Fix T47038: Particles in Particle Edit Mode get added in completely wrong location.

It also fixes another issue (crash) related to symmetric editing.

Quite involved, we (try to!) fix complete broken logic of parts of particle code, which would use poly index
as tessface one (or vice-versa). Issue most probably goes back to BMesh integration time...

This patch mostly fixes particle editing mode:
  - Adding/removing particles when using generative modifiers (like subsurf) should now work.
  - Adding/removing particles with a non-tessellated mesh (i.e. one having ngons) should also mostly work.
  - X-axis-mirror-editing particles over ngons does not really work, not sure why currently.
  - All this in both 'modes' (with or without using modifier stack for particles).

Tech side:
  - Store a deformed-only DM in particle modifier data.
  - Rename existing DM to make it clear it's a final one.
  - Use deformed-only DM's tessface2poly mapping to 'solve' poly/tessface mismatches.
  - Make (part of) mirror-editing code able to use a DM instead of raw mesh, so that we can mirror based on final DM
    when editing particles using modifier stack (mandatory, since there is no way currently to find orig tessface
    from an final DM tessface index).

Note that this patch is not really nice and clean (current particles are beyond hope on this side anyway),
it's more like some urgency bandage. Whole crap needs complete rewrite anyway,
BMesh's polygons make it really hard to work with current system (and looptri would not help much here).

Also, did not test everything possibly affected by those changes, so it needs some users' testing & validation too.

Reviewers: psy-fi

Subscribers: dfelinto, eyecandy

Maniphest Tasks: T47038

Differential Revision: https://developer.blender.org/D1685

5 files changed, 220 insertions, 122 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index e26e5148ff6..9fc438319cb 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -43,6 +43,7 @@
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
 
+#include "BLI_array.h"
 #include "BLI_blenlib.h"
 #include "BLI_bitmap.h"
 #include "BLI_math.h"
@@ -3668,26 +3669,73 @@ static DerivedMesh *navmesh_dm_createNavMeshForVisualization(DerivedMesh *dm)
 
 void DM_init_origspace(DerivedMesh *dm)
 {
-	static float default_osf[4][2] = {{0, 0}, {1, 0}, {1, 1}, {0, 1}};
+	const float default_osf[4][2] = {{0, 0}, {1, 0}, {1, 1}, {0, 1}};
 
 	OrigSpaceLoop *lof_array = CustomData_get_layer(&dm->loopData, CD_ORIGSPACE_MLOOP);
-	OrigSpaceLoop *lof;
 	const int numpoly = dm->getNumPolys(dm);
 	// const int numloop = dm->getNumLoops(dm);
+	MVert *mv = dm->getVertArray(dm);
+	MLoop *ml = dm->getLoopArray(dm);
 	MPoly *mp = dm->getPolyArray(dm);
-	int i, j;
+	int i, j, k;
+
+	float (*vcos_2d)[2] = NULL;
+	BLI_array_staticdeclare(vcos_2d, 64);
 
 	for (i = 0; i < numpoly; i++, mp++) {
-		/* only quads/tri's for now */
+		OrigSpaceLoop *lof = lof_array + mp->loopstart;
+
 		if (mp->totloop == 3 || mp->totloop == 4) {
-			lof = lof_array + mp->loopstart;
 			for (j = 0; j < mp->totloop; j++, lof++) {
 				copy_v2_v2(lof->uv, default_osf[j]);
 			}
 		}
+		else {
+			MLoop *l = &ml[mp->loopstart];
+			float p_nor[3], co[3];
+			float mat[3][3];
+
+			float min[2] = {FLT_MAX, FLT_MAX}, max[2] = {FLT_MIN, FLT_MIN};
+			float translate[2], scale[2];
+
+			BKE_mesh_calc_poly_normal(mp, l, mv, p_nor);
+			axis_dominant_v3_to_m3(mat, p_nor);
+
+			BLI_array_empty(vcos_2d);
+			BLI_array_reserve(vcos_2d, mp->totloop);
+			for (j = 0; j < mp->totloop; j++, l++) {
+				mul_v3_m3v3(co, mat, mv[l->v].co);
+				copy_v2_v2(vcos_2d[j], co);
+
+				for (k = 0; k < 2; k++) {
+					if (co[k] > max[k])
+						max[k] = co[k];
+					else if (co[k] < min[k])
+						min[k] = co[k];
+				}
+			}
+
+			/* Brings min to (0, 0). */
+			negate_v2_v2(translate, min);
+
+			/* Scale will bring max to (1, 1). */
+			sub_v2_v2v2(scale, max, min);
+			if (scale[0] == 0.0f)
+				scale[0] = 1e-9f;
+			if (scale[1] == 0.0f)
+				scale[1] = 1e-9f;
+			invert_v2(scale);
+
+			/* Finally, transform all vcos_2d into ((0, 0), (1, 1)) square and assing them as origspace. */
+			for (j = 0; j < mp->totloop; j++, lof++) {
+				add_v2_v2v2(lof->uv, vcos_2d[j], translate);
+				mul_v2_v2(lof->uv, scale);
+			}
+		}
 	}
 
