/*
 * ***** 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) 2005 by the Blender Foundation.
 * All rights reserved.
 *
 * Contributor(s): Daniel Dunbar
 *                 Ton Roosendaal,
 *                 Ben Batt,
 *                 Brecht Van Lommel,
 *                 Campbell Barton
 *
 * ***** END GPL LICENSE BLOCK *****
 *
 */

/** \file blender/modifiers/intern/MOD_explode.c
 *  \ingroup modifiers
 */


#include "DNA_meshdata_types.h"
#include "DNA_scene_types.h"
#include "DNA_object_types.h"

#include "BLI_utildefines.h"
#include "BLI_kdtree.h"
#include "BLI_rand.h"
#include "BLI_math.h"
#include "BLI_edgehash.h"

#include "BKE_cdderivedmesh.h"
#include "BKE_deform.h"
#include "BKE_lattice.h"
#include "BKE_mesh.h"
#include "BKE_modifier.h"
#include "BKE_particle.h"
#include "BKE_scene.h"

#include "MEM_guardedalloc.h"

#include "MOD_modifiertypes.h"

static void initData(ModifierData *md)
{
	ExplodeModifierData *emd = (ExplodeModifierData *) md;

	emd->facepa = NULL;
	emd->flag |= eExplodeFlag_Unborn + eExplodeFlag_Alive + eExplodeFlag_Dead;
}
static void freeData(ModifierData *md)
{
	ExplodeModifierData *emd = (ExplodeModifierData *) md;
	
	if (emd->facepa) MEM_freeN(emd->facepa);
}
static void copyData(ModifierData *md, ModifierData *target)
{
#if 0
	ExplodeModifierData *emd = (ExplodeModifierData *) md;
#endif
	ExplodeModifierData *temd = (ExplodeModifierData *) target;

	modifier_copyData_generic(md, target);

	temd->facepa = NULL;
}
static bool dependsOnTime(ModifierData *UNUSED(md))
{
	return true;
}
static CustomDataMask requiredDataMask(Object *UNUSED(ob), ModifierData *md)
{
	ExplodeModifierData *emd = (ExplodeModifierData *) md;
	CustomDataMask dataMask = 0;

	if (emd->vgroup)
		dataMask |= CD_MASK_MDEFORMVERT;

	return dataMask;
}

static void createFacepa(ExplodeModifierData *emd,
                         ParticleSystemModifierData *psmd,
                         DerivedMesh *dm)
{
	ParticleSystem *psys = psmd->psys;
	MFace *fa = NULL, *mface = NULL;
	MVert *mvert = NULL;
	ParticleData *pa;
	KDTree *tree;
	RNG *rng;
	float center[3], co[3];
	int *facepa = NULL, *vertpa = NULL, totvert = 0, totface = 0, totpart = 0;
	int i, p, v1, v2, v3, v4 = 0;

	mvert = dm->getVertArray(dm);
	mface = dm->getTessFaceArray(dm);
	totface = dm->getNumTessFaces(dm);
	totvert = dm->getNumVerts(dm);
	totpart = psmd->psys->totpart;

	rng = BLI_rng_new_srandom(psys->seed);

	if (emd->facepa)
		MEM_freeN(emd->facepa);

	facepa = emd->facepa = MEM_calloc_arrayN(totface, sizeof(int), "explode_facepa");

	vertpa = MEM_calloc_arrayN(totvert, sizeof(int), "explode_vertpa");

	/* initialize all faces & verts to no particle */
	for (i = 0; i < totface; i++)
		facepa[i] = totpart;

	for (i = 0; i < totvert; i++)
		vertpa[i] = totpart;

	/* set protected verts */
	if (emd->vgroup) {
		MDeformVert *dvert = dm->getVertDataArray(dm, CD_MDEFORMVERT);
		if (dvert) {
			const int defgrp_index = emd->vgroup - 1;
			for (i = 0; i < totvert; i++, dvert++) {
				float val = BLI_rng_get_float(rng);
				val = (1.0f - emd->protect) * val + emd->protect * 0.5f;
				if (val < defvert_find_weight(dvert, defgrp_index))
					vertpa[i] = -1;
			}
		}
	}

	/* make tree of emitter locations */
	tree = BLI_kdtree_new(totpart);
	for (p = 0, pa = psys->particles; p < totpart; p++, pa++) {
		psys_particle_on_emitter(psmd, psys->part->from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, co, NULL, NULL, NULL, NULL, NULL);
		BLI_kdtree_insert(tree, p, co);
	}
	BLI_kdtree_balance(tree);

	/* set face-particle-indexes to nearest particle to face center */
	for (i = 0, fa = mface; i < totface; i++, fa++) {
		add_v3_v3v3(center, mvert[fa->v1].co, mvert[fa->v2].co);
		add_v3_v3(center, mvert[fa->v3].co);
		if (fa->v4) {
			add_v3_v3(center, mvert[fa->v4].co);
			mul_v3_fl(center, 0.25);
		}
		else
			mul_v3_fl(center, 1.0f / 3.0f);

		p = BLI_kdtree_find_nearest(tree, center, NULL);

		v1 = vertpa[fa->v1];
		v2 = vertpa[fa->v2];
		v3 = vertpa[fa->v3];
		if (fa->v4)
			v4 = vertpa[fa->v4];

		if (v1 >= 0 && v2 >= 0 && v3 >= 0 && (fa->v4 == 0 || v4 >= 0))
			facepa[i] = p;

		if (v1 >= 0) vertpa[fa->v1] = p;
		if (v2 >= 0) vertpa[fa->v2] = p;
		if (v3 >= 0) vertpa[fa->v3] = p;
		if (fa->v4 && v4 >= 0) vertpa[fa->v4] = p;
	}

	if (vertpa) MEM_freeN(vertpa);
	BLI_kdtree_free(tree);

