Modifier stack: move vgroup editing modifiers to new Mesh-based system.

Some notes here:
* Proximity with non-mesh objects (like curve, see TEST_2 scene in
weightvg testfile) are not working currently. This is known TODO of COW
depsgraph project.
* Proximity modifier is slower, due to some other TODO pending on
BVHTree creation/caching for Mesh.

5 files changed, 199 insertions, 138 deletions

diff --git a/source/blender/modifiers/intern/MOD_weightvg_util.c b/source/blender/modifiers/intern/MOD_weightvg_util.c
index 416f2964d6e..bb8ccb8899e 100644
--- a/source/blender/modifiers/intern/MOD_weightvg_util.c
+++ b/source/blender/modifiers/intern/MOD_weightvg_util.c
@@ -34,13 +34,14 @@
 #include "BLI_utildefines.h"
 
 #include "DNA_color_types.h"      /* CurveMapping. */
+#include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
 #include "DNA_modifier_types.h"
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
 
-#include "BKE_cdderivedmesh.h"
 #include "BKE_colortools.h"       /* CurveMapping. */
+#include "BKE_customdata.h"
 #include "BKE_deform.h"
 #include "BKE_modifier.h"
 #include "BKE_texture.h"          /* Texture masking. */
@@ -114,9 +115,9 @@ void weightvg_do_map(int num, float *new_w, short falloff_type, CurveMapping *cm
  * vertex index (in case the weight tables do not cover the whole vertices...).
  * XXX The standard "factor" value is assumed in [0.0, 1.0] range. Else, weird results might appear.
  */
-void weightvg_do_mask(int num, const int *indices, float *org_w, const float *new_w,
-                      Object *ob, DerivedMesh *dm, float fact, const char defgrp_name[MAX_VGROUP_NAME],
-                      Scene *scene, Tex *texture, int tex_use_channel, int tex_mapping,
+void weightvg_do_mask(const int num, const int *indices, float *org_w, const float *new_w,
+                      Object *ob, Mesh *mesh, const float fact, const char defgrp_name[MAX_VGROUP_NAME],
+                      Scene *scene, Tex *texture, const int tex_use_channel, const int tex_mapping,
                       Object *tex_map_object, const char *tex_uvlayer_name)
 {
 	int ref_didx;
@@ -131,8 +132,7 @@ void weightvg_do_mask(int num, const int *indices, float *org_w, const float *ne
 		float (*tex_co)[3];
 		/* See mapping note below... */
 		MappingInfoModifierData t_map;
-		float (*v_co)[3];
-		int numVerts = dm->getNumVerts(dm);
+		const int numVerts = mesh->totvert;
 
 		/* Use new generic get_texture_coords, but do not modify our DNA struct for it...
 		 * XXX Why use a ModifierData stuff here ? Why not a simple, generic struct for parameters ?
@@ -143,11 +143,9 @@ void weightvg_do_mask(int num, const int *indices, float *org_w, const float *ne
 		t_map.map_object = tex_map_object;
 		BLI_strncpy(t_map.uvlayer_name, tex_uvlayer_name, sizeof(t_map.uvlayer_name));
 		t_map.texmapping = tex_mapping;
-		v_co = MEM_malloc_arrayN(numVerts, sizeof(*v_co), "WeightVG Modifier, TEX mode, v_co");
-		dm->getVertCos(dm, v_co);
+
 		tex_co = MEM_calloc_arrayN(numVerts, sizeof(*tex_co), "WeightVG Modifier, TEX mode, tex_co");
-		get_texture_coords(&t_map, ob, dm, v_co, tex_co, num);
-		MEM_freeN(v_co);
+		get_texture_coords_mesh(&t_map, ob, mesh, tex_co);
 
 		modifier_init_texture(scene, texture);
 
@@ -209,9 +207,11 @@ void weightvg_do_mask(int num, const int *indices, float *org_w, const float *ne
 
 		/* Proceed only if vgroup is valid, else use constant factor. */
 		/* Get actual dverts (ie vertex group data). */
-		dvert = dm->getVertDataArray(dm, CD_MDEFORMVERT);
+		dvert = CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
 		/* Proceed only if vgroup is valid, else assume factor = O. */
-		if (dvert == NULL) return;
+		if (dvert == NULL) {
+			return;
+		}
 