 	dm->dirty |= DM_DIRTY_TESS_CDLAYERS;
+	BLI_array_free(vcos_2d);
 }
 
 
diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index 89f22b8e742..b448bec84e3 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -364,10 +364,15 @@ void BKE_object_free_caches(Object *object)
 	for (md = object->modifiers.first; md != NULL; md = md->next) {
 		if (md->type == eModifierType_ParticleSystem) {
 			ParticleSystemModifierData *psmd = (ParticleSystemModifierData *) md;
-			if (psmd->dm != NULL) {
-				psmd->dm->needsFree = 1;
-				psmd->dm->release(psmd->dm);
-				psmd->dm = NULL;
+			if (psmd->dm_final != NULL) {
+				psmd->dm_final->needsFree = 1;
+				psmd->dm_final->release(psmd->dm_final);
+				psmd->dm_final = NULL;
+				if (psmd->dm_deformed != NULL) {
+					psmd->dm_deformed->needsFree = 1;
+					psmd->dm_deformed->release(psmd->dm_deformed);
+					psmd->dm_deformed = NULL;
+				}
 				psmd->flag |= eParticleSystemFlag_file_loaded;
 				update_flag |= OB_RECALC_DATA;
 			}
diff --git a/source/blender/blenkernel/intern/particle.c b/source/blender/blenkernel/intern/particle.c
index b3be5676607..39f0e7cbb84 100644
--- a/source/blender/blenkernel/intern/particle.c
+++ b/source/blender/blenkernel/intern/particle.c
@@ -623,8 +623,8 @@ void psys_render_set(Object *ob, ParticleSystem *psys, float viewmat[4][4], floa
 	data->childcachebufs.last = psys->childcachebufs.last;
 	data->totchildcache = psys->totchildcache;
 
-	if (psmd->dm)
-		data->dm = CDDM_copy(psmd->dm);
+	if (psmd->dm_final)
+		data->dm = CDDM_copy(psmd->dm_final);
 	data->totdmvert = psmd->totdmvert;
 	data->totdmedge = psmd->totdmedge;
 	data->totdmface = psmd->totdmface;
@@ -651,7 +651,7 @@ void psys_render_set(Object *ob, ParticleSystem *psys, float viewmat[4][4], floa
 		psys->recalc |= PSYS_RECALC_RESET;
 }
 
-void psys_render_restore(Object *ob, ParticleSystem *psys)
+void psys_render_restore(Scene *scene, Object *ob, ParticleSystem *psys)
 {
 	ParticleRenderData *data;
 	ParticleSystemModifierData *psmd = psys_get_modifier(ob, psys);
@@ -665,9 +665,14 @@ void psys_render_restore(Object *ob, ParticleSystem *psys)
 	if (data->elems)
 		MEM_freeN(data->elems);
 
-	if (psmd->dm) {
-		psmd->dm->needsFree = 1;
-		psmd->dm->release(psmd->dm);
+	if (psmd->dm_final) {
+		psmd->dm_final->needsFree = 1;
+		psmd->dm_final->release(psmd->dm_final);
+	}
+	if (psmd->dm_deformed) {
+		psmd->dm_deformed->needsFree = 1;
+		psmd->dm_deformed->release(psmd->dm_deformed);
+		psmd->dm_deformed = NULL;
 	}
 
 	psys_free_path_cache(psys, NULL);
@@ -689,14 +694,19 @@ void psys_render_restore(Object *ob, ParticleSystem *psys)
 	psys->childcachebufs.last = data->childcachebufs.last;
 	psys->totchildcache = data->totchildcache;
 
-	psmd->dm = data->dm;
+	psmd->dm_final = data->dm;
 	psmd->totdmvert = data->totdmvert;
 	psmd->totdmedge = data->totdmedge;
 	psmd->totdmface = data->totdmface;
 	psmd->flag &= ~eParticleSystemFlag_psys_updated;
 
-	if (psmd->dm)
-		psys_calc_dmcache(ob, psmd->dm, psys);
+	if (psmd->dm_final) {
+		if (!psmd->dm_final->deformedOnly) {
+			psmd->dm_deformed = CDDM_copy(mesh_get_derived_deform(scene, ob, CD_MASK_BAREMESH | CD_MASK_MFACE));
+			DM_ensure_tessface(psmd->dm_deformed);
+		}
+		psys_calc_dmcache(ob, psmd->dm_final, psmd->dm_deformed, psys);
+	}
 
 	MEM_freeN(data);
 	psys->renderdata = NULL;
@@ -1383,78 +1393,114 @@ static void psys_origspace_to_w(OrigSpaceFace *osface, int quad, const float w[4
 	}
 }
 
-/* find the derived mesh face for a particle, set the mf passed. this is slow
- * and can be optimized but only for many lookups. returns the face index. */
-int psys_particle_dm_face_lookup(Object *ob, DerivedMesh *dm, int index, const float fw[4], struct LinkNode *node)
+/**
+ * Find the final derived mesh tessface for a particle, from its original tessface index.
+ * This is slow and can be optimized but only for many lookups.
+ *
+ * \param dm_final final DM, it may not have the same topology as original mesh.
+ * \param dm_deformed deformed-only DM, it has the exact same topology as original mesh.
+ * \param findex_orig the input tessface index.
+ * \param fw face weights (position of the particle inside the \a findex_orig tessface).
+ * \param poly_nodes may be NULL, otherwise an array of linked list, one for each final DM polygon, containing all
+ *                   its tessfaces indices.
+ * \return the DM tessface index.
+ */
+int psys_particle_dm_face_lookup(
+        DerivedMesh *dm_final, DerivedMesh *dm_deformed,
+        int findex_orig, const float fw[4], struct LinkNode **poly_nodes)
 {
-	Mesh *me = (Mesh *)ob->data;
-	MPoly *mpoly;
-	OrigSpaceFace *osface;
-	int quad, findex, totface;
+	MFace *mtessface_final;
+	OrigSpaceFace *osface_final;
+	int totface_final;
+	int pindex_orig;
 	float uv[2], (*faceuv)[2];
 
