "embedded nodetrees"
	 *   (i.e. scene/material/texture->nodetree) which we need a special exception
	 *   for, otherwise they'd get skipped
	 * - ntp = "node tree parent" = datablock where node tree stuff resides
	 */
#define EVAL_ANIM_NODETREE_IDS(first, NtId_Type, aflag) \
	for (id = first; id; id = id->next) { \
		if (ID_REAL_USERS(id) > 0) { \
			AnimData *adt = BKE_animdata_from_id(id); \
			NtId_Type *ntp = (NtId_Type *)id; \
			if (ntp->nodetree) { \
				AnimData *adt2 = BKE_animdata_from_id((ID *)ntp->nodetree); \
				BKE_animsys_evaluate_animdata(depsgraph, scene, (ID *)ntp->nodetree, adt2, ctime, ADT_RECALC_ANIM); \
			} \
			BKE_animsys_evaluate_animdata(depsgraph, scene, id, adt, ctime, aflag); \
		} \
	} (void)0

	/* optimization:
	 * when there are no actions, don't go over database and loop over heaps of datablocks,
	 * which should ultimately be empty, since it is not possible for now to have any animation
	 * without some actions, and drivers wouldn't get affected by any state changes
	 *
	 * however, if there are some curves, we will need to make sure that their 'ctime' property gets
	 * set correctly, so this optimization must be skipped in that case...
	 */
	if (BLI_listbase_is_empty(&main->actions) && BLI_listbase_is_empty(&main->curves)) {
		if (G.debug & G_DEBUG)
			printf("\tNo Actions, so no animation needs to be evaluated...\n");

		return;
	}

	/* nodes */
	EVAL_ANIM_IDS(main->nodetrees.first, ADT_RECALC_ANIM);

	/* textures */
	EVAL_ANIM_NODETREE_IDS(main->textures.first, Tex, ADT_RECALC_ANIM);

	/* lights */
	EVAL_ANIM_NODETREE_IDS(main->lights.first, Light, ADT_RECALC_ANIM);

	/* materials */
	EVAL_ANIM_NODETREE_IDS(main->materials.first, Material, ADT_RECALC_ANIM);

	/* cameras */
	EVAL_ANIM_IDS(main->cameras.first, ADT_RECALC_ANIM);

	/* shapekeys */
	EVAL_ANIM_IDS(main->shapekeys.first, ADT_RECALC_ANIM);

	/* metaballs */
	EVAL_ANIM_IDS(main->metaballs.first, ADT_RECALC_ANIM);

	/* curves */
	EVAL_ANIM_IDS(main->curves.first, ADT_RECALC_ANIM);

	/* armatures */
	EVAL_ANIM_IDS(main->armatures.first, ADT_RECALC_ANIM);

	/* lattices */
	EVAL_ANIM_IDS(main->lattices.first, ADT_RECALC_ANIM);

	/* meshes */
	EVAL_ANIM_IDS(main->meshes.first, ADT_RECALC_ANIM);

	/* particles */
	EVAL_ANIM_IDS(main->particles.first, ADT_RECALC_ANIM);

	/* speakers */
	EVAL_ANIM_IDS(main->speakers.first, ADT_RECALC_ANIM);

	/* movie clips */
	EVAL_ANIM_IDS(main->movieclips.first, ADT_RECALC_ANIM);

	/* linestyles */
	EVAL_ANIM_IDS(main->linestyles.first, ADT_RECALC_ANIM);

	/* grease pencil */
	EVAL_ANIM_IDS(main->gpencils.first, ADT_RECALC_ANIM);

	/* palettes */
	EVAL_ANIM_IDS(main->palettes.first, ADT_RECALC_ANIM);

	/* cache files */
	EVAL_ANIM_IDS(main->cachefiles.first, ADT_RECALC_ANIM);

	/* objects */
	/* ADT_RECALC_ANIM doesn't need to be supplied here, since object AnimData gets
	 * this tagged by Depsgraph on framechange. This optimization means that objects
	 * linked from other (not-visible) scenes will not need their data calculated.
	 */
	EVAL_ANIM_IDS(main->objects.first, 0);

	/* masks */
	EVAL_ANIM_IDS(main->masks.first, ADT_RECALC_ANIM);

	/* worlds */
	EVAL_ANIM_NODETREE_IDS(main->worlds.first, World, ADT_RECALC_ANIM);

	/* scenes */
	EVAL_ANIM_NODETREE_IDS(main->scenes.first, Scene, ADT_RECALC_ANIM);
}