	BLI_rng_free(rng);
}

static int edgecut_get(EdgeHash *edgehash, unsigned int v1, unsigned int v2)
{
	return GET_INT_FROM_POINTER(BLI_edgehash_lookup(edgehash, v1, v2));
}

 
static const short add_faces[24] = {
	0,
	0, 0, 2, 0, 1, 2, 2, 0, 2, 1,
	2, 2, 2, 2, 3, 0, 0, 0, 1, 0,
	1, 1, 2
};

static MFace *get_dface(DerivedMesh *dm, DerivedMesh *split, int cur, int i, MFace *mf)
{
	MFace *df = CDDM_get_tessface(split, cur);
	DM_copy_tessface_data(dm, split, i, cur, 1);
	*df = *mf;
	return df;
}

#define SET_VERTS(a, b, c, d)           \
	{                                   \
		v[0] = mf->v##a; uv[0] = a - 1; \
		v[1] = mf->v##b; uv[1] = b - 1; \
		v[2] = mf->v##c; uv[2] = c - 1; \
		v[3] = mf->v##d; uv[3] = d - 1; \
	} (void)0

#define GET_ES(v1, v2) edgecut_get(eh, v1, v2)
#define INT_UV(uvf, c0, c1) mid_v2_v2v2(uvf, mf->uv[c0], mf->uv[c1])

static void remap_faces_3_6_9_12(DerivedMesh *dm, DerivedMesh *split, MFace *mf, int *facepa, int *vertpa, int i, EdgeHash *eh, int cur, int v1, int v2, int v3, int v4)
{
	MFace *df1 = get_dface(dm, split, cur, i, mf);
	MFace *df2 = get_dface(dm, split, cur + 1, i, mf);
	MFace *df3 = get_dface(dm, split, cur + 2, i, mf);

	facepa[cur] = vertpa[v1];
	df1->v1 = v1;
	df1->v2 = GET_ES(v1, v2);
	df1->v3 = GET_ES(v2, v3);
	df1->v4 = v3;
	df1->flag |= ME_FACE_SEL;

	facepa[cur + 1] = vertpa[v2];
	df2->v1 = GET_ES(v1, v2);
	df2->v2 = v2;
	df2->v3 = GET_ES(v2, v3);
	df2->v4 = 0;
	df2->flag &= ~ME_FACE_SEL;

	facepa[cur + 2] = vertpa[v1];
	df3->v1 = v1;
	df3->v2 = v3;
	df3->v3 = v4;
	df3->v4 = 0;
	df3->flag &= ~ME_FACE_SEL;
}

static void remap_uvs_3_6_9_12(DerivedMesh *dm, DerivedMesh *split, int numlayer, int i, int cur, int c0, int c1, int c2, int c3)
{
	MTFace *mf, *df1, *df2, *df3;
	int l;

	for (l = 0; l < numlayer; l++) {
		mf = CustomData_get_layer_n(&split->faceData, CD_MTFACE, l);
		df1 = mf + cur;
		df2 = df1 + 1;
		df3 = df1 + 2;
		mf = CustomData_get_layer_n(&dm->faceData, CD_MTFACE, l);
		mf += i;

		copy_v2_v2(df1->uv[0], mf->uv[c0]);
		INT_UV(df1->uv[1], c0, c1);
		INT_UV(df1->uv[2], c1, c2);
		copy_v2_v2(df1->uv[3], mf->uv[c2]);

		INT_UV(df2->uv[0], c0, c1);
		copy_v2_v2(df2->uv[1], mf->uv[c1]);
		INT_UV(df2->uv[2], c1, c2);

		copy_v2_v2(df3->uv[0], mf->uv[c0]);
		copy_v2_v2(df3->uv[1], mf->uv[c2]);
		copy_v2_v2(df3->uv[2], mf->uv[c3]);
	}
}

static void remap_faces_5_10(DerivedMesh *dm, DerivedMesh *split, MFace *mf, int *facepa, int *vertpa, int i, EdgeHash *eh, int cur, int v1, int v2, int v3, int v4)
{
	MFace *df1 = get_dface(dm, split, cur, i, mf);
	MFace *df2 = get_dface(dm, split, cur + 1, i, mf);

	facepa[cur] = vertpa[v1];
	df1->v1 = v1;
	df1->v2 = v2;
	df1->v3 = GET_ES(v2, v3);
	df1->v4 = GET_ES(v1, v4);
	df1->flag |= ME_FACE_SEL;

	facepa[cur + 1] = vertpa[v3];
	df2->v1 = GET_ES(v1, v4);
	df2->v2 = GET_ES(v2, v3);
	df2->v3 = v3;
	df2->v4 = v4;
	df2->flag |= ME_FACE_SEL;
}

static void remap_uvs_5_10(DerivedMesh *dm, DerivedMesh *split, int numlayer, int i, int cur, int c0, int c1, int c2, int c3)
{
	MTFace *mf, *df1, *df2;
	int l;

	for (l = 0; l < numlayer; l++) {
		mf = CustomData_get_layer_n(&split->faceData, CD_MTFACE, l);
		df1 = mf + cur;
		df2 = df1 + 1;
		mf = CustomData_get_layer_n(&dm->faceData, CD_MTFACE, l);
		mf += i;

		copy_v2_v2(df1->uv[0], mf->uv[c0]);
		copy_v2_v2(df1->uv[1], mf->uv[c1]);
		INT_UV(df1->uv[2], c1, c2);
		INT_UV(df1->uv[3], c0, c3);