-	/* double lookup */
-	const int *index_mf_to_mpoly = dm->getTessFaceDataArray(dm, CD_ORIGINDEX);
-	const int *index_mp_to_orig  = dm->getPolyDataArray(dm, CD_ORIGINDEX);
-	if (index_mf_to_mpoly == NULL) {
-		index_mp_to_orig = NULL;
+	const int *index_mf_to_mpoly_deformed = NULL;
+	const int *index_mf_to_mpoly = NULL;
+	const int *index_mp_to_orig = NULL;
+
+	index_mf_to_mpoly = dm_final->getTessFaceDataArray(dm_final, CD_ORIGINDEX);
+	index_mp_to_orig = dm_final->getPolyDataArray(dm_final, CD_ORIGINDEX);
+	BLI_assert(index_mf_to_mpoly);
+
+	if (dm_deformed) {
+		index_mf_to_mpoly_deformed = dm_deformed->getTessFaceDataArray(dm_deformed, CD_ORIGINDEX);
+	}
+	else {
+		BLI_assert(dm_final->deformedOnly);
+		index_mf_to_mpoly_deformed = index_mf_to_mpoly;
+	}
+	BLI_assert(index_mf_to_mpoly_deformed);
+
+	pindex_orig = index_mf_to_mpoly_deformed[findex_orig];
+
+	if (dm_deformed == NULL) {
+		dm_deformed = dm_final;
 	}
 
-	totface = dm->getNumTessFaces(dm);
-	if (!totface) {
+	index_mf_to_mpoly_deformed = NULL;
+
+	totface_final = dm_final->getNumTessFaces(dm_final);
+	if (!totface_final) {
 		return DMCACHE_NOTFOUND;
 	}
 
-	mpoly = dm->getPolyArray(dm);
-	osface = dm->getTessFaceDataArray(dm, CD_ORIGSPACE);
+	mtessface_final = dm_final->getTessFaceArray(dm_final);
+	osface_final = dm_final->getTessFaceDataArray(dm_final, CD_ORIGSPACE);
 
-	if (osface == NULL || index_mf_to_mpoly == NULL) {
-		/* Assume we don't need osface data */
-		if (index < totface) {
+	if (osface_final == NULL) {
+		/* Assume we don't need osface_final data, and we get a direct 1-1 mapping... */
+		if (findex_orig < totface_final) {
 			//printf("\tNO CD_ORIGSPACE, assuming not needed\n");
-			return index;
+			return findex_orig;
 		}
 		else {
 			printf("\tNO CD_ORIGSPACE, error out of range\n");
 			return DMCACHE_NOTFOUND;
 		}
 	}
-	else if (index >= me->totpoly)
+	else if (findex_orig >= dm_deformed->getNumTessFaces(dm_deformed)) {
 		return DMCACHE_NOTFOUND;  /* index not in the original mesh */
+	}
 
 	psys_w_to_origspace(fw, uv);
 	
-	if (node) { /* we have a linked list of faces that we use, faster! */
-		for (; node; node = node->next) {
-			findex = GET_INT_FROM_POINTER(node->link);
-			faceuv = osface[findex].uv;
-			quad = (mpoly[findex].totloop == 4);
+	if (poly_nodes) {
+		/* we can have a restricted linked list of faces to check, faster! */
+		LinkNode *tessface_node = poly_nodes[pindex_orig];
+
+		for (; tessface_node; tessface_node = tessface_node->next) {
+			int findex_dst = GET_INT_FROM_POINTER(tessface_node->link);
+			faceuv = osface_final[findex_dst].uv;
 
 			/* check that this intersects - Its possible this misses :/ -
 			 * could also check its not between */
-			if (quad) {
-				if (isect_point_quad_v2(uv, faceuv[0], faceuv[1], faceuv[2], faceuv[3]))
-					return findex;
+			if (mtessface_final[findex_dst].v4) {
+				if (isect_point_quad_v2(uv, faceuv[0], faceuv[1], faceuv[2], faceuv[3])) {
+					return findex_dst;
+				}
+			}
+			else if (isect_point_tri_v2(uv, faceuv[0], faceuv[1], faceuv[2])) {
+				return findex_dst;
 			}
-			else if (isect_point_tri_v2(uv, faceuv[0], faceuv[1], faceuv[2]))
-				return findex;
 		}
 	}
 	else { /* if we have no node, try every face */
-		for (findex = 0; findex < totface; findex++) {
-			const int findex_orig = DM_origindex_mface_mpoly(index_mf_to_mpoly, index_mp_to_orig, findex);
-			if (findex_orig == index) {
-				faceuv = osface[findex].uv;
-				quad = (mpoly[findex].totloop == 4);
+		for (int findex_dst = 0; findex_dst < totface_final; findex_dst++) {
+			/* If current tessface from 'final' DM and orig tessface (given by index) map to the same orig poly... */
+			if (DM_origindex_mface_mpoly(index_mf_to_mpoly, index_mp_to_orig, findex_dst) == pindex_orig) {
+				faceuv = osface_final[findex_dst].uv;
 
 				/* check that this intersects - Its possible this misses :/ -
 				 * could also check its not between */
-				if (quad) {
-					if (isect_point_quad_v2(uv, faceuv[0], faceuv[1], faceuv[2], faceuv[3]))
-						return findex;
+				if (mtessface_final[findex_dst].v4) {
+					if (isect_point_quad_v2(uv, faceuv[0], faceuv[1], faceuv[2], faceuv[3])) {
+						return findex_dst;
+					}
+				}
+				else if (isect_point_tri_v2(uv, faceuv[0], faceuv[1], faceuv[2])) {
+					return findex_dst;
 				}
-				else if (isect_point_tri_v2(uv, faceuv[0], faceuv[1], faceuv[2]))
-					return findex;
 			}
 		}
 	}
@@ -1523,7 +1569,7 @@ static int psys_map_index_on_dm(DerivedMesh *dm, int from, int index, int index_
 }
 
