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

/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/blenkernel/intern/anim.c
 *  \ingroup bke
 */

#include "MEM_guardedalloc.h"

#include <stdlib.h>

#include "BLI_listbase.h"
#include "BLI_math.h"
#include "BLI_dlrbTree.h"

#include "BLT_translation.h"

#include "DNA_anim_types.h"
#include "DNA_armature_types.h"
#include "DNA_key_types.h"
#include "DNA_scene_types.h"

#include "BKE_anim.h"
#include "BKE_animsys.h"
#include "BKE_action.h"
#include "BKE_context.h"
#include "BKE_curve.h"
#include "BKE_global.h"
#include "BKE_key.h"
#include "BKE_main.h"
#include "BKE_object.h"
#include "BKE_particle.h"
#include "BKE_scene.h"
#include "BKE_report.h"

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

#include "GPU_batch.h"

// XXX bad level call...
extern short compare_ak_cfraPtr(void *node, void *data);
extern void agroup_to_keylist(struct AnimData *adt, struct bActionGroup *agrp, struct DLRBT_Tree *keys);
extern void action_to_keylist(struct AnimData *adt, struct bAction *act, struct DLRBT_Tree *keys);

/* --------------------- */
/* forward declarations */

/* ******************************************************************** */
/* Animation Visualization */

/* Initialize the default settings for animation visualization */
void animviz_settings_init(bAnimVizSettings *avs)
{
	/* sanity check */
	if (avs == NULL)
		return;

	/* ghosting settings */
	avs->ghost_bc = avs->ghost_ac = 10;

	avs->ghost_sf = 1; /* xxx - take from scene instead? */
	avs->ghost_ef = 250; /* xxx - take from scene instead? */

	avs->ghost_step = 1;


	/* path settings */
	avs->path_bc = avs->path_ac = 10;

	avs->path_sf = 1; /* xxx - take from scene instead? */
	avs->path_ef = 250; /* xxx - take from scene instead? */

	avs->path_viewflag = (MOTIONPATH_VIEW_KFRAS | MOTIONPATH_VIEW_KFNOS);

	avs->path_step = 1;

	avs->path_bakeflag |= MOTIONPATH_BAKE_HEADS;
}

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

/* Free the given motion path's cache */
void animviz_free_motionpath_cache(bMotionPath *mpath)
{
	/* sanity check */
	if (mpath == NULL)
		return;

	/* free the path if necessary */
	if (mpath->points)
		MEM_freeN(mpath->points);

	GPU_VERTBUF_DISCARD_SAFE(mpath->points_vbo);
	GPU_BATCH_DISCARD_SAFE(mpath->batch_line);
	GPU_BATCH_DISCARD_SAFE(mpath->batch_points);

	/* reset the relevant parameters */
	mpath->points = NULL;
	mpath->length = 0;
}

/* Free the given motion path instance and its data
 * NOTE: this frees the motion path given!
 */
void animviz_free_motionpath(bMotionPath *mpath)
{
	/* sanity check */
	if (mpath == NULL)
		return;

	/* free the cache first */
	animviz_free_motionpath_cache(mpath);

	/* now the instance itself */
	MEM_freeN(mpath);
}

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

/* Make a copy of motionpath data, so that viewing with copy on write works */
bMotionPath *animviz_copy_motionpath(const bMotionPath *mpath_src)
{
	bMotionPath *mpath_dst;

	if (mpath_src == NULL)
		return NULL;

	mpath_dst = MEM_dupallocN(mpath_src);
	mpath_dst->points = MEM_dupallocN(mpath_src->points);

	/* should get recreated on draw... */
	mpath_dst->points_vbo = NULL;
	mpath_dst->batch_line = NULL;
	mpath_dst->batch_points = NULL;

	return mpath_dst;
}

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

/**
 * Setup motion paths for the given data.
 * \note Only used when explicitly calculating paths on bones which may/may not be consider already
 *
 * \param scene Current scene (for frame ranges, etc.)
 * \param ob Object to add paths for (must be provided)
 * \param pchan Posechannel to add paths for (optional; if not provided, object-paths are assumed)
 */
bMotionPath *animviz_verify_motionpaths(ReportList *reports, Scene *scene, Object *ob, bPoseChannel *pchan)
{
	bAnimVizSettings *avs;
	bMotionPath *mpath, **dst;

	/* sanity checks */
	if (ELEM(NULL, scene, ob))
		return NULL;

