blender-archive/source/blender/blenkernel/intern/gpencil.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) 2008, Blender Foundation
 * This is a new part of Blender
 */

/** \file
 * \ingroup bke
 */


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

#include "CLG_log.h"

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"
#include "BLI_utildefines.h"
#include "BLI_math_vector.h"
#include "BLI_string_utils.h"

#include "BLT_translation.h"

#include "DNA_anim_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_material_types.h"
#include "DNA_gpencil_types.h"
#include "DNA_userdef_types.h"
#include "DNA_scene_types.h"
#include "DNA_object_types.h"

#include "BKE_action.h"
#include "BKE_animsys.h"
#include "BKE_deform.h"
#include "BKE_gpencil.h"
#include "BKE_colortools.h"
#include "BKE_icons.h"
#include "BKE_library.h"
#include "BKE_main.h"
#include "BKE_object.h"
#include "BKE_material.h"

#include "DEG_depsgraph.h"

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

/* ************************************************** */
/* Draw Engine */

void(*BKE_gpencil_batch_cache_dirty_tag_cb)(bGPdata *gpd) = NULL;
void(*BKE_gpencil_batch_cache_free_cb)(bGPdata *gpd) = NULL;

void BKE_gpencil_batch_cache_dirty_tag(bGPdata *gpd)
{
	if (gpd) {
		DEG_id_tag_update(&gpd->id, ID_RECALC_GEOMETRY);
		BKE_gpencil_batch_cache_dirty_tag_cb(gpd);
	}
}

void BKE_gpencil_batch_cache_free(bGPdata *gpd)
{
	if (gpd) {
		BKE_gpencil_batch_cache_free_cb(gpd);
	}
}

/* ************************************************** */
/* Memory Management */

/* clean vertex groups weights */
void BKE_gpencil_free_point_weights(MDeformVert *dvert)
{
	if (dvert == NULL) {
		return;
	}
	MEM_SAFE_FREE(dvert->dw);
}

void BKE_gpencil_free_stroke_weights(bGPDstroke *gps)
{
	if (gps == NULL) {
		return;
	}

	if (gps->dvert == NULL) {
		return;
	}

	for (int i = 0; i < gps->totpoints; i++) {
		MDeformVert *dvert = &gps->dvert[i];
		BKE_gpencil_free_point_weights(dvert);
	}
}

/* free stroke, doesn't unlink from any listbase */
void BKE_gpencil_free_stroke(bGPDstroke *gps)
{
	if (gps == NULL) {
		return;
	}
	/* free stroke memory arrays, then stroke itself */
	if (gps->points) {
		MEM_freeN(gps->points);
	}
	if (gps->dvert) {
		BKE_gpencil_free_stroke_weights(gps);
		MEM_freeN(gps->dvert);
	}
	if (gps->triangles)
		MEM_freeN(gps->triangles);

	MEM_freeN(gps);
}

/* Free strokes belonging to a gp-frame */
bool BKE_gpencil_free_strokes(bGPDframe *gpf)
{
	bGPDstroke *gps_next;
	bool changed = (BLI_listbase_is_empty(&gpf->strokes) == false);

	/* free strokes */
	for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps_next) {
		gps_next = gps->next;
		BKE_gpencil_free_stroke(gps);
	}
	BLI_listbase_clear(&gpf->strokes);

	return changed;
}

/* Free strokes and colors belonging to a gp-frame */
bool BKE_gpencil_free_frame_runtime_data(bGPDframe *derived_gpf)
{
	bGPDstroke *gps_next;
	if (!derived_gpf) {
		return false;
	}

	/* free strokes */
	for (bGPDstroke *gps = derived_gpf->strokes.first; gps; gps = gps_next) {
		gps_next = gps->next;
		BKE_gpencil_free_stroke(gps);
	}
	BLI_listbase_clear(&derived_gpf->strokes);

	return true;
}

/* Free all of a gp-layer's frames */
void BKE_gpencil_free_frames(bGPDlayer *gpl)
{
	bGPDframe *gpf_next;

	/* error checking */
	if (gpl == NULL) return;

	/* free frames */
	for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf_next) {
		gpf_next = gpf->next;

		/* free strokes and their associated memory */
		BKE_gpencil_free_strokes(gpf);
		BLI_freelinkN(&gpl->frames, gpf);
	}
	gpl->actframe = NULL;
}



/* Free all of the gp-layers for a viewport (list should be &gpd->layers or so) */
void BKE_gpencil_free_layers(ListBase *list)
{
	bGPDlayer *gpl_next;

	/* error checking */
	if (list == NULL) return;

	/* delete layers */
	for (bGPDlayer *gpl = list->first; gpl; gpl = gpl_next) {
		gpl_next = gpl->next;

		/* free layers and their data */
		BKE_gpencil_free_frames(gpl);
		BLI_freelinkN(list, gpl);
	}
}

/** Free (or release) any data used by this grease pencil (does not free the gpencil itself). */
void BKE_gpencil_free(bGPdata *gpd, bool free_all)
{
	/* clear animation data */
	BKE_animdata_free(&gpd->id, false);

	/* free layers */
	BKE_gpencil_free_layers(&gpd->layers);

	/* materials */
	MEM_SAFE_FREE(gpd->mat);

	/* free all data */
	if (free_all) {
		/* clear cache */
		BKE_gpencil_batch_cache_free(gpd);
	}
}

/* ************************************************** */
/* Container Creation */

/* add a new gp-frame to the given layer */
bGPDframe *BKE_gpencil_frame_addnew(bGPDlayer *gpl, int cframe)
{
	bGPDframe *gpf = NULL, *gf = NULL;
	short state = 0;

	/* error checking */
	if (gpl == NULL)
		return NULL;

	/* allocate memory for this frame */
	gpf = MEM_callocN(sizeof(bGPDframe), "bGPDframe");
	gpf->framenum = cframe;

	/* find appropriate place to add frame */
	if (gpl->frames.first) {
		for (gf = gpl->frames.first; gf; gf = gf->next) {
			/* check if frame matches one that is supposed to be added */
			if (gf->framenum == cframe) {
				state = -1;
				break;
			}

			/* if current frame has already exceeded the frame to add, add before */
			if (gf->framenum > cframe) {
				BLI_insertlinkbefore(&gpl->frames, gf, gpf);
				state = 1;
				break;
			}
		}
	}

	/* check whether frame was added successfully */
	if (state == -1) {
		CLOG_ERROR(&LOG, "Frame (%d) existed already for this layer. Using existing frame", cframe);