 /* interprets particle data to get a point on a mesh in object space */
-void psys_particle_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache,
+void psys_particle_on_dm(DerivedMesh *dm_final, int from, int index, int index_dmcache,
                          const float fw[4], float foffset, float vec[3], float nor[3], float utan[3], float vtan[3],
                          float orco[3], float ornor[3])
 {
@@ -1531,7 +1577,7 @@ void psys_particle_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache
 	float (*orcodata)[3];
 	int mapindex;
 
-	if (!psys_map_index_on_dm(dm, from, index, index_dmcache, fw, foffset, &mapindex, mapfw)) {
+	if (!psys_map_index_on_dm(dm_final, from, index, index_dmcache, fw, foffset, &mapindex, mapfw)) {
 		if (vec) { vec[0] = vec[1] = vec[2] = 0.0; }
 		if (nor) { nor[0] = nor[1] = 0.0; nor[2] = 1.0; }
 		if (orco) { orco[0] = orco[1] = orco[2] = 0.0; }
@@ -1542,13 +1588,13 @@ void psys_particle_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache
 		return;
 	}
 
-	orcodata = dm->getVertDataArray(dm, CD_ORCO);
+	orcodata = dm_final->getVertDataArray(dm_final, CD_ORCO);
 
 	if (from == PART_FROM_VERT) {
-		dm->getVertCo(dm, mapindex, vec);
+		dm_final->getVertCo(dm_final, mapindex, vec);
 
 		if (nor) {
-			dm->getVertNo(dm, mapindex, nor);
+			dm_final->getVertNo(dm_final, mapindex, nor);
 			normalize_v3(nor);
 		}
 
@@ -1556,7 +1602,7 @@ void psys_particle_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache
 			copy_v3_v3(orco, orcodata[mapindex]);
 
 		if (ornor) {
-			dm->getVertNo(dm, mapindex, ornor);
+			dm_final->getVertNo(dm_final, mapindex, ornor);
 			normalize_v3(ornor);
 		}
 
@@ -1570,9 +1616,9 @@ void psys_particle_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache
 		MTFace *mtface;
 		MVert *mvert;
 
-		mface = dm->getTessFaceData(dm, mapindex, CD_MFACE);
-		mvert = dm->getVertDataArray(dm, CD_MVERT);
-		mtface = CustomData_get_layer(&dm->faceData, CD_MTFACE);
+		mface = dm_final->getTessFaceData(dm_final, mapindex, CD_MFACE);
+		mvert = dm_final->getVertDataArray(dm_final, CD_MVERT);
+		mtface = CustomData_get_layer(&dm_final->faceData, CD_MTFACE);
 
 		if (mtface)
 			mtface += mapindex;
@@ -1689,7 +1735,7 @@ void psys_particle_on_emitter(ParticleSystemModifierData *psmd, int from, int in
                               float fuv[4], float foffset, float vec[3], float nor[3], float utan[3], float vtan[3],
                               float orco[3], float ornor[3])
 {
-	if (psmd && psmd->dm) {
+	if (psmd && psmd->dm_final) {
 		if (psmd->psys->part->distr == PART_DISTR_GRID && psmd->psys->part->from != PART_FROM_VERT) {
 			if (vec)
 				copy_v3_v3(vec, fuv);
@@ -1699,7 +1745,7 @@ void psys_particle_on_emitter(ParticleSystemModifierData *psmd, int from, int in
 			return;
 		}
 		/* we cant use the num_dmcache */
-		psys_particle_on_dm(psmd->dm, from, index, index_dmcache, fuv, foffset, vec, nor, utan, vtan, orco, ornor);
+		psys_particle_on_dm(psmd->dm_final, from, index, index_dmcache, fuv, foffset, vec, nor, utan, vtan, orco, ornor);
 	}
 	else
 		psys_particle_on_shape(from, index, fuv, vec, nor, utan, vtan, orco, ornor);
@@ -1971,7 +2017,7 @@ void psys_find_parents(ParticleSimulationData *sim)
 		psys_particle_on_emitter(sim->psmd, from, cpa->num, DMCACHE_ISCHILD, cpa->fuv, cpa->foffset, co, 0, 0, 0, orco, 0);
 
 		/* Check if particle doesn't exist because of texture influence. Insert only existing particles into kdtree. */
-		get_cpa_texture(sim->psmd->dm, psys, part, psys->particles + cpa->pa[0], p, cpa->num, cpa->fuv, orco, &ptex, PAMAP_DENS | PAMAP_CHILD, psys->cfra);
+		get_cpa_texture(sim->psmd->dm_final, psys, part, psys->particles + cpa->pa[0], p, cpa->num, cpa->fuv, orco, &ptex, PAMAP_DENS | PAMAP_CHILD, psys->cfra);
 
 		if (ptex.exist >= psys_frand(psys, p + 24)) {
 			BLI_kdtree_insert(tree, p, orco);
@@ -2183,7 +2229,7 @@ static void psys_thread_create_path(ParticleTask *task, struct ChildParticle *cp
 		for (w = 0; w < 4; w++)
 			sub_v3_v3v3(off1[w], co, key[w]->co);
 