	/* get destination data */
	if (pchan) {
		/* paths for posechannel - assume that posechannel belongs to the object */
		avs = &ob->pose->avs;
		dst = &pchan->mpath;
	}
	else {
		/* paths for object */
		avs = &ob->avs;
		dst = &ob->mpath;
	}

	/* avoid 0 size allocs */
	if (avs->path_sf >= avs->path_ef) {
		BKE_reportf(reports, RPT_ERROR,
		            "Motion path frame extents invalid for %s (%d to %d)%s",
		            (pchan) ? pchan->name : ob->id.name,
		            avs->path_sf, avs->path_ef,
		            (avs->path_sf == avs->path_ef) ? TIP_(", cannot have single-frame paths") : "");
		return NULL;
	}

	/* if there is already a motionpath, just return that,
	 * provided it's settings are ok (saves extra free+alloc)
	 */
	if (*dst != NULL) {
		int expected_length = avs->path_ef - avs->path_sf;

		mpath = *dst;

		/* path is "valid" if length is valid, but must also be of the same length as is being requested */
		if ((mpath->start_frame != mpath->end_frame) && (mpath->length > 0)) {
			/* outer check ensures that we have some curve data for this path */
			if (mpath->length == expected_length) {
				/* return/use this as it is already valid length */
				return mpath;
			}
			else {
				/* clear the existing path (as the range has changed), and reallocate below */
				animviz_free_motionpath_cache(mpath);
			}
		}
	}
	else {
		/* create a new motionpath, and assign it */
		mpath = MEM_callocN(sizeof(bMotionPath), "bMotionPath");
		*dst = mpath;
	}

	/* set settings from the viz settings */
	mpath->start_frame = avs->path_sf;
	mpath->end_frame = avs->path_ef;

	mpath->length = mpath->end_frame - mpath->start_frame;

	if (avs->path_bakeflag & MOTIONPATH_BAKE_HEADS)
		mpath->flag |= MOTIONPATH_FLAG_BHEAD;
	else
		mpath->flag &= ~MOTIONPATH_FLAG_BHEAD;

	/* set default custom values */
	mpath->color[0] = 1.0;    /* Red */
	mpath->color[1] = 0.0;
	mpath->color[2] = 0.0;

	mpath->line_thickness = 2;
	mpath->flag |= MOTIONPATH_FLAG_LINES;  /* draw lines by default */

	/* allocate a cache */
	mpath->points = MEM_callocN(sizeof(bMotionPathVert) * mpath->length, "bMotionPathVerts");

	/* tag viz settings as currently having some path(s) which use it */
	avs->path_bakeflag |= MOTIONPATH_BAKE_HAS_PATHS;

	/* return it */
	return mpath;
}

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

/* Motion path needing to be baked (mpt) */
typedef struct MPathTarget {
	struct MPathTarget *next, *prev;

	bMotionPath *mpath;         /* motion path in question */

	DLRBT_Tree keys;         /* temp, to know where the keyframes are */

	/* Original (Source Objects) */
	Object *ob;                 /* source object */
	bPoseChannel *pchan;        /* source posechannel (if applicable) */

	/* "Evaluated" Copies (these come from the background COW copie
	 * that provide all the coordinates we want to save off)
	 */
	Object *ob_eval;             /* evaluated object */
} MPathTarget;

/* ........ */

/* get list of motion paths to be baked for the given object
 *  - assumes the given list is ready to be used
 */
/* TODO: it would be nice in future to be able to update objects dependent on these bones too? */
void animviz_get_object_motionpaths(Object *ob, ListBase *targets)
{
	MPathTarget *mpt;

	/* object itself first */
	if ((ob->avs.recalc & ANIMVIZ_RECALC_PATHS) && (ob->mpath)) {
		/* new target for object */
		mpt = MEM_callocN(sizeof(MPathTarget), "MPathTarget Ob");
		BLI_addtail(targets, mpt);

		mpt->mpath = ob->mpath;
		mpt->ob = ob;
	}

	/* bones */
	if ((ob->pose) && (ob->pose->avs.recalc & ANIMVIZ_RECALC_PATHS)) {
		bArmature *arm = ob->data;
		bPoseChannel *pchan;

		for (pchan = ob->pose->chanbase.first; pchan; pchan = pchan->next) {
			if ((pchan->bone) && (arm->layer & pchan->bone->layer) && (pchan->mpath)) {
				/* new target for bone */
				mpt = MEM_callocN(sizeof(MPathTarget), "MPathTarget PoseBone");
				BLI_addtail(targets, mpt);

				mpt->mpath = pchan->mpath;
				mpt->ob = ob;
				mpt->pchan = pchan;
			}
		}
	}
}