		INT_UV(df2->uv[0], c0, c3);
		INT_UV(df2->uv[1], c1, c2);
		copy_v2_v2(df2->uv[2], mf->uv[c2]);
		copy_v2_v2(df2->uv[3], mf->uv[c3]);

	}
}

static void remap_faces_15(DerivedMesh *dm, DerivedMesh *split, MFace *mf, int *facepa, int *vertpa, int i, EdgeHash *eh, int cur, int v1, int v2, int v3, int v4)
{
	MFace *df1 = get_dface(dm, split, cur, i, mf);
	MFace *df2 = get_dface(dm, split, cur + 1, i, mf);
	MFace *df3 = get_dface(dm, split, cur + 2, i, mf);
	MFace *df4 = get_dface(dm, split, cur + 3, i, mf);

	facepa[cur] = vertpa[v1];
	df1->v1 = v1;
	df1->v2 = GET_ES(v1, v2);
	df1->v3 = GET_ES(v1, v3);
	df1->v4 = GET_ES(v1, v4);
	df1->flag |= ME_FACE_SEL;

	facepa[cur + 1] = vertpa[v2];
	df2->v1 = GET_ES(v1, v2);
	df2->v2 = v2;
	df2->v3 = GET_ES(v2, v3);
	df2->v4 = GET_ES(v1, v3);
	df2->flag |= ME_FACE_SEL;

	facepa[cur + 2] = vertpa[v3];
	df3->v1 = GET_ES(v1, v3);
	df3->v2 = GET_ES(v2, v3);
	df3->v3 = v3;
	df3->v4 = GET_ES(v3, v4);
	df3->flag |= ME_FACE_SEL;

	facepa[cur + 3] = vertpa[v4];
	df4->v1 = GET_ES(v1, v4);
	df4->v2 = GET_ES(v1, v3);
	df4->v3 = GET_ES(v3, v4);
	df4->v4 = v4;
	df4->flag |= ME_FACE_SEL;
}

static void remap_uvs_15(DerivedMesh *dm, DerivedMesh *split, int numlayer, int i, int cur, int c0, int c1, int c2, int c3)
{
	MTFace *mf, *df1, *df2, *df3, *df4;
	int l;

	for (l = 0; l < numlayer; l++) {
		mf = CustomData_get_layer_n(&split->faceData, CD_MTFACE, l);
		df1 = mf + cur;
		df2 = df1 + 1;
		df3 = df1 + 2;
		df4 = df1 + 3;
		mf = CustomData_get_layer_n(&dm->faceData, CD_MTFACE, l);
		mf += i;

		copy_v2_v2(df1->uv[0], mf->uv[c0]);
		INT_UV(df1->uv[1], c0, c1);
		INT_UV(df1->uv[2], c0, c2);
		INT_UV(df1->uv[3], c0, c3);

		INT_UV(df2->uv[0], c0, c1);
		copy_v2_v2(df2->uv[1], mf->uv[c1]);
		INT_UV(df2->uv[2], c1, c2);
		INT_UV(df2->uv[3], c0, c2);

		INT_UV(df3->uv[0], c0, c2);
		INT_UV(df3->uv[1], c1, c2);
		copy_v2_v2(df3->uv[2], mf->uv[c2]);
		INT_UV(df3->uv[3], c2, c3);

		INT_UV(df4->uv[0], c0, c3);
		INT_UV(df4->uv[1], c0, c2);
		INT_UV(df4->uv[2], c2, c3);
		copy_v2_v2(df4->uv[3], mf->uv[c3]);
	}
}

static void remap_faces_7_11_13_14(DerivedMesh *dm, DerivedMesh *split, MFace *mf, int *facepa, int *vertpa, int i, EdgeHash *eh, int cur, int v1, int v2, int v3, int v4)
{
	MFace *df1 = get_dface(dm, split, cur, i, mf);
	MFace *df2 = get_dface(dm, split, cur + 1, i, mf);
	MFace *df3 = get_dface(dm, split, cur + 2, i, mf);

	facepa[cur] = vertpa[v1];
	df1->v1 = v1;
	df1->v2 = GET_ES(v1, v2);
	df1->v3 = GET_ES(v2, v3);
	df1->v4 = GET_ES(v1, v4);
	df1->flag |= ME_FACE_SEL;

	facepa[cur + 1] = vertpa[v2];
	df2->v1 = GET_ES(v1, v2);
	df2->v2 = v2;
	df2->v3 = GET_ES(v2, v3);
	df2->v4 = 0;
	df2->flag &= ~ME_FACE_SEL;