 		/* For each weight (vertex), make the mix between org and new weights. */
 		for (i = 0; i < num; i++) {
diff --git a/source/blender/modifiers/intern/MOD_weightvg_util.h b/source/blender/modifiers/intern/MOD_weightvg_util.h
index 03bcbb6eb97..73552e50d0f 100644
--- a/source/blender/modifiers/intern/MOD_weightvg_util.h
+++ b/source/blender/modifiers/intern/MOD_weightvg_util.h
@@ -32,7 +32,9 @@
 #define __MOD_WEIGHTVG_UTIL_H__
 
 struct CurveMapping;
-struct DerivedMesh;
+struct MDeformVert;
+struct MDeformWeight;
+struct Mesh;
 struct Object;
 struct Tex;
 struct Scene;
@@ -70,16 +72,16 @@ void weightvg_do_map(int num, float *new_w, short mode, struct CurveMapping *cma
  * vertex index (in case the weight tables do not cover the whole vertices...).
  * XXX The standard "factor" value is assumed in [0.0, 1.0] range. Else, weird results might appear.
  */
-void weightvg_do_mask(int num, const int *indices, float *org_w, const float *new_w, Object *ob,
-                      DerivedMesh *dm, float fact, const char defgrp_name[MAX_VGROUP_NAME],
-                      struct Scene *scene, Tex *texture, int tex_use_channel, int tex_mapping,
+void weightvg_do_mask(const int num, const int *indices, float *org_w, const float *new_w, Object *ob,
+                      struct Mesh *mesh, const float fact, const char defgrp_name[MAX_VGROUP_NAME],
+                      struct Scene *scene, Tex *texture, const int tex_use_channel, const int tex_mapping,
                       Object *tex_map_object, const char *tex_uvlayer_name);
 
 /* Applies weights to given vgroup (defgroup), and optionally add/remove vertices from the group.
  * If indices is not NULL, it must be a table of same length as weights, mapping to the real
  * vertex index (in case the weight table does not cover the whole vertices...).
  */
-void weightvg_update_vg(MDeformVert *dvert, int defgrp_idx, MDeformWeight **dws, int num,
+void weightvg_update_vg(struct MDeformVert *dvert, int defgrp_idx, struct MDeformWeight **dws, int num,
                         const int *indices, const float *weights, const bool do_add,
                         const float add_thresh, const bool do_rem, const float rem_thresh);
 
diff --git a/source/blender/modifiers/intern/MOD_weightvgedit.c b/source/blender/modifiers/intern/MOD_weightvgedit.c
index 1a9651909dd..cc000cbee09 100644
--- a/source/blender/modifiers/intern/MOD_weightvgedit.c
+++ b/source/blender/modifiers/intern/MOD_weightvgedit.c
@@ -34,11 +34,11 @@
 #include "BLI_rand.h"
 
 #include "DNA_color_types.h"      /* CurveMapping. */
+#include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
 #include "DNA_modifier_types.h"
 #include "DNA_object_types.h"
 
-#include "BKE_cdderivedmesh.h"
 #include "BKE_colortools.h"       /* CurveMapping. */
 #include "BKE_deform.h"
 #include "BKE_library.h"
@@ -154,19 +154,18 @@ static bool isDisabled(ModifierData *md, int UNUSED(useRenderParams))
 	return (wmd->defgrp_name[0] == '\0');
 }
 
-static DerivedMesh *applyModifier(ModifierData *md,
+static Mesh *applyModifier(ModifierData *md,
                                   const ModifierEvalContext *ctx,
-                                  DerivedMesh *derivedData)
+                                  Mesh *mesh)
 {
 	WeightVGEditModifierData *wmd = (WeightVGEditModifierData *) md;
-	DerivedMesh *dm = derivedData;
+
 	MDeformVert *dvert = NULL;
 	MDeformWeight **dw = NULL;
 	float *org_w; /* Array original weights. */
 	float *new_w; /* Array new weights. */
-	int numVerts;
-	int defgrp_index;
 	int i;
+
 	/* Flags. */
 	const bool do_add  = (wmd->edit_flags & MOD_WVG_EDIT_ADD2VG) != 0;
 	const bool do_rem  = (wmd->edit_flags & MOD_WVG_EDIT_REMFVG) != 0;
@@ -176,30 +175,50 @@ static DerivedMesh *applyModifier(ModifierData *md,
 #endif
 