/* ........ */

/* update scene for current frame */
static void motionpaths_calc_update_scene(Main *bmain,
                                          struct Depsgraph *depsgraph)
{
	/* Do all updates
	 *  - if this is too slow, resort to using a more efficient way
	 *    that doesn't force complete update, but for now, this is the
	 *    most accurate way!
	 *
	 * TODO(segey): Bring back partial updates, which became impossible
	 * with the new depsgraph due to unsorted nature of bases.
	 *
	 * TODO(sergey): Use evaluation context dedicated to motion paths.
	 */
	BKE_scene_graph_update_for_newframe(depsgraph, bmain);
}

/* ........ */

/* perform baking for the targets on the current frame */
static void motionpaths_calc_bake_targets(ListBase *targets, int cframe)
{
	MPathTarget *mpt;

	/* for each target, check if it can be baked on the current frame */
	for (mpt = targets->first; mpt; mpt = mpt->next) {
		bMotionPath *mpath = mpt->mpath;

		/* current frame must be within the range the cache works for
		 *	- is inclusive of the first frame, but not the last otherwise we get buffer overruns
		 */
		if ((cframe < mpath->start_frame) || (cframe >= mpath->end_frame)) {
			continue;
		}

		/* get the relevant cache vert to write to */
		bMotionPathVert *mpv = mpath->points + (cframe - mpath->start_frame);

		Object *ob_eval = mpt->ob_eval;

		/* Lookup evaluated pose channel, here because the depsgraph
		 * evaluation can change them so they are not cached in mpt. */
		bPoseChannel *pchan_eval = NULL;
		if (mpt->pchan) {
			pchan_eval = BKE_pose_channel_find_name(ob_eval->pose, mpt->pchan->name);
		}

		/* pose-channel or object path baking? */
		if (pchan_eval) {
			/* heads or tails */
			if (mpath->flag & MOTIONPATH_FLAG_BHEAD) {
				copy_v3_v3(mpv->co, pchan_eval->pose_head);
			}
			else {
				copy_v3_v3(mpv->co, pchan_eval->pose_tail);
			}

			/* result must be in worldspace */
			mul_m4_v3(ob_eval->obmat, mpv->co);
		}
		else {
			/* worldspace object location */
			copy_v3_v3(mpv->co, ob_eval->obmat[3]);
		}

		float mframe = (float)(cframe);

		/* Tag if it's a keyframe */
		if (BLI_dlrbTree_search_exact(&mpt->keys, compare_ak_cfraPtr, &mframe)) {
			mpv->flag |= MOTIONPATH_VERT_KEY;
		}

		/* Incremental update on evaluated object if possible, for fast updating
		 * while dragging in transform. */
		bMotionPath *mpath_eval = NULL;
		if (mpt->pchan) {
			mpath_eval = (pchan_eval) ? pchan_eval->mpath : NULL;
		}
		else {
			mpath_eval = ob_eval->mpath;
		}

		if (mpath_eval && mpath_eval->length == mpath->length) {
			bMotionPathVert *mpv_eval = mpath_eval->points + (cframe - mpath_eval->start_frame);
			*mpv_eval = *mpv;

			GPU_VERTBUF_DISCARD_SAFE(mpath_eval->points_vbo);
			GPU_BATCH_DISCARD_SAFE(mpath_eval->batch_line);
			GPU_BATCH_DISCARD_SAFE(mpath_eval->batch_points);
		}
	}
}

/* Perform baking of the given object's and/or its bones' transforms to motion paths
 *	- scene: current scene
 *	- ob: object whose flagged motionpaths should get calculated
 *	- recalc: whether we need to
 */
/* TODO: include reports pointer? */
void animviz_calc_motionpaths(Depsgraph *depsgraph,
                              Main *bmain,
                              Scene *scene,
                              ListBase *targets,
                              bool restore,
                              bool current_frame_only)
{
	/* sanity check */
	if (ELEM(NULL, targets, targets->first))
		return;