/* ***************************************** */

/* ************** */
/* Evaluation API */

void BKE_animsys_eval_animdata(Depsgraph *depsgraph, ID *id)
{
	float ctime = DEG_get_ctime(depsgraph);
	AnimData *adt = BKE_animdata_from_id(id);
	Scene *scene = NULL; /* XXX: this is only needed for flushing RNA updates,
	                      * which should get handled as part of the dependency graph instead...
	                      */
	DEG_debug_print_eval_time(depsgraph, __func__, id->name, id, ctime);
	BKE_animsys_evaluate_animdata(depsgraph, scene, id, adt, ctime, ADT_RECALC_ANIM);
}

void BKE_animsys_update_driver_array(ID *id)
{
	AnimData *adt = BKE_animdata_from_id(id);

	/* Runtime driver map to avoid O(n^2) lookups in BKE_animsys_eval_driver.
	 * Ideally the depsgraph could pass a pointer to the COW driver directly,
	 * but this is difficult in the current design. */
	if (adt && adt->drivers.first) {
		BLI_assert(!adt->driver_array);

		int num_drivers = BLI_listbase_count(&adt->drivers);
		adt->driver_array = MEM_mallocN(sizeof(FCurve *) * num_drivers, "adt->driver_array");

		int driver_index = 0;
		for (FCurve *fcu = adt->drivers.first; fcu; fcu = fcu->next) {
			adt->driver_array[driver_index++] = fcu;
		}
	}
}

void BKE_animsys_eval_driver(Depsgraph *depsgraph,
                             ID *id,
                             int driver_index,
                             ChannelDriver *driver_orig)
{
	/* TODO(sergey): De-duplicate with BKE animsys. */
	PointerRNA id_ptr;
	bool ok = false;

	/* Lookup driver, accelerated with driver array map. */
	const AnimData *adt = BKE_animdata_from_id(id);
	FCurve *fcu;

	if (adt->driver_array) {
		fcu = adt->driver_array[driver_index];
	}
	else {
		fcu = BLI_findlink(&adt->drivers, driver_index);
	}

	DEG_debug_print_eval_subdata_index(
	        depsgraph, __func__, id->name, id, "fcu", fcu->rna_path, fcu, fcu->array_index);

	RNA_id_pointer_create(id, &id_ptr);

	/* check if this driver's curve should be skipped */
	if ((fcu->flag & (FCURVE_MUTED | FCURVE_DISABLED)) == 0) {
		/* check if driver itself is tagged for recalculation */
		/* XXX driver recalc flag is not set yet by depsgraph! */
		if ((driver_orig) && !(driver_orig->flag & DRIVER_FLAG_INVALID)) {
			/* evaluate this using values set already in other places
			 * NOTE: for 'layering' option later on, we should check if we should remove old value before adding
			 *       new to only be done when drivers only changed */
			//printf("\told val = %f\n", fcu->curval);

			PathResolvedRNA anim_rna;
			if (animsys_store_rna_setting(&id_ptr, fcu->rna_path, fcu->array_index, &anim_rna)) {
				/* Evaluate driver, and write results to COW-domain destination */
				const float ctime = DEG_get_ctime(depsgraph);
				const float curval = evaluate_fcurve_driver(&anim_rna, fcu, driver_orig, ctime);
				ok = animsys_write_rna_setting(&anim_rna, curval);

				/* Flush results & status codes to original data for UI (T59984) */
				if (ok && DEG_is_active(depsgraph)) {
					animsys_write_orig_anim_rna(&id_ptr, fcu->rna_path, fcu->array_index, curval);

					/* curval is displayed in the UI, and flag contains error-status codes */
					driver_orig->curval = fcu->driver->curval;
					driver_orig->flag = fcu->driver->flag;

					DriverVar *dvar_orig = driver_orig->variables.first;
					DriverVar *dvar = fcu->driver->variables.first;
					for (;
					     dvar_orig && dvar;
					     dvar_orig = dvar_orig->next, dvar = dvar->next)
					{
						DriverTarget *dtar_orig = &dvar_orig->targets[0];
						DriverTarget *dtar = &dvar->targets[0];
						for (int i = 0; i < MAX_DRIVER_TARGETS; i++, dtar_orig++, dtar++) {
							dtar_orig->flag = dtar->flag;
						}

						dvar_orig->curval = dvar->curval;
						dvar_orig->flag = dvar->flag;
					}
				}
			}

			/* set error-flag if evaluation failed */
			if (ok == 0) {
				CLOG_ERROR(&LOG, "invalid driver - %s[%d]", fcu->rna_path, fcu->array_index);
				driver_orig->flag |= DRIVER_FLAG_INVALID;
			}
		}
	}
}