	facepa[cur + 2] = vertpa[v4];
	df3->v1 = GET_ES(v1, v4);
	df3->v2 = GET_ES(v2, v3);
	df3->v3 = v3;
	df3->v4 = v4;
	df3->flag |= ME_FACE_SEL;
}

static void remap_uvs_7_11_13_14(DerivedMesh *dm, DerivedMesh *split, int numlayer, int i, int cur, int c0, int c1, int c2, int c3)
{
	MTFace *mf, *df1, *df2, *df3;
	int l;

	for (l = 0; l < numlayer; l++) {
		mf = CustomData_get_layer_n(&split->faceData, CD_MTFACE, l);
		df1 = mf + cur;
		df2 = df1 + 1;
		df3 = df1 + 2;
		mf = CustomData_get_layer_n(&dm->faceData, CD_MTFACE, l);
		mf += i;

		copy_v2_v2(df1->uv[0], mf->uv[c0]);
		INT_UV(df1->uv[1], c0, c1);
		INT_UV(df1->uv[2], c1, c2);
		INT_UV(df1->uv[3], c0, c3);

		INT_UV(df2->uv[0], c0, c1);
		copy_v2_v2(df2->uv[1], mf->uv[c1]);
		INT_UV(df2->uv[2], c1, c2);

		INT_UV(df3->uv[0], c0, c3);
		INT_UV(df3->uv[1], c1, c2);
		copy_v2_v2(df3->uv[2], mf->uv[c2]);
		copy_v2_v2(df3->uv[3], mf->uv[c3]);
	}
}

static void remap_faces_19_21_22(DerivedMesh *dm, DerivedMesh *split, MFace *mf, int *facepa, int *vertpa, int i, EdgeHash *eh, int cur, int v1, int v2, int v3)
{
	MFace *df1 = get_dface(dm, split, cur, i, mf);
	MFace *df2 = get_dface(dm, split, cur + 1, i, mf);

	facepa[cur] = vertpa[v1];
	df1->v1 = v1;
	df1->v2 = GET_ES(v1, v2);
	df1->v3 = GET_ES(v1, v3);
	df1->v4 = 0;
	df1->flag &= ~ME_FACE_SEL;

	facepa[cur + 1] = vertpa[v2];
	df2->v1 = GET_ES(v1, v2);
	df2->v2 = v2;
	df2->v3 = v3;
	df2->v4 = GET_ES(v1, v3);
	df2->flag |= ME_FACE_SEL;
}

static void remap_uvs_19_21_22(DerivedMesh *dm, DerivedMesh *split, int numlayer, int i, int cur, int c0, int c1, int c2)
{
	MTFace *mf, *df1, *df2;
	int l;

	for (l = 0; l < numlayer; l++) {
		mf = CustomData_get_layer_n(&split->faceData, CD_MTFACE, l);
		df1 = mf + cur;
		df2 = df1 + 1;
		mf = CustomData_get_layer_n(&dm->faceData, CD_MTFACE, l);
		mf += i;

		copy_v2_v2(df1->uv[0], mf->uv[c0]);
		INT_UV(df1->uv[1], c0, c1);
		INT_UV(df1->uv[2], c0, c2);

		INT_UV(df2->uv[0], c0, c1);
		copy_v2_v2(df2->uv[1], mf->uv[c1]);
		copy_v2_v2(df2->uv[2], mf->uv[c2]);
		INT_UV(df2->uv[3], c0, c2);
	}
}

static void remap_faces_23(DerivedMesh *dm, DerivedMesh *split, MFace *mf, int *facepa, int *vertpa, int i, EdgeHash *eh, int cur, int v1, int v2, int v3)
{
	MFace *df1 = get_dface(dm, split, cur, i, mf);
	MFace *df2 = get_dface(dm, split, cur + 1, i, mf);
	MFace *df3 = get_dface(dm, split, cur + 2, i, mf);

	facepa[cur] = vertpa[v1];
	df1->v1 = v1;
	df1->v2 = GET_ES(v1, v2);
	df1->v3 = GET_ES(v2, v3);
	df1->v4 = GET_ES(v1, v3);
	df1->flag |= ME_FACE_SEL;

	facepa[cur + 1] = vertpa[v2];
	df2->v1 = GET_ES(v1, v2);
	df2->v2 = v2;
	df2->v3 = GET_ES(v2, v3);
	df2->v4 = 0;
	df2->flag &= ~ME_FACE_SEL;

	facepa[cur + 2] = vertpa[v3];
	df3->v1 = GET_ES(v1, v3);
	df3->v2 = GET_ES(v2, v3);
	df3->v3 = v3;
	df3->v4 = 0;
	df3->flag &= ~ME_FACE_SEL;
}

static void remap_uvs_23(DerivedMesh *dm, DerivedMesh *split, int numlayer, int i, int cur, int c0, int c1, int c2)
{
	MTFace *mf, *df1, *df2;
	int l;

	for (l = 0; l < numlayer; l++) {
		mf = CustomData_get_layer_n(&split->faceData, CD_MTFACE, l);
		df1 = mf + cur;
		df2 = df1 + 1;
		mf = CustomData_get_layer_n(&dm->faceData, CD_MTFACE, l);
		mf += i;

		copy_v2_v2(df1->uv[0], mf->uv[c0]);
		INT_UV(df1->uv[1], c0, c1);
		INT_UV(df1->uv[2], c1, c2);
		INT_UV(df1->uv[3], c0, c2);