	/* Compute frame range to bake within.
	 * TODO: this method could be improved...
	 * 1) max range for standard baking
	 * 2) minimum range for recalc baking (i.e. between keyframes, but how?) */
	int sfra = INT_MAX;
	int efra = INT_MIN;

	for (MPathTarget *mpt = targets->first; mpt; mpt = mpt->next) {
		/* try to increase area to do (only as much as needed) */
		sfra = MIN2(sfra, mpt->mpath->start_frame);
		efra = MAX2(efra, mpt->mpath->end_frame);
	}

	if (efra <= sfra) {
		return;
	}

	/* Limit frame range if we are updating just the current frame. */
	/* set frame values */
	int cfra = CFRA;
	if (current_frame_only) {
		if (cfra < sfra || cfra > efra) {
			return;
		}
		sfra = efra = cfra;
	}

	/* get copies of objects/bones to get the calculated results from
	 * (for copy-on-write evaluation), so that we actually get some results
	 */
	// TODO: Create a copy of background depsgraph that only contain these entities, and only evaluates them..
	for (MPathTarget *mpt = targets->first; mpt; mpt = mpt->next) {
		mpt->ob_eval = DEG_get_evaluated_object(depsgraph, mpt->ob);

		AnimData *adt = BKE_animdata_from_id(&mpt->ob_eval->id);

		/* build list of all keyframes in active action for object or pchan */
		BLI_dlrbTree_init(&mpt->keys);

		if (adt) {
			bAnimVizSettings *avs;

			/* get pointer to animviz settings for each target */
			if (mpt->pchan)
				avs = &mpt->ob->pose->avs;
			else
				avs = &mpt->ob->avs;

			/* it is assumed that keyframes for bones are all grouped in a single group
			 * unless an option is set to always use the whole action
			 */
			if ((mpt->pchan) && (avs->path_viewflag & MOTIONPATH_VIEW_KFACT) == 0) {
				bActionGroup *agrp = BKE_action_group_find_name(adt->action, mpt->pchan->name);

				if (agrp) {
					agroup_to_keylist(adt, agrp, &mpt->keys);
				}
			}
			else {
				action_to_keylist(adt, adt->action, &mpt->keys);
			}
		}
	}

	/* calculate path over requested range */
	printf("Calculating MotionPaths between frames %d - %d (%d frames)\n", sfra, efra, efra - sfra + 1);
	for (CFRA = sfra; CFRA <= efra; CFRA++) {
		if (current_frame_only) {
			/* For current frame, only update tagged. */
			BKE_scene_graph_update_tagged(depsgraph, bmain);
		}
		else {
			/* Update relevant data for new frame. */
			motionpaths_calc_update_scene(bmain, depsgraph);
		}

		/* perform baking for targets */
		motionpaths_calc_bake_targets(targets, CFRA);
	}

	/* reset original environment */
	/* NOTE: We don't always need to reevaluate the main scene, as the depsgraph
	 * may be a temporary one that works on a subset of the data. We always have
	 * to resoture the current frame though. */
	CFRA = cfra;
	if (!current_frame_only && restore) {
		motionpaths_calc_update_scene(bmain, depsgraph);
	}

	/* clear recalc flags from targets */
	for (MPathTarget *mpt = targets->first; mpt; mpt = mpt->next) {
		bAnimVizSettings *avs;
		bMotionPath *mpath = mpt->mpath;

		/* get pointer to animviz settings for each target */
		if (mpt->pchan)
			avs = &mpt->ob->pose->avs;
		else
			avs = &mpt->ob->avs;

		/* clear the flag requesting recalculation of targets */
		avs->recalc &= ~ANIMVIZ_RECALC_PATHS;

		/* Clean temp data */
		BLI_dlrbTree_free(&mpt->keys);

		/* Free previous batches to force update. */
		GPU_VERTBUF_DISCARD_SAFE(mpath->points_vbo);
		GPU_BATCH_DISCARD_SAFE(mpath->batch_line);
		GPU_BATCH_DISCARD_SAFE(mpath->batch_points);
	}
}

/* ******************************************************************** */
/* Curve Paths - for curve deforms and/or curve following */

/* free curve path data
 * NOTE: frees the path itself!
 * NOTE: this is increasingly inaccurate with non-uniform BevPoint subdivisions [#24633]
 */
void free_path(Path *path)
{
	if (path->data) MEM_freeN(path->data);
	MEM_freeN(path);
}

/* calculate a curve-deform path for a curve
 *  - only called from displist.c -> do_makeDispListCurveTypes
 */
void calc_curvepath(Object *ob, ListBase *nurbs)
{
	BevList *bl;
	BevPoint *bevp, *bevpn, *bevpfirst, *bevplast;
	PathPoint *pp;
	Nurb *nu;
	Path *path;
	float *fp, *dist, *maxdist, xyz[3];
	float fac, d = 0, fac1, fac2;
	int a, tot, cycl = 0;