-		psys_mat_hair_to_global(ob, ctx->sim.psmd->dm, psys->part->from, pa, hairmat);
+		psys_mat_hair_to_global(ob, ctx->sim.psmd->dm_final, psys->part->from, pa, hairmat);
 	}
 	else {
 		ParticleData *pa = psys->particles + cpa->parent;
@@ -2202,13 +2248,13 @@ static void psys_thread_create_path(ParticleTask *task, struct ChildParticle *cp
 		cpa_from = part->from;
 		cpa_num = pa->num;
 		/* XXX hack to avoid messed up particle num and subsequent crash (#40733) */
-		if (cpa_num > ctx->sim.psmd->dm->getNumTessFaces(ctx->sim.psmd->dm))
+		if (cpa_num > ctx->sim.psmd->dm_final->getNumTessFaces(ctx->sim.psmd->dm_final))
 			cpa_num = 0;
 		cpa_fuv = pa->fuv;
 
 		psys_particle_on_emitter(ctx->sim.psmd, cpa_from, cpa_num, DMCACHE_ISCHILD, cpa_fuv, pa->foffset, co, ornor, 0, 0, orco, 0);
 
-		psys_mat_hair_to_global(ob, ctx->sim.psmd->dm, psys->part->from, pa, hairmat);
+		psys_mat_hair_to_global(ob, ctx->sim.psmd->dm_final, psys->part->from, pa, hairmat);
 	}
 
 	child_keys->segments = ctx->segments;
@@ -2501,15 +2547,15 @@ void psys_cache_paths(ParticleSimulationData *sim, float cfra)
 
 	if ((psys->flag & PSYS_GLOBAL_HAIR) == 0) {
 		if ((psys->part->flag & PART_CHILD_EFFECT) == 0)
-			vg_effector = psys_cache_vgroup(psmd->dm, psys, PSYS_VG_EFFECTOR);
+			vg_effector = psys_cache_vgroup(psmd->dm_final, psys, PSYS_VG_EFFECTOR);
 		
 		if (!psys->totchild)
-			vg_length = psys_cache_vgroup(psmd->dm, psys, PSYS_VG_LENGTH);
+			vg_length = psys_cache_vgroup(psmd->dm_final, psys, PSYS_VG_LENGTH);
 	}
 
 	/* ensure we have tessfaces to be used for mapping */
 	if (part->from != PART_FROM_VERT) {
-		DM_ensure_tessface(psmd->dm);
+		DM_ensure_tessface(psmd->dm_final);
 	}
 
 	/*---first main loop: create all actual particles' paths---*/
@@ -2518,7 +2564,7 @@ void psys_cache_paths(ParticleSimulationData *sim, float cfra)
 			psys_get_texture(sim, pa, &ptex, PAMAP_LENGTH, 0.f);
 			pa_length = ptex.length * (1.0f - part->randlength * psys_frand(psys, psys->seed + p));
 			if (vg_length)
-				pa_length *= psys_particle_value_from_verts(psmd->dm, part->from, pa, vg_length);
+				pa_length *= psys_particle_value_from_verts(psmd->dm_final, part->from, pa, vg_length);
 		}
 
 		pind.keyed = keyed;
@@ -2535,7 +2581,7 @@ void psys_cache_paths(ParticleSimulationData *sim, float cfra)
 		init_particle_interpolation(sim->ob, sim->psys, pa, &pind);
 
 		/* hairmat is needed for for non-hair particle too so we get proper rotations */
-		psys_mat_hair_to_global(sim->ob, psmd->dm, psys->part->from, pa, hairmat);
+		psys_mat_hair_to_global(sim->ob, psmd->dm_final, psys->part->from, pa, hairmat);
 		copy_v3_v3(rotmat[0], hairmat[2]);
 		copy_v3_v3(rotmat[1], hairmat[1]);
 		copy_v3_v3(rotmat[2], hairmat[0]);
@@ -2590,7 +2636,7 @@ void psys_cache_paths(ParticleSimulationData *sim, float cfra)
 			if ((psys->part->flag & PART_CHILD_EFFECT) == 0) {
 				float effector = 1.0f;
 				if (vg_effector)
-					effector *= psys_particle_value_from_verts(psmd->dm, psys->part->from, pa, vg_effector);
+					effector *= psys_particle_value_from_verts(psmd->dm_final, psys->part->from, pa, vg_effector);
 
 				sub_v3_v3v3(vec, (cache[p] + 1)->co, cache[p]->co);
 				length = len_v3(vec);
@@ -2735,7 +2781,7 @@ void psys_cache_edit_paths(Scene *scene, Object *ob, PTCacheEdit *edit, float cf
 		init_particle_interpolation(ob, psys, pa, &pind);
 