		/* free the newly created one, and use the old one instead */
		MEM_freeN(gpf);

		/* return existing frame instead... */
		BLI_assert(gf != NULL);
		gpf = gf;
	}
	else if (state == 0) {
		/* add to end then! */
		BLI_addtail(&gpl->frames, gpf);
	}

	/* return frame */
	return gpf;
}

/* add a copy of the active gp-frame to the given layer */
bGPDframe *BKE_gpencil_frame_addcopy(bGPDlayer *gpl, int cframe)
{
	bGPDframe *new_frame;
	bool found = false;

	/* Error checking/handling */
	if (gpl == NULL) {
		/* no layer */
		return NULL;
	}
	else if (gpl->actframe == NULL) {
		/* no active frame, so just create a new one from scratch */
		return BKE_gpencil_frame_addnew(gpl, cframe);
	}

	/* Create a copy of the frame */
	new_frame = BKE_gpencil_frame_duplicate(gpl->actframe);

	/* Find frame to insert it before */
	for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
		if (gpf->framenum > cframe) {
			/* Add it here */
			BLI_insertlinkbefore(&gpl->frames, gpf, new_frame);

			found = true;
			break;
		}
		else if (gpf->framenum == cframe) {
			/* This only happens when we're editing with framelock on...
			 * - Delete the new frame and don't do anything else here...
			 */
			BKE_gpencil_free_strokes(new_frame);
			MEM_freeN(new_frame);
			new_frame = NULL;

			found = true;
			break;
		}
	}

	if (found == false) {
		/* Add new frame to the end */
		BLI_addtail(&gpl->frames, new_frame);
	}

	/* Ensure that frame is set up correctly, and return it */
	if (new_frame) {
		new_frame->framenum = cframe;
		gpl->actframe = new_frame;
	}

	return new_frame;
}

/* add a new gp-layer and make it the active layer */
bGPDlayer *BKE_gpencil_layer_addnew(bGPdata *gpd, const char *name, bool setactive)
{
	bGPDlayer *gpl = NULL;
	bGPDlayer *gpl_active = NULL;

	/* check that list is ok */
	if (gpd == NULL)
		return NULL;

	/* allocate memory for frame and add to end of list */
	gpl = MEM_callocN(sizeof(bGPDlayer), "bGPDlayer");

	gpl_active = BKE_gpencil_layer_getactive(gpd);

	/* add to datablock */
	if (gpl_active == NULL) {
		BLI_addtail(&gpd->layers, gpl);
	}
	else {
		/* if active layer, add after that layer */
		BLI_insertlinkafter(&gpd->layers, gpl_active, gpl);
	}

	/* annotation vs GP Object behavior is slightly different */
	if (gpd->flag & GP_DATA_ANNOTATIONS) {
		/* set default color of new strokes for this layer */
		copy_v4_v4(gpl->color, U.gpencil_new_layer_col);
		gpl->opacity = 1.0f;

		/* set default thickness of new strokes for this layer */
		gpl->thickness = 3;

		/* Onion colors */
		ARRAY_SET_ITEMS(gpl->gcolor_prev, 0.302f, 0.851f, 0.302f);
		ARRAY_SET_ITEMS(gpl->gcolor_next, 0.250f, 0.1f, 1.0f);
	}
	else {
		/* thickness parameter represents "thickness change", not absolute thickness */
		gpl->thickness = 0;
		gpl->opacity = 1.0f;
	}

	/* auto-name */
	BLI_strncpy(gpl->info, name, sizeof(gpl->info));
	BLI_uniquename(&gpd->layers, gpl,
	               (gpd->flag & GP_DATA_ANNOTATIONS) ? DATA_("Note") : DATA_("GP_Layer"),
	               '.',
	               offsetof(bGPDlayer, info),
	               sizeof(gpl->info));

	/* make this one the active one */
	if (setactive)
		BKE_gpencil_layer_setactive(gpd, gpl);

	/* return layer */
	return gpl;
}

/* add a new gp-datablock */
bGPdata *BKE_gpencil_data_addnew(Main *bmain, const char name[])
{
	bGPdata *gpd;

	/* allocate memory for a new block */
	gpd = BKE_libblock_alloc(bmain, ID_GD, name, 0);

	/* initial settings */
	gpd->flag = (GP_DATA_DISPINFO | GP_DATA_EXPAND);

	/* general flags */
	gpd->flag |= GP_DATA_VIEWALIGN;
	gpd->flag |= GP_DATA_STROKE_FORCE_RECALC;
	/* always enable object onion skin swith */
	gpd->flag |= GP_DATA_SHOW_ONIONSKINS;
	/* GP object specific settings */
	ARRAY_SET_ITEMS(gpd->line_color, 0.6f, 0.6f, 0.6f, 0.5f);

	gpd->xray_mode = GP_XRAY_3DSPACE;
	gpd->pixfactor = GP_DEFAULT_PIX_FACTOR;

	/* grid settings */
	ARRAY_SET_ITEMS(gpd->grid.color, 0.5f, 0.5f, 0.5f); // Color
	ARRAY_SET_ITEMS(gpd->grid.scale, 1.0f, 1.0f); // Scale
	gpd->grid.lines = GP_DEFAULT_GRID_LINES; // Number of lines

	/* onion-skinning settings (datablock level) */
	gpd->onion_flag |= (GP_ONION_GHOST_PREVCOL | GP_ONION_GHOST_NEXTCOL);
	gpd->onion_flag |= GP_ONION_FADE;
	gpd->onion_mode = GP_ONION_MODE_RELATIVE;
	gpd->onion_factor = 0.5f;
	ARRAY_SET_ITEMS(gpd->gcolor_prev, 0.145098f, 0.419608f, 0.137255f); /* green */
	ARRAY_SET_ITEMS(gpd->gcolor_next, 0.125490f, 0.082353f, 0.529412f); /* blue */
	gpd->gstep = 1;
	gpd->gstep_next = 1;

	return gpd;
}


/* ************************************************** */
/* Primitive Creation */
/* Utilities for easier bulk-creation of geometry */