	/* in a path vertices are with equal differences: path->len = number of verts */
	/* NOW WITH BEVELCURVE!!! */

	if (ob == NULL || ob->type != OB_CURVE) {
		return;
	}

	if (ob->runtime.curve_cache->path) free_path(ob->runtime.curve_cache->path);
	ob->runtime.curve_cache->path = NULL;

	/* weak! can only use first curve */
	bl = ob->runtime.curve_cache->bev.first;
	if (bl == NULL || !bl->nr) {
		return;
	}

	nu = nurbs->first;

	ob->runtime.curve_cache->path = path = MEM_callocN(sizeof(Path), "calc_curvepath");

	/* if POLY: last vertice != first vertice */
	cycl = (bl->poly != -1);

	tot = cycl ? bl->nr : bl->nr - 1;

	path->len = tot + 1;
	/* exception: vector handle paths and polygon paths should be subdivided at least a factor resolu */
	if (path->len < nu->resolu * SEGMENTSU(nu)) {
		path->len = nu->resolu * SEGMENTSU(nu);
	}

	dist = (float *)MEM_mallocN(sizeof(float) * (tot + 1), "calcpathdist");

	/* all lengths in *dist */
	bevp = bevpfirst = bl->bevpoints;
	fp = dist;
	*fp = 0.0f;
	for (a = 0; a < tot; a++) {
		fp++;
		if (cycl && a == tot - 1)
			sub_v3_v3v3(xyz, bevpfirst->vec, bevp->vec);
		else
			sub_v3_v3v3(xyz, (bevp + 1)->vec, bevp->vec);

		*fp = *(fp - 1) + len_v3(xyz);
		bevp++;
	}

	path->totdist = *fp;

	/* the path verts  in path->data */
	/* now also with TILT value */
	pp = path->data = (PathPoint *)MEM_callocN(sizeof(PathPoint) * path->len, "pathdata");

	bevp = bevpfirst;
	bevpn = bevp + 1;
	bevplast = bevpfirst + (bl->nr - 1);
	if (UNLIKELY(bevpn > bevplast)) {
		bevpn = cycl ? bevpfirst : bevplast;
	}
	fp = dist + 1;
	maxdist = dist + tot;
	fac = 1.0f / ((float)path->len - 1.0f);
	fac = fac * path->totdist;

	for (a = 0; a < path->len; a++) {

		d = ((float)a) * fac;

		/* we're looking for location (distance) 'd' in the array */
		if (LIKELY(tot > 0)) {
			while ((fp < maxdist) && (d >= *fp)) {
				fp++;
				if (bevp < bevplast) bevp++;
				bevpn = bevp + 1;
				if (UNLIKELY(bevpn > bevplast)) {
					bevpn = cycl ? bevpfirst : bevplast;
				}
			}

			fac1 = (*(fp) - d) / (*(fp) - *(fp - 1));
			fac2 = 1.0f - fac1;
		}
		else {
			fac1 = 1.0f;
			fac2 = 0.0f;
		}

		interp_v3_v3v3(pp->vec, bevp->vec, bevpn->vec, fac2);
		pp->vec[3] = fac1 * bevp->alfa   + fac2 * bevpn->alfa;
		pp->radius = fac1 * bevp->radius + fac2 * bevpn->radius;
		pp->weight = fac1 * bevp->weight + fac2 * bevpn->weight;
		interp_qt_qtqt(pp->quat, bevp->quat, bevpn->quat, fac2);
		normalize_qt(pp->quat);

		pp++;
	}

	MEM_freeN(dist);
}

static int interval_test(const int min, const int max, int p1, const int cycl)
{
	if (cycl) {
		p1 = mod_i(p1 - min, (max - min + 1)) + min;
	}
	else {
		if      (p1 < min) p1 = min;
		else if (p1 > max) p1 = max;
	}
	return p1;
}


/* calculate the deformation implied by the curve path at a given parametric position,
 * and returns whether this operation succeeded.
 *
 * note: ctime is normalized range <0-1>
 *
 * returns OK: 1/0
 */
int where_on_path(Object *ob, float ctime, float vec[4], float dir[3], float quat[4], float *radius, float *weight)
{
	Curve *cu;
	Nurb *nu;
	BevList *bl;
	Path *path;
	PathPoint *pp, *p0, *p1, *p2, *p3;
	float fac;
	float data[4];
	int cycl = 0, s0, s1, s2, s3;
	ListBase *nurbs;

	if (ob == NULL || ob->type != OB_CURVE) return 0;
	cu = ob->data;
	if (ob->runtime.curve_cache == NULL || ob->runtime.curve_cache->path == NULL || ob->runtime.curve_cache->path->data == NULL) {
		printf("no path!\n");
		return 0;
	}
	path = ob->runtime.curve_cache->path;
	pp = path->data;