 	/* Get number of verts. */
-	numVerts = dm->getNumVerts(dm);
+	const int numVerts = mesh->totvert;
 
 	/* Check if we can just return the original mesh.
 	 * Must have verts and therefore verts assigned to vgroups to do anything useful!
 	 */
-	if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase))
-		return dm;
+	if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase)) {
+		return mesh;
+	}
 
 	/* Get vgroup idx from its name. */
-	defgrp_index = defgroup_name_index(ctx->object, wmd->defgrp_name);
-	if (defgrp_index == -1)
-		return dm;
+	const int defgrp_index = defgroup_name_index(ctx->object, wmd->defgrp_name);
+	if (defgrp_index == -1) {
+		return mesh;
+	}
 
-	dvert = CustomData_duplicate_referenced_layer(&dm->vertData, CD_MDEFORMVERT, numVerts);
+	const bool has_mdef = CustomData_has_layer(&mesh->vdata, CD_MDEFORMVERT);
 	/* If no vertices were ever added to an object's vgroup, dvert might be NULL. */
-	if (!dvert) {
+	if (!has_mdef) {
 		/* If this modifier is not allowed to add vertices, just return. */
-		if (!do_add)
-			return dm;
-		/* Else, add a valid data layer! */
-		dvert = CustomData_add_layer(&dm->vertData, CD_MDEFORMVERT, CD_CALLOC, NULL, numVerts);
-		/* Ultimate security check. */
-		if (!dvert)
-			return dm;
+		if (!do_add) {
+			return mesh;
+		}
+	}
+
+	Mesh *result;
+	BKE_id_copy_ex(
+	            NULL, &mesh->id, (ID **)&result,
+	            LIB_ID_CREATE_NO_MAIN |
+	            LIB_ID_CREATE_NO_USER_REFCOUNT |
+	            LIB_ID_CREATE_NO_DEG_TAG|
+	            LIB_ID_COPY_NO_PREVIEW,
+	            false);
+
+	if (has_mdef) {
+		dvert = CustomData_get_layer(&result->vdata, CD_MDEFORMVERT);
+	}
+	else {
+		/* Add a valid data layer! */
+		dvert = CustomData_add_layer(&result->vdata, CD_MDEFORMVERT, CD_CALLOC, NULL, numVerts);
+	}
+	/* Ultimate security check. */
+	if (!dvert) {
+		BKE_id_free(NULL, result);
+		return mesh;
 	}
 
 	/* Get org weights, assuming 0.0 for vertices not in given vgroup. */
@@ -220,17 +239,19 @@ static DerivedMesh *applyModifier(ModifierData *md,
 	if (wmd->falloff_type != MOD_WVG_MAPPING_NONE) {
 		RNG *rng = NULL;
 
-		if (wmd->falloff_type == MOD_WVG_MAPPING_RANDOM)
+		if (wmd->falloff_type == MOD_WVG_MAPPING_RANDOM) {
 			rng = BLI_rng_new_srandom(BLI_ghashutil_strhash(ctx->object->id.name + 2));
+		}
 
 		weightvg_do_map(numVerts, new_w, wmd->falloff_type, wmd->cmap_curve, rng);
 
-		if (rng)
+		if (rng) {
 			BLI_rng_free(rng);
+		}
 	}
 
 	/* Do masking. */
-	weightvg_do_mask(numVerts, NULL, org_w, new_w, ctx->object, dm, wmd->mask_constant,
+	weightvg_do_mask(numVerts, NULL, org_w, new_w, ctx->object, result, wmd->mask_constant,
 	                 wmd->mask_defgrp_name, wmd->modifier.scene, wmd->mask_texture,
 	                 wmd->mask_tex_use_channel, wmd->mask_tex_mapping,
 	                 wmd->mask_tex_map_obj, wmd->mask_tex_uvlayer_name);
@@ -251,7 +272,7 @@ static DerivedMesh *applyModifier(ModifierData *md,
 	MEM_freeN(dw);
 