		INT_UV(df2->uv[0], c0, c1);
		copy_v2_v2(df2->uv[1], mf->uv[c1]);
		INT_UV(df2->uv[2], c1, c2);

		INT_UV(df2->uv[0], c0, c2);
		INT_UV(df2->uv[1], c1, c2);
		copy_v2_v2(df2->uv[2], mf->uv[c2]);
	}
}

static DerivedMesh *cutEdges(ExplodeModifierData *emd, DerivedMesh *dm)
{
	DerivedMesh *splitdm;
	MFace *mf = NULL, *df1 = NULL;
	MFace *mface = dm->getTessFaceArray(dm);
	MVert *dupve, *mv;
	EdgeHash *edgehash;
	EdgeHashIterator *ehi;
	int totvert = dm->getNumVerts(dm);
	int totface = dm->getNumTessFaces(dm);

	int *facesplit = MEM_calloc_arrayN(totface, sizeof(int), "explode_facesplit");
	int *vertpa = MEM_calloc_arrayN(totvert, sizeof(int), "explode_vertpa2");
	int *facepa = emd->facepa;
	int *fs, totesplit = 0, totfsplit = 0, curdupface = 0;
	int i, v1, v2, v3, v4, esplit,
	    v[4]  = {0, 0, 0, 0}, /* To quite gcc barking... */
	    uv[4] = {0, 0, 0, 0}; /* To quite gcc barking... */
	int numlayer;
	unsigned int ed_v1, ed_v2;

	edgehash = BLI_edgehash_new(__func__);

	/* recreate vertpa from facepa calculation */
	for (i = 0, mf = mface; i < totface; i++, mf++) {
		vertpa[mf->v1] = facepa[i];
		vertpa[mf->v2] = facepa[i];
		vertpa[mf->v3] = facepa[i];
		if (mf->v4)
			vertpa[mf->v4] = facepa[i];
	}

	/* mark edges for splitting and how to split faces */
	for (i = 0, mf = mface, fs = facesplit; i < totface; i++, mf++, fs++) {
		v1 = vertpa[mf->v1];
		v2 = vertpa[mf->v2];
		v3 = vertpa[mf->v3];

		if (v1 != v2) {
			BLI_edgehash_reinsert(edgehash, mf->v1, mf->v2, NULL);
			(*fs) |= 1;
		}

		if (v2 != v3) {
			BLI_edgehash_reinsert(edgehash, mf->v2, mf->v3, NULL);
			(*fs) |= 2;
		}

		if (mf->v4) {
			v4 = vertpa[mf->v4];

			if (v3 != v4) {
				BLI_edgehash_reinsert(edgehash, mf->v3, mf->v4, NULL);
				(*fs) |= 4;
			}

			if (v1 != v4) {
				BLI_edgehash_reinsert(edgehash, mf->v1, mf->v4, NULL);
				(*fs) |= 8;
			}

			/* mark center vertex as a fake edge split */
			if (*fs == 15)
				BLI_edgehash_reinsert(edgehash, mf->v1, mf->v3, NULL);
		}
		else {
			(*fs) |= 16; /* mark face as tri */

			if (v1 != v3) {
				BLI_edgehash_reinsert(edgehash, mf->v1, mf->v3, NULL);
				(*fs) |= 4;
			}
		}
	}

	/* count splits & create indexes for new verts */
	ehi = BLI_edgehashIterator_new(edgehash);
	totesplit = totvert;
	for (; !BLI_edgehashIterator_isDone(ehi); BLI_edgehashIterator_step(ehi)) {
		BLI_edgehashIterator_setValue(ehi, SET_INT_IN_POINTER(totesplit));
		totesplit++;
	}
	BLI_edgehashIterator_free(ehi);

	/* count new faces due to splitting */
	for (i = 0, fs = facesplit; i < totface; i++, fs++)
		totfsplit += add_faces[*fs];
	
	splitdm = CDDM_from_template_ex(
	        dm, totesplit, 0, totface + totfsplit, 0, 0,
	        CD_MASK_DERIVEDMESH | CD_MASK_FACECORNERS);
	numlayer = CustomData_number_of_layers(&splitdm->faceData, CD_MTFACE);

	/* copy new faces & verts (is it really this painful with custom data??) */
	for (i = 0; i < totvert; i++) {
		MVert source;
		MVert *dest;
		dm->getVert(dm, i, &source);
		dest = CDDM_get_vert(splitdm, i);

		DM_copy_vert_data(dm, splitdm, i, i, 1);
		*dest = source;
	}

	/* override original facepa (original pointer is saved in caller function) */

	/* BMESH_TODO, (totfsplit * 2) over allocation is used since the quads are
	 * later interpreted as tri's, for this to work right I think we probably
	 * have to stop using tessface - campbell */

	facepa = MEM_calloc_arrayN((totface + (totfsplit * 2)), sizeof(int), "explode_facepa");
	//memcpy(facepa, emd->facepa, totface*sizeof(int));
	emd->facepa = facepa;