	/* test for cyclic */
	bl = ob->runtime.curve_cache->bev.first;
	if (!bl) return 0;
	if (!bl->nr) return 0;
	if (bl->poly > -1) cycl = 1;

	/* values below zero for non-cyclic curves give strange results */
	BLI_assert(cycl || ctime >= 0.0f);

	ctime *= (path->len - 1);

	s1 = (int)floor(ctime);
	fac = (float)(s1 + 1) - ctime;

	/* path->len is corrected for cyclic */
	s0 = interval_test(0, path->len - 1 - cycl, s1 - 1, cycl);
	s1 = interval_test(0, path->len - 1 - cycl, s1, cycl);
	s2 = interval_test(0, path->len - 1 - cycl, s1 + 1, cycl);
	s3 = interval_test(0, path->len - 1 - cycl, s1 + 2, cycl);

	p0 = pp + s0;
	p1 = pp + s1;
	p2 = pp + s2;
	p3 = pp + s3;

	/* NOTE: commented out for follow constraint
	 *
	 *       If it's ever be uncommented watch out for curve_deform_verts()
	 *       which used to temporary set CU_FOLLOW flag for the curve and no
	 *       longer does it (because of threading issues of such a thing.
	 */
	//if (cu->flag & CU_FOLLOW) {

	key_curve_tangent_weights(1.0f - fac, data, KEY_BSPLINE);

	interp_v3_v3v3v3v3(dir, p0->vec, p1->vec, p2->vec, p3->vec, data);

	/* make compatible with vectoquat */
	negate_v3(dir);
	//}

	nurbs = BKE_curve_editNurbs_get(cu);
	if (!nurbs)
		nurbs = &cu->nurb;
	nu = nurbs->first;

	/* make sure that first and last frame are included in the vectors here  */
	if (nu->type == CU_POLY) key_curve_position_weights(1.0f - fac, data, KEY_LINEAR);
	else if (nu->type == CU_BEZIER) key_curve_position_weights(1.0f - fac, data, KEY_LINEAR);
	else if (s0 == s1 || p2 == p3) key_curve_position_weights(1.0f - fac, data, KEY_CARDINAL);
	else key_curve_position_weights(1.0f - fac, data, KEY_BSPLINE);

	vec[0] = data[0] * p0->vec[0] + data[1] * p1->vec[0] + data[2] * p2->vec[0] + data[3] * p3->vec[0]; /* X */
	vec[1] = data[0] * p0->vec[1] + data[1] * p1->vec[1] + data[2] * p2->vec[1] + data[3] * p3->vec[1]; /* Y */
	vec[2] = data[0] * p0->vec[2] + data[1] * p1->vec[2] + data[2] * p2->vec[2] + data[3] * p3->vec[2]; /* Z */
	vec[3] = data[0] * p0->vec[3] + data[1] * p1->vec[3] + data[2] * p2->vec[3] + data[3] * p3->vec[3]; /* Tilt, should not be needed since we have quat still used */

	if (quat) {
		float totfac, q1[4], q2[4];

		totfac = data[0] + data[3];
		if (totfac > FLT_EPSILON) interp_qt_qtqt(q1, p0->quat, p3->quat, data[3] / totfac);
		else copy_qt_qt(q1, p1->quat);

		totfac = data[1] + data[2];
		if (totfac > FLT_EPSILON) interp_qt_qtqt(q2, p1->quat, p2->quat, data[2] / totfac);
		else copy_qt_qt(q2, p3->quat);

		totfac = data[0] + data[1] + data[2] + data[3];
		if (totfac > FLT_EPSILON) interp_qt_qtqt(quat, q1, q2, (data[1] + data[2]) / totfac);
		else copy_qt_qt(quat, q2);
	}

	if (radius)
		*radius = data[0] * p0->radius + data[1] * p1->radius + data[2] * p2->radius + data[3] * p3->radius;

	if (weight)
		*weight = data[0] * p0->weight + data[1] * p1->weight + data[2] * p2->weight + data[3] * p3->weight;

	return 1;
}