 		if (psys) {
-			psys_mat_hair_to_global(ob, psmd->dm, psys->part->from, pa, hairmat);
+			psys_mat_hair_to_global(ob, psmd->dm_final, psys->part->from, pa, hairmat);
 			copy_v3_v3(rotmat[0], hairmat[2]);
 			copy_v3_v3(rotmat[1], hairmat[1]);
 			copy_v3_v3(rotmat[2], hairmat[0]);
@@ -3491,7 +3537,7 @@ void psys_get_texture(ParticleSimulationData *sim, ParticleData *pa, ParticleTex
 						mul_m4_v3(mtex->object->imat, texvec);
 					break;
 				case TEXCO_UV:
-					if (get_particle_uv(sim->psmd->dm, pa, 0, pa->fuv, mtex->uvname, texvec))
+					if (get_particle_uv(sim->psmd->dm_final, pa, 0, pa->fuv, mtex->uvname, texvec))
 						break;
 				/* no break, failed to get uv's, so let's try orco's */
 				case TEXCO_ORCO:
@@ -3691,7 +3737,7 @@ void psys_get_particle_on_path(ParticleSimulationData *sim, int p, ParticleKey *
 			}
 			else if (!keyed && !cached && !(psys->flag & PSYS_GLOBAL_HAIR)) {
 				if ((pa->flag & PARS_REKEY) == 0) {
-					psys_mat_hair_to_global(sim->ob, sim->psmd->dm, part->from, pa, hairmat);
+					psys_mat_hair_to_global(sim->ob, sim->psmd->dm_final, part->from, pa, hairmat);
 					mul_m4_v3(hairmat, state->co);
 					mul_mat3_m4_v3(hairmat, state->vel);
 
@@ -3758,7 +3804,7 @@ void psys_get_particle_on_path(ParticleSimulationData *sim, int p, ParticleKey *
 
 				psys_particle_on_emitter(psmd, part->from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, par_co, 0, 0, 0, par_orco, 0);
 				if (part->type == PART_HAIR)
-					psys_mat_hair_to_global(sim->ob, sim->psmd->dm, psys->part->from, pa, hairmat);
+					psys_mat_hair_to_global(sim->ob, sim->psmd->dm_final, psys->part->from, pa, hairmat);
 				else
 					unit_m4(hairmat);
 
@@ -3779,7 +3825,7 @@ void psys_get_particle_on_path(ParticleSimulationData *sim, int p, ParticleKey *
 				psys_particle_on_emitter(psmd, part->from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, par_co, 0, 0, 0, par_orco, 0);
 				if (part->type == PART_HAIR) {
 					psys_particle_on_emitter(psmd, cpa_from, cpa_num, DMCACHE_ISCHILD, cpa_fuv, pa->foffset, co, 0, 0, 0, orco, 0);
-					psys_mat_hair_to_global(sim->ob, sim->psmd->dm, psys->part->from, pa, hairmat);
+					psys_mat_hair_to_global(sim->ob, sim->psmd->dm_final, psys->part->from, pa, hairmat);
 				}
 				else {
 					copy_v3_v3(orco, cpa->fuv);
@@ -3798,7 +3844,7 @@ void psys_get_particle_on_path(ParticleSimulationData *sim, int p, ParticleKey *
 			/* get different child parameters from textures & vgroups */
 			memset(&ctx, 0, sizeof(ParticleThreadContext));
 			ctx.sim = *sim;
-			ctx.dm = psmd->dm;
+			ctx.dm = psmd->dm_final;
 			ctx.ma = ma;
 			/* TODO: assign vertex groups */
 			get_child_modifier_parameters(part, &ctx, cpa, cpa_from, cpa_num, cpa_fuv, orco, &ptex);
@@ -4026,10 +4072,10 @@ void psys_get_dupli_texture(ParticleSystem *psys, ParticleSettings *part,
 	uv[0] = uv[1] = 0.f;
 
 	if (cpa) {
-		if ((part->childtype == PART_CHILD_FACES) && (psmd->dm != NULL)) {
-			mtface = CustomData_get_layer(&psmd->dm->faceData, CD_MTFACE);
+		if ((part->childtype == PART_CHILD_FACES) && (psmd->dm_final != NULL)) {
+			mtface = CustomData_get_layer(&psmd->dm_final->faceData, CD_MTFACE);
 			if (mtface) {
-				mface = psmd->dm->getTessFaceData(psmd->dm, cpa->num, CD_MFACE);
+				mface = psmd->dm_final->getTessFaceData(psmd->dm_final, cpa->num, CD_MFACE);
 				mtface += cpa->num;
 				psys_interpolate_uvs(mtface, mface->v4, cpa->fuv, uv);
 			}
@@ -4042,21 +4088,21 @@ void psys_get_dupli_texture(ParticleSystem *psys, ParticleSettings *part,
 		}
 	}
 
-	if ((part->from == PART_FROM_FACE) && (psmd->dm != NULL)) {
-		mtface = CustomData_get_layer(&psmd->dm->faceData, CD_MTFACE);
+	if ((part->from == PART_FROM_FACE) && (psmd->dm_final != NULL)) {
+		mtface = CustomData_get_layer(&psmd->dm_final->faceData, CD_MTFACE);
 		num = pa->num_dmcache;
 
 		if (num == DMCACHE_NOTFOUND)
 			num = pa->num;
 
-		if (num >= psmd->dm->getNumTessFaces(psmd->dm)) {
+		if (num >= psmd->dm_final->getNumTessFaces(psmd->dm_final)) {
 			/* happens when simplify is enabled
 			 * gives invalid coords but would crash otherwise */
 			num = DMCACHE_NOTFOUND;
 		}
 
 		if (mtface && !ELEM(num, DMCACHE_NOTFOUND, DMCACHE_ISCHILD)) {
-			mface = psmd->dm->getTessFaceData(psmd->dm, num, CD_MFACE);
+			mface = psmd->dm_final->getTessFaceData(psmd->dm_final, num, CD_MFACE);
 			mtface += num;
 			psys_interpolate_uvs(mtface, mface->v4, pa->fuv, uv);
 		}
@@ -4231,7 +4277,7 @@ void psys_apply_hair_lattice(Scene *scene, Object *ob, ParticleSystem *psys)
 		float hairmat[4][4], imat[4][4];
 
 		for (p = 0; p < psys->totpart; p++, pa++) {
-			psys_mat_hair_to_global(sim.ob, sim.psmd->dm, psys->part->from, pa, hairmat);
+			psys_mat_hair_to_global(sim.ob, sim.psmd->dm_final, psys->part->from, pa, hairmat);
 			invert_m4_m4(imat, hairmat);
 
 			hkey = pa->hair;
diff --git a/source/blender/blenkernel/intern/particle_distribute.c b/source/blender/blenkernel/intern/particle_distribute.c
index 9523ece5f73..9f60cbb88e3 100644
--- a/source/blender/blenkernel/intern/particle_distribute.c
+++ b/source/blender/blenkernel/intern/particle_distribute.c
@@ -79,7 +79,7 @@ static void alloc_child_particles(ParticleSystem *psys, int tot)
 	}
 }
 