/**
 * Populate stroke with point data from data buffers
 *
 * \param array: Flat array of point data values. Each entry has GP_PRIM_DATABUF_SIZE values
 * \param mat: 4x4 transform matrix to transform points into the right coordinate space
 */
void BKE_gpencil_stroke_add_points(bGPDstroke *gps, const float *array, const int totpoints, const float mat[4][4])
{
	for (int i = 0; i < totpoints; i++) {
		bGPDspoint *pt = &gps->points[i];
		const int x = GP_PRIM_DATABUF_SIZE * i;

		pt->x = array[x];
		pt->y = array[x + 1];
		pt->z = array[x + 2];
		mul_m4_v3(mat, &pt->x);

		pt->pressure = array[x + 3];
		pt->strength = array[x + 4];
	}
}

/* Create a new stroke, with pre-allocated data buffers */
bGPDstroke *BKE_gpencil_add_stroke(bGPDframe *gpf, int mat_idx, int totpoints, short thickness)
{
	/* allocate memory for a new stroke */
	bGPDstroke *gps = MEM_callocN(sizeof(bGPDstroke), "gp_stroke");

	gps->thickness = thickness;
	gps->inittime = 0;

	/* enable recalculation flag by default */
	gps->flag = GP_STROKE_RECALC_GEOMETRY | GP_STROKE_3DSPACE;

	gps->totpoints = totpoints;
	gps->points = MEM_callocN(sizeof(bGPDspoint) * gps->totpoints, "gp_stroke_points");

	/* initialize triangle memory to dummy data */
	gps->triangles = MEM_callocN(sizeof(bGPDtriangle), "GP Stroke triangulation");
	gps->flag |= GP_STROKE_RECALC_GEOMETRY;
	gps->tot_triangles = 0;

	gps->mat_nr = mat_idx;

	/* add to frame */
	BLI_addtail(&gpf->strokes, gps);

	return gps;
}


/* ************************************************** */
/* Data Duplication */

/* make a copy of a given gpencil weights */
void BKE_gpencil_stroke_weights_duplicate(bGPDstroke *gps_src, bGPDstroke *gps_dst)
{
	if (gps_src == NULL) {
		return;
	}
	BLI_assert(gps_src->totpoints == gps_dst->totpoints);

	BKE_defvert_array_copy(gps_dst->dvert, gps_src->dvert, gps_src->totpoints);
}

/* make a copy of a given gpencil stroke */
bGPDstroke *BKE_gpencil_stroke_duplicate(bGPDstroke *gps_src)
{
	bGPDstroke *gps_dst = NULL;

	gps_dst = MEM_dupallocN(gps_src);
	gps_dst->prev = gps_dst->next = NULL;

	gps_dst->points = MEM_dupallocN(gps_src->points);

	if (gps_src->dvert != NULL) {
		gps_dst->dvert = MEM_dupallocN(gps_src->dvert);
		BKE_gpencil_stroke_weights_duplicate(gps_src, gps_dst);
	}
	else {
		gps_dst->dvert = NULL;
	}

	/* Don't clear triangles, so that modifier evaluation can just use
	 * this without extra work first. Most places that need to force
	 * this data to get recalculated will destroy the data anyway though.
	 */
	gps_dst->triangles = MEM_dupallocN(gps_dst->triangles);
	/* gps_dst->flag |= GP_STROKE_RECALC_GEOMETRY; */

	/* return new stroke */
	return gps_dst;
}

/* make a copy of a given gpencil frame */
bGPDframe *BKE_gpencil_frame_duplicate(const bGPDframe *gpf_src)
{
	bGPDstroke *gps_dst = NULL;
	bGPDframe *gpf_dst;

	/* error checking */
	if (gpf_src == NULL) {
		return NULL;
	}

	/* make a copy of the source frame */
	gpf_dst = MEM_dupallocN(gpf_src);
	gpf_dst->prev = gpf_dst->next = NULL;

	/* copy strokes */
	BLI_listbase_clear(&gpf_dst->strokes);
	for (bGPDstroke *gps_src = gpf_src->strokes.first; gps_src; gps_src = gps_src->next) {
		/* make copy of source stroke */
		gps_dst = BKE_gpencil_stroke_duplicate(gps_src);
		BLI_addtail(&gpf_dst->strokes, gps_dst);
	}

	/* return new frame */
	return gpf_dst;
}

/* make a copy of strokes between gpencil frames */
void BKE_gpencil_frame_copy_strokes(bGPDframe *gpf_src, struct bGPDframe *gpf_dst)
{
	bGPDstroke *gps_dst = NULL;
	/* error checking */
	if ((gpf_src == NULL) || (gpf_dst == NULL)) {
		return;
	}

	/* copy strokes */
	BLI_listbase_clear(&gpf_dst->strokes);
	for (bGPDstroke *gps_src = gpf_src->strokes.first; gps_src; gps_src = gps_src->next) {
		/* make copy of source stroke */
		gps_dst = BKE_gpencil_stroke_duplicate(gps_src);
		BLI_addtail(&gpf_dst->strokes, gps_dst);
	}
}

/* make a copy of a given gpencil layer */
bGPDlayer *BKE_gpencil_layer_duplicate(const bGPDlayer *gpl_src)
{
	const bGPDframe *gpf_src;
	bGPDframe *gpf_dst;
	bGPDlayer *gpl_dst;

	/* error checking */
	if (gpl_src == NULL) {
		return NULL;
	}

	/* make a copy of source layer */
	gpl_dst = MEM_dupallocN(gpl_src);
	gpl_dst->prev = gpl_dst->next = NULL;

	/* copy frames */
	BLI_listbase_clear(&gpl_dst->frames);
	for (gpf_src = gpl_src->frames.first; gpf_src; gpf_src = gpf_src->next) {
		/* make a copy of source frame */
		gpf_dst = BKE_gpencil_frame_duplicate(gpf_src);
		BLI_addtail(&gpl_dst->frames, gpf_dst);

		/* if source frame was the current layer's 'active' frame, reassign that too */
		if (gpf_src == gpl_dst->actframe)
			gpl_dst->actframe = gpf_dst;
	}

	/* return new layer */
	return gpl_dst;
}

/**
 * Only copy internal data of GreasePencil ID from source to already allocated/initialized destination.
 * You probably never want to use that directly, use BKE_id_copy or BKE_id_copy_ex for typical needs.
 *
 * WARNING! This function will not handle ID user count!
 *
 * \param flag: Copying options (see BKE_library.h's LIB_ID_COPY_... flags for more).
 */
void BKE_gpencil_copy_data(bGPdata *gpd_dst, const bGPdata *gpd_src, const int UNUSED(flag))
{
	/* duplicate material array */
	if (gpd_src->mat) {
		gpd_dst->mat = MEM_dupallocN(gpd_src->mat);
	}