 	/* Return the vgroup-modified mesh. */
-	return dm;
+	return result;
 }
 
 
@@ -271,14 +292,14 @@ ModifierTypeInfo modifierType_WeightVGEdit = {
 	/* deformMatrices_DM */ NULL,
 	/* deformVertsEM_DM */  NULL,
 	/* deformMatricesEM_DM*/NULL,
-	/* applyModifier_DM */  applyModifier,
+	/* applyModifier_DM */  NULL,
 	/* applyModifierEM_DM */NULL,
 
 	/* deformVerts */       NULL,
 	/* deformMatrices */    NULL,
 	/* deformVertsEM */     NULL,
 	/* deformMatricesEM */  NULL,
-	/* applyModifier */     NULL,
+	/* applyModifier */     applyModifier,
 	/* applyModifierEM */   NULL,
 
 	/* initData */          initData,
diff --git a/source/blender/modifiers/intern/MOD_weightvgmix.c b/source/blender/modifiers/intern/MOD_weightvgmix.c
index 9f32d5c6e30..2ea721c1982 100644
--- a/source/blender/modifiers/intern/MOD_weightvgmix.c
+++ b/source/blender/modifiers/intern/MOD_weightvgmix.c
@@ -32,11 +32,12 @@
 #include "BLI_math.h"
 #include "BLI_listbase.h"
 
+#include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
 #include "DNA_modifier_types.h"
 #include "DNA_object_types.h"
 
-#include "BKE_cdderivedmesh.h"
+#include "BKE_customdata.h"
 #include "BKE_deform.h"
 #include "BKE_library.h"
 #include "BKE_library_query.h"
@@ -201,15 +202,12 @@ static bool isDisabled(ModifierData *md, int UNUSED(useRenderParams))
 	return (wmd->defgrp_name_a[0] == '\0');
 }
 
-static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *ctx,
-                                  DerivedMesh *derivedData)
+static Mesh *applyModifier(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mesh)
 {
 	WeightVGMixModifierData *wmd = (WeightVGMixModifierData *) md;
-	DerivedMesh *dm = derivedData;
+
 	MDeformVert *dvert = NULL;
 	MDeformWeight **dw1, **tdw1, **dw2, **tdw2;
-	int numVerts;
-	int defgrp_index, defgrp_index_other = -1;
 	float *org_w;
 	float *new_w;
 	int *tidx, *indices = NULL;
@@ -221,37 +219,60 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 #endif
 
 	/* Get number of verts. */
-	numVerts = dm->getNumVerts(dm);
+	const int numVerts = mesh->totvert;
 
 	/* Check if we can just return the original mesh.
 	 * Must have verts and therefore verts assigned to vgroups to do anything useful!
 	 */
-	if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase))
-		return dm;
+	if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase)) {
+		return mesh;
+	}
 
 	/* Get vgroup idx from its name. */
-	defgrp_index = defgroup_name_index(ctx->object, wmd->defgrp_name_a);
-	if (defgrp_index == -1)
-		return dm;
+	const int defgrp_index = defgroup_name_index(ctx->object, wmd->defgrp_name_a);
+	if (defgrp_index == -1) {
+		return mesh;
+	}
 	/* Get second vgroup idx from its name, if given. */
-	if (wmd->defgrp_name_b[0] != (char)0) {
+	int defgrp_index_other = -1;
+	if (wmd->defgrp_name_b[0] != '\0') {
 		defgrp_index_other = defgroup_name_index(ctx->object, wmd->defgrp_name_b);
-		if (defgrp_index_other == -1)
-			return dm;
+		if (defgrp_index_other == -1) {
+			return mesh;
+		}
 	}
 