	/* create new verts */
	ehi = BLI_edgehashIterator_new(edgehash);
	for (; !BLI_edgehashIterator_isDone(ehi); BLI_edgehashIterator_step(ehi)) {
		BLI_edgehashIterator_getKey(ehi, &ed_v1, &ed_v2);
		esplit = GET_INT_FROM_POINTER(BLI_edgehashIterator_getValue(ehi));
		mv = CDDM_get_vert(splitdm, ed_v2);
		dupve = CDDM_get_vert(splitdm, esplit);

		DM_copy_vert_data(splitdm, splitdm, ed_v2, esplit, 1);

		*dupve = *mv;

		mv = CDDM_get_vert(splitdm, ed_v1);

		mid_v3_v3v3(dupve->co, dupve->co, mv->co);
	}
	BLI_edgehashIterator_free(ehi);

	/* create new faces */
	curdupface = 0; //=totface;
	//curdupin=totesplit;
	for (i = 0, fs = facesplit; i < totface; i++, fs++) {
		mf = dm->getTessFaceData(dm, i, CD_MFACE);

		switch (*fs) {
			case 3:
			case 10:
			case 11:
			case 15:
				SET_VERTS(1, 2, 3, 4);
				break;
			case 5:
			case 6:
			case 7:
				SET_VERTS(2, 3, 4, 1);
				break;
			case 9:
			case 13:
				SET_VERTS(4, 1, 2, 3);
				break;
			case 12:
			case 14:
				SET_VERTS(3, 4, 1, 2);
				break;
			case 21:
			case 23:
				SET_VERTS(1, 2, 3, 4);
				break;
			case 19:
				SET_VERTS(2, 3, 1, 4);
				break;
			case 22:
				SET_VERTS(3, 1, 2, 4);
				break;
		}

		switch (*fs) {
			case 3:
			case 6:
			case 9:
			case 12:
				remap_faces_3_6_9_12(dm, splitdm, mf, facepa, vertpa, i, edgehash, curdupface, v[0], v[1], v[2], v[3]);
				if (numlayer)
					remap_uvs_3_6_9_12(dm, splitdm, numlayer, i, curdupface, uv[0], uv[1], uv[2], uv[3]);
				break;
			case 5:
			case 10:
				remap_faces_5_10(dm, splitdm, mf, facepa, vertpa, i, edgehash, curdupface, v[0], v[1], v[2], v[3]);
				if (numlayer)
					remap_uvs_5_10(dm, splitdm, numlayer, i, curdupface, uv[0], uv[1], uv[2], uv[3]);
				break;
			case 15:
				remap_faces_15(dm, splitdm, mf, facepa, vertpa, i, edgehash, curdupface, v[0], v[1], v[2], v[3]);
				if (numlayer)
					remap_uvs_15(dm, splitdm, numlayer, i, curdupface, uv[0], uv[1], uv[2], uv[3]);
				break;
			case 7:
			case 11:
			case 13:
			case 14:
				remap_faces_7_11_13_14(dm, splitdm, mf, facepa, vertpa, i, edgehash, curdupface, v[0], v[1], v[2], v[3]);
				if (numlayer)
					remap_uvs_7_11_13_14(dm, splitdm, numlayer, i, curdupface, uv[0], uv[1], uv[2], uv[3]);
				break;
			case 19:
			case 21:
			case 22:
				remap_faces_19_21_22(dm, splitdm, mf, facepa, vertpa, i, edgehash, curdupface, v[0], v[1], v[2]);
				if (numlayer)
					remap_uvs_19_21_22(dm, splitdm, numlayer, i, curdupface, uv[0], uv[1], uv[2]);
				break;
			case 23:
				remap_faces_23(dm, splitdm, mf, facepa, vertpa, i, edgehash, curdupface, v[0], v[1], v[2]);
				if (numlayer)
					remap_uvs_23(dm, splitdm, numlayer, i, curdupface, uv[0], uv[1], uv[2]);
				break;
			case 0:
			case 16:
				df1 = get_dface(dm, splitdm, curdupface, i, mf);
				facepa[curdupface] = vertpa[mf->v1];

				if (df1->v4)
					df1->flag |= ME_FACE_SEL;
				else
					df1->flag &= ~ME_FACE_SEL;
				break;
		}

		curdupface += add_faces[*fs] + 1;
	}

	for (i = 0; i < curdupface; i++) {
		mf = CDDM_get_tessface(splitdm, i);
		test_index_face(mf, &splitdm->faceData, i, ((mf->flag & ME_FACE_SEL) ? 4 : 3));
	}

	BLI_edgehash_free(edgehash, NULL);
	MEM_freeN(facesplit);
	MEM_freeN(vertpa);