	/* copy layers */
	BLI_listbase_clear(&gpd_dst->layers);
	for (const bGPDlayer *gpl_src = gpd_src->layers.first; gpl_src; gpl_src = gpl_src->next) {
		/* make a copy of source layer and its data */
		bGPDlayer *gpl_dst = BKE_gpencil_layer_duplicate(gpl_src);  /* TODO here too could add unused flags... */
		BLI_addtail(&gpd_dst->layers, gpl_dst);
	}

}

/* Standard API to make a copy of GP datablock, separate from copying its data */
bGPdata *BKE_gpencil_copy(Main *bmain, const bGPdata *gpd)
{
	bGPdata *gpd_copy;
	BKE_id_copy(bmain, &gpd->id, (ID **)&gpd_copy);
	return gpd_copy;
}

/* make a copy of a given gpencil datablock */
// XXX: Should this be deprecated?
bGPdata *BKE_gpencil_data_duplicate(Main *bmain, const bGPdata *gpd_src, bool internal_copy)
{
	bGPdata *gpd_dst;

	/* Yuck and super-uber-hyper yuck!!!
	 * Should be replaceable with a no-main copy (LIB_ID_COPY_NO_MAIN etc.), but not sure about it,
	 * so for now keep old code for that one. */

	/* error checking */
	if (gpd_src == NULL) {
		return NULL;
	}

	if (internal_copy) {
		/* make a straight copy for undo buffers used during stroke drawing */
		gpd_dst = MEM_dupallocN(gpd_src);
	}
	else {
		BLI_assert(bmain != NULL);
		BKE_id_copy(bmain, &gpd_src->id, (ID **)&gpd_dst);
	}

	/* Copy internal data (layers, etc.) */
	BKE_gpencil_copy_data(gpd_dst, gpd_src, 0);

	/* return new */
	return gpd_dst;
}

void BKE_gpencil_make_local(Main *bmain, bGPdata *gpd, const bool lib_local)
{
	BKE_id_make_local_generic(bmain, &gpd->id, true, lib_local);
}

/* ************************************************** */
/* GP Stroke API */

/* ensure selection status of stroke is in sync with its points */
void BKE_gpencil_stroke_sync_selection(bGPDstroke *gps)
{
	bGPDspoint *pt;
	int i;

	/* error checking */
	if (gps == NULL)
		return;

	/* we'll stop when we find the first selected point,
	 * so initially, we must deselect
	 */
	gps->flag &= ~GP_STROKE_SELECT;

	for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
		if (pt->flag & GP_SPOINT_SELECT) {
			gps->flag |= GP_STROKE_SELECT;
			break;
		}
	}
}

/* ************************************************** */
/* GP Frame API */

/* delete the last stroke of the given frame */
void BKE_gpencil_frame_delete_laststroke(bGPDlayer *gpl, bGPDframe *gpf)
{
	bGPDstroke *gps = (gpf) ? gpf->strokes.last : NULL;
	int cfra = (gpf) ? gpf->framenum : 0; /* assume that the current frame was not locked */

	/* error checking */
	if (ELEM(NULL, gpf, gps))
		return;

	/* free the stroke and its data */
	if (gps->points) {
		MEM_freeN(gps->points);
	}
	if (gps->dvert) {
		BKE_gpencil_free_stroke_weights(gps);
		MEM_freeN(gps->dvert);
	}
	MEM_freeN(gps->triangles);
	BLI_freelinkN(&gpf->strokes, gps);

	/* if frame has no strokes after this, delete it */
	if (BLI_listbase_is_empty(&gpf->strokes)) {
		BKE_gpencil_layer_delframe(gpl, gpf);
		BKE_gpencil_layer_getframe(gpl, cfra, GP_GETFRAME_USE_PREV);
	}
}

/* ************************************************** */
/* GP Layer API */

/* Check if the given layer is able to be edited or not */
bool gpencil_layer_is_editable(const bGPDlayer *gpl)
{
	/* Sanity check */
	if (gpl == NULL)
		return false;

	/* Layer must be: Visible + Editable */
	if ((gpl->flag & (GP_LAYER_HIDE | GP_LAYER_LOCKED)) == 0) {
		/* Opacity must be sufficiently high that it is still "visible"
		 * Otherwise, it's not really "visible" to the user, so no point editing...
		 */
		if (gpl->opacity > GPENCIL_ALPHA_OPACITY_THRESH) {
			return true;
		}
	}

	/* Something failed */
	return false;
}

/* Look up the gp-frame on the requested frame number, but don't add a new one */
bGPDframe *BKE_gpencil_layer_find_frame(bGPDlayer *gpl, int cframe)
{
	bGPDframe *gpf;

	/* Search in reverse order, since this is often used for playback/adding,
	 * where it's less likely that we're interested in the earlier frames
	 */
	for (gpf = gpl->frames.last; gpf; gpf = gpf->prev) {
		if (gpf->framenum == cframe) {
			return gpf;
		}
	}

	return NULL;
}

/* get the appropriate gp-frame from a given layer
 * - this sets the layer's actframe var (if allowed to)
 * - extension beyond range (if first gp-frame is after all frame in interest and cannot add)
 */
bGPDframe *BKE_gpencil_layer_getframe(bGPDlayer *gpl, int cframe, eGP_GetFrame_Mode addnew)
{
	bGPDframe *gpf = NULL;
	short found = 0;

	/* error checking */
	if (gpl == NULL) return NULL;

	/* check if there is already an active frame */
	if (gpl->actframe) {
		gpf = gpl->actframe;

		/* do not allow any changes to layer's active frame if layer is locked from changes
		 * or if the layer has been set to stay on the current frame
		 */
		if (gpl->flag & GP_LAYER_FRAMELOCK)
			return gpf;
		/* do not allow any changes to actframe if frame has painting tag attached to it */
		if (gpf->flag & GP_FRAME_PAINT)
			return gpf;

		/* try to find matching frame */
		if (gpf->framenum < cframe) {
			for (; gpf; gpf = gpf->next) {
				if (gpf->framenum == cframe) {
					found = 1;
					break;
				}
				else if ((gpf->next) && (gpf->next->framenum > cframe)) {
					found = 1;
					break;
				}
			}

			/* set the appropriate frame */
			if (addnew) {
				if ((found) && (gpf->framenum == cframe))
					gpl->actframe = gpf;
				else if (addnew == GP_GETFRAME_ADD_COPY)
					gpl->actframe = BKE_gpencil_frame_addcopy(gpl, cframe);
				else
					gpl->actframe = BKE_gpencil_frame_addnew(gpl, cframe);
			}
			else if (found)
				gpl->actframe = gpf;
			else
				gpl->actframe = gpl->frames.last;
		}
		else {
			for (; gpf; gpf = gpf->prev) {
				if (gpf->framenum <= cframe) {
					found = 1;
					break;
				}
			}