-static void distribute_simple_children(Scene *scene, Object *ob, DerivedMesh *finaldm, ParticleSystem *psys)
+static void distribute_simple_children(Scene *scene, Object *ob, DerivedMesh *finaldm, DerivedMesh *deformdm, ParticleSystem *psys)
 {
 	ChildParticle *cpa = NULL;
 	int i, p;
@@ -106,7 +106,7 @@ static void distribute_simple_children(Scene *scene, Object *ob, DerivedMesh *fi
 		}
 	}
 	/* dmcache must be updated for parent particles if children from faces is used */
-	psys_calc_dmcache(ob, finaldm, psys);
+	psys_calc_dmcache(ob, finaldm, deformdm, psys);
 }
 static void distribute_grid(DerivedMesh *dm, ParticleSystem *psys)
 {
@@ -763,7 +763,7 @@ static void distribute_invalid(Scene *scene, ParticleSystem *psys, int from)
 static int psys_thread_context_init_distribute(ParticleThreadContext *ctx, ParticleSimulationData *sim, int from)
 {
 	Scene *scene = sim->scene;
-	DerivedMesh *finaldm = sim->psmd->dm;
+	DerivedMesh *finaldm = sim->psmd->dm_final;
 	Object *ob = sim->ob;
 	ParticleSystem *psys= sim->psys;
 	ParticleData *pa=0, *tpars= 0;
@@ -800,7 +800,7 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
 		/* Simple children */
 		if (part->childtype != PART_CHILD_FACES) {
 			BLI_srandom(31415926 + psys->seed + psys->child_seed);
-			distribute_simple_children(scene, ob, finaldm, psys);
+			distribute_simple_children(scene, ob, finaldm, sim->psmd->dm_deformed, psys);
 			return 0;
 		}
 	}
@@ -1110,7 +1110,7 @@ static void distribute_particles_on_dm(ParticleSimulationData *sim, int from)
 	TaskPool *task_pool;
 	ParticleThreadContext ctx;
 	ParticleTask *tasks;
-	DerivedMesh *finaldm = sim->psmd->dm;
+	DerivedMesh *finaldm = sim->psmd->dm_final;
 	int i, totpart, numtasks;
 	
 	/* create a task pool for distribution tasks */
@@ -1135,7 +1135,7 @@ static void distribute_particles_on_dm(ParticleSimulationData *sim, int from)
 	
 	BLI_task_pool_free(task_pool);
 	
-	psys_calc_dmcache(sim->ob, finaldm, sim->psys);
+	psys_calc_dmcache(sim->ob, finaldm, sim->psmd->dm_deformed, sim->psys);
 	
 	if (ctx.dm != finaldm)
 		ctx.dm->release(ctx.dm);
@@ -1159,7 +1159,7 @@ void distribute_particles(ParticleSimulationData *sim, int from)
 	int distr_error=0;
 
 	if (psmd) {
-		if (psmd->dm)
+		if (psmd->dm_final)
 			distribute_particles_on_dm(sim, from);
 		else
 			distr_error=1;
diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index 130b56987e2..bf506c8545b 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -311,7 +311,7 @@ int psys_get_tot_child(Scene *scene, ParticleSystem *psys)
 /*			Distribution						*/
 /************************************************/
 
-void psys_calc_dmcache(Object *ob, DerivedMesh *dm, ParticleSystem *psys)
+void psys_calc_dmcache(Object *ob, DerivedMesh *dm_final, DerivedMesh *dm_deformed, ParticleSystem *psys)
 {
 	/* use for building derived mesh mapping info:
 	 *
@@ -324,13 +324,13 @@ void psys_calc_dmcache(Object *ob, DerivedMesh *dm, ParticleSystem *psys)
 	PARTICLE_P;
 	
 	/* CACHE LOCATIONS */
-	if (!dm->deformedOnly) {
+	if (!dm_final->deformedOnly) {
 		/* Will use later to speed up subsurf/derivedmesh */
 		LinkNode *node, *nodedmelem, **nodearray;
 		int totdmelem, totelem, i, *origindex, *origindex_poly = NULL;
 
 		if (psys->part->from == PART_FROM_VERT) {
-			totdmelem= dm->getNumVerts(dm);
+			totdmelem= dm_final->getNumVerts(dm_final);
 
 			if (use_modifier_stack) {
 				totelem= totdmelem;
@@ -338,11 +338,11 @@ void psys_calc_dmcache(Object *ob, DerivedMesh *dm, ParticleSystem *psys)
 			}
 			else {
 				totelem= me->totvert;
-				origindex= dm->getVertDataArray(dm, CD_ORIGINDEX);
+				origindex= dm_final->getVertDataArray(dm_final, CD_ORIGINDEX);
 			}
 		}
 		else { /* FROM_FACE/FROM_VOLUME */
-			totdmelem= dm->getNumTessFaces(dm);
+			totdmelem= dm_final->getNumTessFaces(dm_final);
 
 			if (use_modifier_stack) {
 				totelem= totdmelem;
@@ -350,20 +350,20 @@ void psys_calc_dmcache(Object *ob, DerivedMesh *dm, ParticleSystem *psys)
 				origindex_poly= NULL;
 			}
 			else {
-				totelem= me->totpoly;
-				origindex= dm->getTessFaceDataArray(dm, CD_ORIGINDEX);
+				totelem = dm_deformed->getNumTessFaces(dm_deformed);
+				origindex = dm_final->getTessFaceDataArray(dm_final, CD_ORIGINDEX);
 