	CDDM_calc_edges_tessface(splitdm);
	CDDM_tessfaces_to_faces(splitdm); /*builds ngon faces from tess (mface) faces*/

	return splitdm;
}
static DerivedMesh *explodeMesh(ExplodeModifierData *emd,
                                ParticleSystemModifierData *psmd, Scene *scene, Object *ob,
                                DerivedMesh *to_explode)
{
	DerivedMesh *explode, *dm = to_explode;
	MFace *mf = NULL, *mface;
	/* ParticleSettings *part=psmd->psys->part; */ /* UNUSED */
	ParticleSimulationData sim = {NULL};
	ParticleData *pa = NULL, *pars = psmd->psys->particles;
	ParticleKey state, birth;
	EdgeHash *vertpahash;
	EdgeHashIterator *ehi;
	float *vertco = NULL, imat[4][4];
	float rot[4];
	float cfra;
	/* float timestep; */
	const int *facepa = emd->facepa;
	int totdup = 0, totvert = 0, totface = 0, totpart = 0, delface = 0;
	int i, v, u;
	unsigned int ed_v1, ed_v2, mindex = 0;
	MTFace *mtface = NULL, *mtf;

	totface = dm->getNumTessFaces(dm);
	totvert = dm->getNumVerts(dm);
	mface = dm->getTessFaceArray(dm);
	totpart = psmd->psys->totpart;

	sim.scene = scene;
	sim.ob = ob;
	sim.psys = psmd->psys;
	sim.psmd = psmd;

	/* timestep = psys_get_timestep(&sim); */

	cfra = BKE_scene_frame_get(scene);

	/* hash table for vertice <-> particle relations */
	vertpahash = BLI_edgehash_new(__func__);

	for (i = 0; i < totface; i++) {
		if (facepa[i] != totpart) {
			pa = pars + facepa[i];

			if ((pa->alive == PARS_UNBORN && (emd->flag & eExplodeFlag_Unborn) == 0) ||
			    (pa->alive == PARS_ALIVE && (emd->flag & eExplodeFlag_Alive) == 0) ||
			    (pa->alive == PARS_DEAD && (emd->flag & eExplodeFlag_Dead) == 0))
			{
				delface++;
				continue;
			}
		}

		/* do mindex + totvert to ensure the vertex index to be the first
		 * with BLI_edgehashIterator_getKey */
		if (facepa[i] == totpart || cfra < (pars + facepa[i])->time)
			mindex = totvert + totpart;
		else 
			mindex = totvert + facepa[i];

		mf = &mface[i];

		/* set face vertices to exist in particle group */
		BLI_edgehash_reinsert(vertpahash, mf->v1, mindex, NULL);
		BLI_edgehash_reinsert(vertpahash, mf->v2, mindex, NULL);
		BLI_edgehash_reinsert(vertpahash, mf->v3, mindex, NULL);
		if (mf->v4)
			BLI_edgehash_reinsert(vertpahash, mf->v4, mindex, NULL);
	}

	/* make new vertice indexes & count total vertices after duplication */
	ehi = BLI_edgehashIterator_new(vertpahash);
	for (; !BLI_edgehashIterator_isDone(ehi); BLI_edgehashIterator_step(ehi)) {
		BLI_edgehashIterator_setValue(ehi, SET_INT_IN_POINTER(totdup));
		totdup++;
	}
	BLI_edgehashIterator_free(ehi);

	/* the final duplicated vertices */
	explode = CDDM_from_template_ex(dm, totdup, 0, totface - delface, 0, 0, CD_MASK_DERIVEDMESH | CD_MASK_FACECORNERS);
	mtface = CustomData_get_layer_named(&explode->faceData, CD_MTFACE, emd->uvname);
	/*dupvert = CDDM_get_verts(explode);*/

	/* getting back to object space */
	invert_m4_m4(imat, ob->obmat);

	psmd->psys->lattice_deform_data = psys_create_lattice_deform_data(&sim);

	/* duplicate & displace vertices */
	ehi = BLI_edgehashIterator_new(vertpahash);
	for (; !BLI_edgehashIterator_isDone(ehi); BLI_edgehashIterator_step(ehi)) {
		MVert source;
		MVert *dest;

		/* get particle + vertex from hash */
		BLI_edgehashIterator_getKey(ehi, &ed_v1, &ed_v2);
		ed_v2 -= totvert;
		v = GET_INT_FROM_POINTER(BLI_edgehashIterator_getValue(ehi));

		dm->getVert(dm, ed_v1, &source);
		dest = CDDM_get_vert(explode, v);

		DM_copy_vert_data(dm, explode, ed_v1, v, 1);
		*dest = source;

		if (ed_v2 != totpart) {
			/* get particle */
			pa = pars + ed_v2;

			psys_get_birth_coords(&sim, pa, &birth, 0, 0);

			state.time = cfra;
			psys_get_particle_state(&sim, ed_v2, &state, 1);

			vertco = CDDM_get_vert(explode, v)->co;
			mul_m4_v3(ob->obmat, vertco);

			sub_v3_v3(vertco, birth.co);

			/* apply rotation, size & location */
			sub_qt_qtqt(rot, state.rot, birth.rot);
			mul_qt_v3(rot, vertco);

			if (emd->flag & eExplodeFlag_PaSize)
				mul_v3_fl(vertco, pa->size);

			add_v3_v3(vertco, state.co);

			mul_m4_v3(imat, vertco);
		}
	}
	BLI_edgehashIterator_free(ehi);