			/* set the appropriate frame */
			if (addnew) {
				if ((found) && (gpf->framenum == cframe))
					gpl->actframe = gpf;
				else if (addnew == GP_GETFRAME_ADD_COPY)
					gpl->actframe = BKE_gpencil_frame_addcopy(gpl, cframe);
				else
					gpl->actframe = BKE_gpencil_frame_addnew(gpl, cframe);
			}
			else if (found)
				gpl->actframe = gpf;
			else
				gpl->actframe = gpl->frames.first;
		}
	}
	else if (gpl->frames.first) {
		/* check which of the ends to start checking from */
		const int first = ((bGPDframe *)(gpl->frames.first))->framenum;
		const int last = ((bGPDframe *)(gpl->frames.last))->framenum;

		if (abs(cframe - first) > abs(cframe - last)) {
			/* find gp-frame which is less than or equal to cframe */
			for (gpf = gpl->frames.last; gpf; gpf = gpf->prev) {
				if (gpf->framenum <= cframe) {
					found = 1;
					break;
				}
			}
		}
		else {
			/* find gp-frame which is less than or equal to cframe */
			for (gpf = gpl->frames.first; gpf; gpf = gpf->next) {
				if (gpf->framenum <= cframe) {
					found = 1;
					break;
				}
			}
		}

		/* set the appropriate frame */
		if (addnew) {
			if ((found) && (gpf->framenum == cframe))
				gpl->actframe = gpf;
			else
				gpl->actframe = BKE_gpencil_frame_addnew(gpl, cframe);
		}
		else if (found)
			gpl->actframe = gpf;
		else {
			/* unresolved errogenous situation! */
			CLOG_STR_ERROR(&LOG, "cannot find appropriate gp-frame");
			/* gpl->actframe should still be NULL */
		}
	}
	else {
		/* currently no frames (add if allowed to) */
		if (addnew)
			gpl->actframe = BKE_gpencil_frame_addnew(gpl, cframe);
		else {
			/* don't do anything... this may be when no frames yet! */
			/* gpl->actframe should still be NULL */
		}
	}

	/* return */
	return gpl->actframe;
}

/* delete the given frame from a layer */
bool BKE_gpencil_layer_delframe(bGPDlayer *gpl, bGPDframe *gpf)
{
	bool changed = false;

	/* error checking */
	if (ELEM(NULL, gpl, gpf))
		return false;

	/* if this frame was active, make the previous frame active instead
	 * since it's tricky to set active frame otherwise
	 */
	if (gpl->actframe == gpf)
		gpl->actframe = gpf->prev;

	/* free the frame and its data */
	changed = BKE_gpencil_free_strokes(gpf);
	BLI_freelinkN(&gpl->frames, gpf);

	return changed;
}

/* get the active gp-layer for editing */
bGPDlayer *BKE_gpencil_layer_getactive(bGPdata *gpd)
{
	bGPDlayer *gpl;

	/* error checking */
	if (ELEM(NULL, gpd, gpd->layers.first))
		return NULL;

	/* loop over layers until found (assume only one active) */
	for (gpl = gpd->layers.first; gpl; gpl = gpl->next) {
		if (gpl->flag & GP_LAYER_ACTIVE)
			return gpl;
	}

	/* no active layer found */
	return NULL;
}

/* set the active gp-layer */
void BKE_gpencil_layer_setactive(bGPdata *gpd, bGPDlayer *active)
{
	bGPDlayer *gpl;

	/* error checking */
	if (ELEM(NULL, gpd, gpd->layers.first, active))
		return;

	/* loop over layers deactivating all */
	for (gpl = gpd->layers.first; gpl; gpl = gpl->next) {
		gpl->flag &= ~GP_LAYER_ACTIVE;
		if (gpd->flag & GP_DATA_AUTOLOCK_LAYERS) {
			gpl->flag |= GP_LAYER_LOCKED;
		}
	}

	/* set as active one */
	active->flag |= GP_LAYER_ACTIVE;
	if (gpd->flag & GP_DATA_AUTOLOCK_LAYERS) {
		active->flag &= ~GP_LAYER_LOCKED;
	}
}

/* delete the active gp-layer */
void BKE_gpencil_layer_delete(bGPdata *gpd, bGPDlayer *gpl)
{
	/* error checking */
	if (ELEM(NULL, gpd, gpl))
		return;

	/* free layer */
	BKE_gpencil_free_frames(gpl);

	/* free icon providing preview of icon color */
	BKE_icon_delete(gpl->runtime.icon_id);

	BLI_freelinkN(&gpd->layers, gpl);
}

Material *BKE_gpencil_get_material_from_brush(Brush *brush)
{
	Material *ma = NULL;

	if ((brush != NULL) && (brush->gpencil_settings != NULL) &&
	    (brush->gpencil_settings->material != NULL))
	{
		ma = brush->gpencil_settings->material;
	}

	return ma;
}

/* Get active color, and add all default settings if we don't find anything */
Material *BKE_gpencil_material_ensure(Main *bmain, Object *ob)
{
	Material *ma = NULL;

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

	ma = give_current_material(ob, ob->actcol);
	if (ma == NULL) {
		if (ob->totcol == 0) {
			BKE_object_material_slot_add(bmain, ob);
		}
		ma = BKE_material_add_gpencil(bmain, DATA_("Material"));
		assign_material(bmain, ob, ma, ob->totcol, BKE_MAT_ASSIGN_USERPREF);
	}
	else if (ma->gp_style == NULL) {
		BKE_material_init_gpencil_settings(ma);
	}

	return ma;
}

/* ************************************************** */
/* GP Object - Boundbox Support */

/**
 * Get min/max coordinate bounds for single stroke
 * \return Returns whether we found any selected points
 */
bool BKE_gpencil_stroke_minmax(
        const bGPDstroke *gps, const bool use_select,
        float r_min[3], float r_max[3])
{
	const bGPDspoint *pt;
	int i;
	bool changed = false;

	if (ELEM(NULL, gps, r_min, r_max))
		return false;

	for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
		if ((use_select == false) || (pt->flag & GP_SPOINT_SELECT)) {
			minmax_v3v3_v3(r_min, r_max, &pt->x);
			changed = true;
		}
	}
	return changed;
}

/* get min/max bounds of all strokes in GP datablock */
bool BKE_gpencil_data_minmax(Object *ob, const bGPdata *gpd, float r_min[3], float r_max[3])
{
	float bmat[3][3];
	bool changed = false;