 				/* for face lookups we need the poly origindex too */
-				origindex_poly= dm->getPolyDataArray(dm, CD_ORIGINDEX);
+				origindex_poly= dm_final->getPolyDataArray(dm_final, CD_ORIGINDEX);
 				if (origindex_poly == NULL) {
 					origindex= NULL;
 				}
 			}
 		}
-	
+
 		nodedmelem= MEM_callocN(sizeof(LinkNode)*totdmelem, "psys node elems");
 		nodearray= MEM_callocN(sizeof(LinkNode *)*totelem, "psys node array");
-		
+
 		for (i=0, node=nodedmelem; i<totdmelem; i++, node++) {
 			int origindex_final;
 			node->link = SET_INT_IN_POINTER(i);
@@ -392,7 +392,7 @@ void psys_calc_dmcache(Object *ob, DerivedMesh *dm, ParticleSystem *psys)
 				}
 			}
 		}
-		
+
 		/* cache the verts/faces! */
 		LOOP_PARTICLES {
 			if (pa->num < 0) {
@@ -414,9 +414,7 @@ void psys_calc_dmcache(Object *ob, DerivedMesh *dm, ParticleSystem *psys)
 						pa->num_dmcache = DMCACHE_NOTFOUND;
 				}
 				else { /* FROM_FACE/FROM_VOLUME */
-					/* Note that sometimes the pa->num is over the nodearray size, this is bad, maybe there is a better place to fix this,
-					 * but for now passing NULL is OK. every face will be searched for the particle so its slower - Campbell */
-					pa->num_dmcache= psys_particle_dm_face_lookup(ob, dm, pa->num, pa->fuv, pa->num < totelem ? nodearray[pa->num] : NULL);
+					pa->num_dmcache = psys_particle_dm_face_lookup(dm_final, dm_deformed, pa->num, pa->fuv, nodearray);
 				}
 			}
 		}
@@ -429,8 +427,9 @@ void psys_calc_dmcache(Object *ob, DerivedMesh *dm, ParticleSystem *psys)
 		 * should know to use the num or num_dmcache, set the num_dmcache to
 		 * an invalid value, just in case */
 		
-		LOOP_PARTICLES
+		LOOP_PARTICLES {
 			pa->num_dmcache = DMCACHE_NOTFOUND;
+		}
 	}
 }
 
@@ -439,7 +438,7 @@ void psys_thread_context_init(ParticleThreadContext *ctx, ParticleSimulationData
 {
 	memset(ctx, 0, sizeof(ParticleThreadContext));
 	ctx->sim = *sim;
-	ctx->dm = ctx->sim.psmd->dm;
+	ctx->dm = ctx->sim.psmd->dm_final;
 	ctx->ma = give_current_material(sim->ob, sim->psys->part->omat);
 }
 
@@ -3054,7 +3053,7 @@ static void hair_create_input_dm(ParticleSimulationData *sim, int totpoint, int
 		pa->hair_index = hair_index;
 		use_hair = psys_hair_use_simulation(pa, max_length);
 		
-		psys_mat_hair_to_object(sim->ob, sim->psmd->dm, psys->part->from, pa, hairmat);
+		psys_mat_hair_to_object(sim->ob, sim->psmd->dm_final, psys->part->from, pa, hairmat);
 		mul_m4_m4m4(root_mat, sim->ob->obmat, hairmat);
 		normalize_m4(root_mat);
 		
@@ -3209,7 +3208,7 @@ static void hair_step(ParticleSimulationData *sim, float cfra)
 
 	if (psys->recalc & PSYS_RECALC_RESET) {
 		/* need this for changing subsurf levels */
-		psys_calc_dmcache(sim->ob, sim->psmd->dm, psys);
+		psys_calc_dmcache(sim->ob, sim->psmd->dm_final, sim->psmd->dm_deformed, psys);
 
 		if (psys->clmd)
 			cloth_free_modifier(psys->clmd);
@@ -3256,7 +3255,7 @@ static void save_hair(ParticleSimulationData *sim, float UNUSED(cfra))
 
 		if (pa->totkey) {
 			sub_v3_v3(key->co, root->co);
-			psys_vec_rot_to_face(sim->psmd->dm, pa, key->co);
+			psys_vec_rot_to_face(sim->psmd->dm_final, pa, key->co);
 		}
 
 		key->time = pa->state.time;
@@ -4064,11 +4063,11 @@ void particle_system_update(Scene *scene, Object *ob, ParticleSystem *psys)
 			return;
 	}
 
-	if (!sim.psmd->dm)
+	if (!sim.psmd->dm_final)
 		return;
 
 	if (part->from != PART_FROM_VERT) {
-		DM_ensure_tessface(sim.psmd->dm);
+		DM_ensure_tessface(sim.psmd->dm_final);
 	}
 
 	/* execute drivers only, as animation has already been done */