	/*map new vertices to faces*/
	for (i = 0, u = 0; i < totface; i++) {
		MFace source;
		int orig_v4;

		if (facepa[i] != totpart) {
			pa = pars + facepa[i];

			if (pa->alive == PARS_UNBORN && (emd->flag & eExplodeFlag_Unborn) == 0) continue;
			if (pa->alive == PARS_ALIVE && (emd->flag & eExplodeFlag_Alive) == 0) continue;
			if (pa->alive == PARS_DEAD && (emd->flag & eExplodeFlag_Dead) == 0) continue;
		}

		dm->getTessFace(dm, i, &source);
		mf = CDDM_get_tessface(explode, u);
		
		orig_v4 = source.v4;

		if (facepa[i] != totpart && cfra < pa->time)
			mindex = totvert + totpart;
		else 
			mindex = totvert + facepa[i];

		source.v1 = edgecut_get(vertpahash, source.v1, mindex);
		source.v2 = edgecut_get(vertpahash, source.v2, mindex);
		source.v3 = edgecut_get(vertpahash, source.v3, mindex);
		if (source.v4)
			source.v4 = edgecut_get(vertpahash, source.v4, mindex);

		DM_copy_tessface_data(dm, explode, i, u, 1);

		*mf = source;

		/* override uv channel for particle age */
		if (mtface) {
			float age = (cfra - pa->time) / pa->lifetime;
			/* Clamp to this range to avoid flipping to the other side of the coordinates. */
			CLAMP(age, 0.001f, 0.999f);

			mtf = mtface + u;

			mtf->uv[0][0] = mtf->uv[1][0] = mtf->uv[2][0] = mtf->uv[3][0] = age;
			mtf->uv[0][1] = mtf->uv[1][1] = mtf->uv[2][1] = mtf->uv[3][1] = 0.5f;
		}

		test_index_face(mf, &explode->faceData, u, (orig_v4 ? 4 : 3));
		u++;
	}

	/* cleanup */
	BLI_edgehash_free(vertpahash, NULL);

	/* finalization */
	CDDM_calc_edges_tessface(explode);
	CDDM_tessfaces_to_faces(explode);
	explode->dirty |= DM_DIRTY_NORMALS;

	if (psmd->psys->lattice_deform_data) {
		end_latt_deform(psmd->psys->lattice_deform_data);
		psmd->psys->lattice_deform_data = NULL;
	}

	return explode;
}

static ParticleSystemModifierData *findPrecedingParticlesystem(Object *ob, ModifierData *emd)
{
	ModifierData *md;
	ParticleSystemModifierData *psmd = NULL;

	for (md = ob->modifiers.first; emd != md; md = md->next) {
		if (md->type == eModifierType_ParticleSystem)
			psmd = (ParticleSystemModifierData *) md;
	}
	return psmd;
}
static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
                                  DerivedMesh *derivedData,
                                  ModifierApplyFlag UNUSED(flag))
{
	DerivedMesh *dm = derivedData;
	ExplodeModifierData *emd = (ExplodeModifierData *) md;
	ParticleSystemModifierData *psmd = findPrecedingParticlesystem(ob, md);

	if (psmd) {
		ParticleSystem *psys = psmd->psys;

		if (psys == NULL || psys->totpart == 0) return derivedData;
		if (psys->part == NULL || psys->particles == NULL) return derivedData;
		if (psmd->dm_final == NULL) return derivedData;

		DM_ensure_tessface(dm); /* BMESH - UNTIL MODIFIER IS UPDATED FOR MPoly */

		/* 1. find faces to be exploded if needed */
		if (emd->facepa == NULL ||
		    psmd->flag & eParticleSystemFlag_Pars ||
		    emd->flag & eExplodeFlag_CalcFaces ||
		    MEM_allocN_len(emd->facepa) / sizeof(int) != dm->getNumTessFaces(dm))
		{
			if (psmd->flag & eParticleSystemFlag_Pars)
				psmd->flag &= ~eParticleSystemFlag_Pars;
			
			if (emd->flag & eExplodeFlag_CalcFaces)
				emd->flag &= ~eExplodeFlag_CalcFaces;

			createFacepa(emd, psmd, derivedData);
		}
		/* 2. create new mesh */
		if (emd->flag & eExplodeFlag_EdgeCut) {
			int *facepa = emd->facepa;
			DerivedMesh *splitdm = cutEdges(emd, dm);
			DerivedMesh *explode = explodeMesh(emd, psmd, md->scene, ob, splitdm);

			MEM_freeN(emd->facepa);
			emd->facepa = facepa;
			splitdm->release(splitdm);
			return explode;
		}
		else
			return explodeMesh(emd, psmd, md->scene, ob, derivedData);
	}
	return derivedData;
}


ModifierTypeInfo modifierType_Explode = {
	/* name */              "Explode",
	/* structName */        "ExplodeModifierData",
	/* structSize */        sizeof(ExplodeModifierData),
	/* type */              eModifierTypeType_Constructive,
	/* flags */             eModifierTypeFlag_AcceptsMesh,
	/* copyData */          copyData,
	/* deformVerts */       NULL,
	/* deformMatrices */    NULL,
	/* deformVertsEM */     NULL,
	/* deformMatricesEM */  NULL,
	/* applyModifier */     applyModifier,
	/* applyModifierEM */   NULL,
	/* initData */          initData,
	/* requiredDataMask */  requiredDataMask,
	/* freeData */          freeData,
	/* isDisabled */        NULL,
	/* updateDepgraph */    NULL,
	/* updateDepsgraph */   NULL,
	/* dependsOnTime */     dependsOnTime,
	/* dependsOnNormals */  NULL,
	/* foreachObjectLink */ NULL,
	/* foreachIDLink */     NULL,
	/* foreachTexLink */    NULL,
};