	INIT_MINMAX(r_min, r_max);

	if (gpd == NULL)
		return changed;

	for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
		bGPDframe *gpf = gpl->actframe;

		if (gpf != NULL) {
			for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
				changed = BKE_gpencil_stroke_minmax(gps, false, r_min, r_max);
			}
		}
	}

	if ((changed) && (ob)) {
		copy_m3_m4(bmat, ob->obmat);
		mul_m3_v3(bmat, r_min);
		add_v3_v3(r_min, ob->obmat[3]);
		mul_m3_v3(bmat, r_max);
		add_v3_v3(r_max, ob->obmat[3]);
	}

	return changed;
}

bool BKE_gpencil_stroke_select_check(
        const bGPDstroke *gps)
{
	const bGPDspoint *pt;
	int i;
	for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
		if (pt->flag & GP_SPOINT_SELECT) {
			return true;
		}
	}
	return false;
}

/* compute center of bounding box */
void BKE_gpencil_centroid_3d(bGPdata *gpd, float r_centroid[3])
{
	float min[3], max[3], tot[3];

	BKE_gpencil_data_minmax(NULL, gpd, min, max);

	add_v3_v3v3(tot, min, max);
	mul_v3_v3fl(r_centroid, tot, 0.5f);
}


/* create bounding box values */
static void boundbox_gpencil(Object *ob)
{
	BoundBox *bb;
	bGPdata *gpd;
	float min[3], max[3];

	if (ob->runtime.bb == NULL) {
		ob->runtime.bb = MEM_callocN(sizeof(BoundBox), "GPencil boundbox");
	}

	bb  = ob->runtime.bb;
	gpd = ob->data;

	BKE_gpencil_data_minmax(NULL, gpd, min, max);
	BKE_boundbox_init_from_minmax(bb, min, max);

	bb->flag &= ~BOUNDBOX_DIRTY;
}

/* get bounding box */
BoundBox *BKE_gpencil_boundbox_get(Object *ob)
{
	bGPdata *gpd;

	if (ELEM(NULL, ob, ob->data))
		return NULL;

	gpd = ob->data;
	if ((ob->runtime.bb) && ((ob->runtime.bb->flag & BOUNDBOX_DIRTY) == 0) &&
	    ((gpd->flag & GP_DATA_CACHE_IS_DIRTY) == 0))
	{
		return ob->runtime.bb;
	}

	boundbox_gpencil(ob);

	return ob->runtime.bb;
}

/* ************************************************** */
/* Apply Transforms */

void BKE_gpencil_transform(bGPdata *gpd, float mat[4][4])
{
	if (gpd == NULL)
		return;

	for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
		/* FIXME: For now, we just skip parented layers.
		 * Otherwise, we have to update each frame to find
		 * the current parent position/effects.
		 */
		if (gpl->parent) {
			continue;
		}

		for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
			for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
				bGPDspoint *pt;
				int i;

				for (pt = gps->points, i = 0; i < gps->totpoints; pt++, i++) {
					mul_m4_v3(mat, &pt->x);
				}

				/* TODO: Do we need to do this? distortion may mean we need to re-triangulate */
				gps->flag |= GP_STROKE_RECALC_GEOMETRY;
				gps->tot_triangles = 0;
			}
		}
	}

}

/* ************************************************** */
/* GP Object - Vertex Groups */

/* remove a vertex group */
void BKE_gpencil_vgroup_remove(Object *ob, bDeformGroup *defgroup)
{
	bGPdata *gpd = ob->data;
	MDeformVert *dvert = NULL;
	const int def_nr = BLI_findindex(&ob->defbase, defgroup);

	/* Remove points data */
	if (gpd) {
		for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
			for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
				for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
					if (gps->dvert != NULL) {
						for (int i = 0; i < gps->totpoints; i++) {
							dvert = &gps->dvert[i];
							MDeformWeight *dw = defvert_find_index(dvert, def_nr);
							if (dw != NULL) {
								defvert_remove_group(dvert, dw);
							}
							else {
								/* reorganize weights in other strokes */
								for (int g = 0; g < gps->dvert->totweight; g++) {
									dw = &dvert->dw[g];
									if ((dw != NULL) && (dw->def_nr > def_nr)) {
										dw->def_nr--;
									}
								}
							}
						}
					}
				}
			}
		}
	}

	/* Remove the group */
	BLI_freelinkN(&ob->defbase, defgroup);
	DEG_id_tag_update(&gpd->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY);
}


void BKE_gpencil_dvert_ensure(bGPDstroke *gps)
{
	if (gps->dvert == NULL) {
		gps->dvert = MEM_callocN(sizeof(MDeformVert) * gps->totpoints, "gp_stroke_weights");
	}
}

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

/**
 * Apply smooth to stroke point
 * \param gps: Stroke to smooth
 * \param i: Point index
 * \param inf: Amount of smoothing to apply
 */
bool BKE_gpencil_smooth_stroke(bGPDstroke *gps, int i, float inf)
{
	bGPDspoint *pt = &gps->points[i];
	// float pressure = 0.0f;
	float sco[3] = { 0.0f };

	/* Do nothing if not enough points to smooth out */
	if (gps->totpoints <= 2) {
		return false;
	}

	/* Only affect endpoints by a fraction of the normal strength,
	 * to prevent the stroke from shrinking too much
	 */
	if ((i == 0) || (i == gps->totpoints - 1)) {
		inf *= 0.1f;
	}

	/* Compute smoothed coordinate by taking the ones nearby */
	/* XXX: This is potentially slow, and suffers from accumulation error as earlier points are handled before later ones */
	{
		// XXX: this is hardcoded to look at 2 points on either side of the current one (i.e. 5 items total)
		const int   steps = 2;
		const float average_fac = 1.0f / (float)(steps * 2 + 1);
		int step;

		/* add the point itself */
		madd_v3_v3fl(sco, &pt->x, average_fac);

		/* n-steps before/after current point */
		// XXX: review how the endpoints are treated by this algorithm
		// XXX: falloff measures should also introduce some weighting variations, so that further-out points get less weight
		for (step = 1; step <= steps; step++) {
			bGPDspoint *pt1, *pt2;
			int before = i - step;
			int after = i + step;

			CLAMP_MIN(before, 0);
			CLAMP_MAX(after, gps->totpoints - 1);

			pt1 = &gps->points[before];
			pt2 = &gps->points[after];

			/* add both these points to the average-sum (s += p[i]/n) */
			madd_v3_v3fl(sco, &pt1->x, average_fac);
			madd_v3_v3fl(sco, &pt2->x, average_fac);

		}
	}

	/* Based on influence factor, blend between original and optimal smoothed coordinate */
	interp_v3_v3v3(&pt->x, &pt->x, sco, inf);

	return true;
}

/**
 * Apply smooth for strength to stroke point */
bool BKE_gpencil_smooth_stroke_strength(bGPDstroke *gps, int point_index, float influence)
{
	bGPDspoint *ptb = &gps->points[point_index];

	/* Do nothing if not enough points */
	if (gps->totpoints <= 2) {
		return false;
	}

	/* Compute theoretical optimal value using distances */
	bGPDspoint *pta, *ptc;
	int before = point_index - 1;
	int after = point_index + 1;

	CLAMP_MIN(before, 0);
	CLAMP_MAX(after, gps->totpoints - 1);

	pta = &gps->points[before];
	ptc = &gps->points[after];

	/* the optimal value is the corresponding to the interpolation of the strength
	 * at the distance of point b
	 */
	float fac = line_point_factor_v3(&ptb->x, &pta->x, &ptc->x);
	/* sometimes the factor can be wrong due stroke geometry, so use middle point */
	if ((fac < 0.0f) || (fac > 1.0f)) {
		fac = 0.5f;
	}
	const float optimal = (1.0f - fac) * pta->strength + fac * ptc->strength;

	/* Based on influence factor, blend between original and optimal */
	ptb->strength = (1.0f - influence) * ptb->strength + influence * optimal;

	return true;
}

/**
 * Apply smooth for thickness to stroke point (use pressure) */
bool BKE_gpencil_smooth_stroke_thickness(bGPDstroke *gps, int point_index, float influence)
{
	bGPDspoint *ptb = &gps->points[point_index];

	/* Do nothing if not enough points */
	if ((gps->totpoints <= 2) || (point_index < 1)) {
		return false;
	}

	/* Compute theoretical optimal value using distances */
	bGPDspoint *pta, *ptc;
	int before = point_index - 1;
	int after = point_index + 1;

	CLAMP_MIN(before, 0);
	CLAMP_MAX(after, gps->totpoints - 1);

	pta = &gps->points[before];
	ptc = &gps->points[after];

	/* the optimal value is the corresponding to the interpolation of the pressure
	 * at the distance of point b
	 */
	float fac = line_point_factor_v3(&ptb->x, &pta->x, &ptc->x);
	/* sometimes the factor can be wrong due stroke geometry, so use middle point */
	if ((fac < 0.0f) || (fac > 1.0f)) {
		fac = 0.5f;
	}
	float optimal = interpf(ptc->pressure, pta->pressure, fac);

	/* Based on influence factor, blend between original and optimal */
	ptb->pressure = interpf(optimal, ptb->pressure, influence);

	return true;
}

/**
 * Apply smooth for UV rotation to stroke point (use pressure).
 */
bool BKE_gpencil_smooth_stroke_uv(bGPDstroke *gps, int point_index, float influence)
{
	bGPDspoint *ptb = &gps->points[point_index];

	/* Do nothing if not enough points */
	if (gps->totpoints <= 2) {
		return false;
	}

	/* Compute theoretical optimal value */
	bGPDspoint *pta, *ptc;
	int before = point_index - 1;
	int after = point_index + 1;

	CLAMP_MIN(before, 0);
	CLAMP_MAX(after, gps->totpoints - 1);

	pta = &gps->points[before];
	ptc = &gps->points[after];

	/* the optimal value is the corresponding to the interpolation of the pressure
	 * at the distance of point b
	 */
	float fac = line_point_factor_v3(&ptb->x, &pta->x, &ptc->x);
	/* sometimes the factor can be wrong due stroke geometry, so use middle point */
	if ((fac < 0.0f) || (fac > 1.0f)) {
		fac = 0.5f;
	}
	float optimal = interpf(ptc->uv_rot, pta->uv_rot, fac);

	/* Based on influence factor, blend between original and optimal */
	ptb->uv_rot = interpf(optimal, ptb->uv_rot, influence);
	CLAMP(ptb->uv_rot, -M_PI_2, M_PI_2);

	return true;
}

/**
 * Get range of selected frames in layer.
 * Always the active frame is considered as selected, so if no more selected the range
 * will be equal to the current active frame.
 * \param gpl: Layer
 * \param r_initframe: Number of first selected frame
 * \param r_endframe: Number of last selected frame
 */
void BKE_gpencil_get_range_selected(bGPDlayer *gpl, int *r_initframe, int *r_endframe)
{
	*r_initframe = gpl->actframe->framenum;
	*r_endframe = gpl->actframe->framenum;

	for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
		if (gpf->flag & GP_FRAME_SELECT) {
			if (gpf->framenum < *r_initframe) {
				*r_initframe = gpf->framenum;
			}
			if (gpf->framenum > *r_endframe) {
				*r_endframe = gpf->framenum;
			}
		}
	}
}

/**
 * Get Falloff factor base on frame range
 * \param gpf: Frame
 * \param actnum: Number of active frame in layer
 * \param f_init: Number of first selected frame
 * \param f_end: Number of last selected frame
 * \param cur_falloff: Curve with falloff factors
 */
float BKE_gpencil_multiframe_falloff_calc(bGPDframe *gpf, int actnum, int f_init, int f_end, CurveMapping *cur_falloff)
{
	float fnum = 0.5f; /* default mid curve */
	float value;

	/* check curve is available */
	if (cur_falloff == NULL) {
		return 1.0f;
	}

	/* frames to the right of the active frame */
	if (gpf->framenum < actnum) {
		fnum = (float)(gpf->framenum - f_init) / (actnum - f_init);
		fnum *= 0.5f;
		value = curvemapping_evaluateF(cur_falloff, 0, fnum);
	}
	/* frames to the left of the active frame */
	else if (gpf->framenum > actnum) {
		fnum = (float)(gpf->framenum - actnum) / (f_end - actnum);
		fnum *= 0.5f;
		value = curvemapping_evaluateF(cur_falloff, 0, fnum + 0.5f);
	}
	else {
		value = 1.0f;
	}

	return value;
}

/* remove strokes using a material */
void BKE_gpencil_material_index_remove(bGPdata *gpd, int index)
{
	bGPDstroke *gps, *gpsn;

		for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
			for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
				for (gps = gpf->strokes.first; gps; gps = gpsn) {
					gpsn = gps->next;
					if (gps->mat_nr == index) {
						if (gps->points) {
							MEM_freeN(gps->points);
						}
						if (gps->dvert) {
							BKE_gpencil_free_stroke_weights(gps);
							MEM_freeN(gps->dvert);
						}
						if (gps->triangles) MEM_freeN(gps->triangles);
						BLI_freelinkN(&gpf->strokes, gps);
					}
					else {
						/* reassign strokes */
						if (gps->mat_nr > index) {
							gps->mat_nr--;
						}
					}
				}
			}
		}
}

void BKE_gpencil_material_remap(struct bGPdata *gpd, const unsigned int *remap, unsigned int remap_len)
{
	const short remap_len_short = (short)remap_len;

#define MAT_NR_REMAP(n) \
	if (n < remap_len_short) { \
		BLI_assert(n >= 0 && remap[n] < remap_len_short); \
		n = remap[n]; \
	} ((void)0)

	for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
		for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
			for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
				/* reassign strokes */
				MAT_NR_REMAP(gps->mat_nr);
			}
		}
	}

#undef MAT_NR_REMAP

}

/* statistics functions */
void BKE_gpencil_stats_update(bGPdata *gpd)
{
	gpd->totlayer = 0;
	gpd->totframe = 0;
	gpd->totstroke = 0;
	gpd->totpoint = 0;

	for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
		gpd->totlayer++;
		for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
			gpd->totframe++;
			for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
				gpd->totstroke++;
				gpd->totpoint += gps->totpoints;
			}
		}
	}

}

/* get material index */
int BKE_gpencil_get_material_index(Object *ob, Material *ma)
{
	short *totcol = give_totcolp(ob);
	Material *read_ma = NULL;
	for (short i = 0; i < *totcol; i++) {
		read_ma = give_current_material(ob, i + 1);
		if (ma == read_ma) {
			return i + 1;
		}
	}

	return 0;
}

/* Get points of stroke always flat to view not affected by camera view or view position */
void BKE_gpencil_stroke_2d_flat(const bGPDspoint *points, int totpoints, float(*points2d)[2], int *r_direction)
{
	BLI_assert(totpoints >= 2);

	const bGPDspoint *pt0 = &points[0];
	const bGPDspoint *pt1 = &points[1];
	const bGPDspoint *pt3 = &points[(int)(totpoints * 0.75)];

	float locx[3];
	float locy[3];
	float loc3[3];
	float normal[3];

	/* local X axis (p0 -> p1) */
	sub_v3_v3v3(locx, &pt1->x, &pt0->x);

	/* point vector at 3/4 */
	float v3[3];
	if (totpoints == 2) {
		mul_v3_v3fl(v3, &pt3->x, 0.001f);
	}
	else {
		copy_v3_v3(v3, &pt3->x);
	}

	sub_v3_v3v3(loc3, v3, &pt0->x);

	/* vector orthogonal to polygon plane */
	cross_v3_v3v3(normal, locx, loc3);

	/* local Y axis (cross to normal/x axis) */
	cross_v3_v3v3(locy, normal, locx);

	/* Normalize vectors */
	normalize_v3(locx);
	normalize_v3(locy);

	/* Get all points in local space */
	for (int i = 0; i < totpoints; i++) {
		const bGPDspoint *pt = &points[i];
		float loc[3];

		/* Get local space using first point as origin */
		sub_v3_v3v3(loc, &pt->x, &pt0->x);

		points2d[i][0] = dot_v3v3(loc, locx);
		points2d[i][1] = dot_v3v3(loc, locy);
	}

	/* Concave (-1), Convex (1), or Autodetect (0)? */
	*r_direction = (int)locy[2];
}

/* Get points of stroke always flat to view not affected by camera view or view position
 * using another stroke as reference
 */
void BKE_gpencil_stroke_2d_flat_ref(
	const bGPDspoint *ref_points, int ref_totpoints,
	const bGPDspoint *points, int totpoints,
	float(*points2d)[2], const float scale, int *r_direction)
{
	BLI_assert(totpoints >= 2);

	const bGPDspoint *pt0 = &ref_points[0];
	const bGPDspoint *pt1 = &ref_points[1];
	const bGPDspoint *pt3 = &ref_points[(int)(ref_totpoints * 0.75)];

	float locx[3];
	float locy[3];
	float loc3[3];
	float normal[3];

	/* local X axis (p0 -> p1) */
	sub_v3_v3v3(locx, &pt1->x, &pt0->x);

	/* point vector at 3/4 */
	float v3[3];
	if (totpoints == 2) {
		mul_v3_v3fl(v3, &pt3->x, 0.001f);
	}
	else {
		copy_v3_v3(v3, &pt3->x);
	}

	sub_v3_v3v3(loc3, v3, &pt0->x);

	/* vector orthogonal to polygon plane */
	cross_v3_v3v3(normal, locx, loc3);

	/* local Y axis (cross to normal/x axis) */
	cross_v3_v3v3(locy, normal, locx);

	/* Normalize vectors */
	normalize_v3(locx);
	normalize_v3(locy);

	/* Get all points in local space */
	for (int i = 0; i < totpoints; i++) {
		const bGPDspoint *pt = &points[i];
		float loc[3];
		float v1[3];
		float vn[3] = { 0.0f, 0.0f, 0.0f };

		/* apply scale to extremes of the stroke to get better collision detection
		 * the scale is divided to get more control in the UI parameter
		 */
		/* first point */
		if (i == 0) {
			const bGPDspoint *pt_next = &points[i + 1];
			sub_v3_v3v3(vn, &pt->x, &pt_next->x);
			normalize_v3(vn);
			mul_v3_fl(vn, scale / 10.0f);
			add_v3_v3v3(v1, &pt->x, vn);
		}
		/* last point */
		else if (i == totpoints - 1) {
			const bGPDspoint *pt_prev = &points[i - 1];
			sub_v3_v3v3(vn, &pt->x, &pt_prev->x);
			normalize_v3(vn);
			mul_v3_fl(vn, scale / 10.0f);
			add_v3_v3v3(v1, &pt->x, vn);
		}
		else {
			copy_v3_v3(v1, &pt->x);
		}

		/* Get local space using first point as origin (ref stroke) */
		sub_v3_v3v3(loc, v1, &pt0->x);

		points2d[i][0] = dot_v3v3(loc, locx);
		points2d[i][1] = dot_v3v3(loc, locy);
	}

	/* Concave (-1), Convex (1), or Autodetect (0)? */
	*r_direction = (int)locy[2];
}