-	dvert = CustomData_duplicate_referenced_layer(&dm->vertData, CD_MDEFORMVERT, numVerts);
+	const bool has_mdef = CustomData_has_layer(&mesh->vdata, CD_MDEFORMVERT);
 	/* If no vertices were ever added to an object's vgroup, dvert might be NULL. */
-	if (!dvert) {
+	if (!has_mdef) {
 		/* If not affecting all vertices, just return. */
-		if (wmd->mix_set != MOD_WVG_SET_ALL)
-			return dm;
-		/* Else, add a valid data layer! */
-		dvert = CustomData_add_layer(&dm->vertData, CD_MDEFORMVERT, CD_CALLOC, NULL, numVerts);
-		/* Ultimate security check. */
-		if (!dvert)
-			return dm;
+		if (wmd->mix_set != MOD_WVG_SET_ALL) {
+			return mesh;
+		}
+	}
+
+	Mesh *result;
+	BKE_id_copy_ex(
+	            NULL, &mesh->id, (ID **)&result,
+	            LIB_ID_CREATE_NO_MAIN |
+	            LIB_ID_CREATE_NO_USER_REFCOUNT |
+	            LIB_ID_CREATE_NO_DEG_TAG|
+	            LIB_ID_COPY_NO_PREVIEW,
+	            false);
+
+	if (has_mdef) {
+		dvert = CustomData_get_layer(&result->vdata, CD_MDEFORMVERT);
 	}
+	else {
+		/* Add a valid data layer! */
+		dvert = CustomData_add_layer(&result->vdata, CD_MDEFORMVERT, CD_CALLOC, NULL, numVerts);
+	}
+	/* Ultimate security check. */
+	if (!dvert) {
+		BKE_id_free(NULL, result);
+		return mesh;
+	}
+
 	/* Find out which vertices to work on. */
 	tidx = MEM_malloc_arrayN(numVerts, sizeof(int), "WeightVGMix Modifier, tidx");
 	tdw1 = MEM_malloc_arrayN(numVerts, sizeof(MDeformWeight *), "WeightVGMix Modifier, tdw1");
@@ -318,7 +339,8 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 		MEM_freeN(tdw1);
 		MEM_freeN(tdw2);
 		MEM_freeN(tidx);
-		return dm;
+		BKE_id_free(NULL, result);
+		return mesh;
 	}
 	if (numIdx != -1) {
 		indices = MEM_malloc_arrayN(numIdx, sizeof(int), "WeightVGMix Modifier, indices");
@@ -352,7 +374,7 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 	}
 
 	/* Do masking. */
-	weightvg_do_mask(numIdx, indices, org_w, new_w, ctx->object, dm, wmd->mask_constant,
+	weightvg_do_mask(numIdx, indices, org_w, new_w, ctx->object, result, wmd->mask_constant,
 	                 wmd->mask_defgrp_name, wmd->modifier.scene, wmd->mask_texture,
 	                 wmd->mask_tex_use_channel, wmd->mask_tex_mapping,
 	                 wmd->mask_tex_map_obj, wmd->mask_tex_uvlayer_name);
@@ -373,12 +395,10 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 	MEM_freeN(new_w);
 	MEM_freeN(dw1);
 	MEM_freeN(dw2);
-
-	if (indices)
-		MEM_freeN(indices);
+	MEM_SAFE_FREE(indices);
 
 	/* Return the vgroup-modified mesh. */
-	return dm;
+	return result;
 }
 
 
@@ -398,14 +418,14 @@ ModifierTypeInfo modifierType_WeightVGMix = {
 	/* deformMatrices_DM */ NULL,
 	/* deformVertsEM_DM */  NULL,
 	/* deformMatricesEM_DM*/NULL,
-	/* applyModifier_DM */  applyModifier,
+	/* applyModifier_DM */  NULL,
 	/* applyModifierEM_DM */NULL,
 
 	/* deformVerts */       NULL,
 	/* deformMatrices */    NULL,
 	/* deformVertsEM */     NULL,
 	/* deformMatricesEM */  NULL,
-	/* applyModifier */     NULL,
+	/* applyModifier */     applyModifier,
 	/* applyModifierEM */   NULL,
 
 	/* initData */          initData,
diff --git a/source/blender/modifiers/intern/MOD_weightvgproximity.c b/source/blender/modifiers/intern/MOD_weightvgproximity.c
index b0416ed9f7a..85d647c3f41 100644
--- a/source/blender/modifiers/intern/MOD_weightvgproximity.c
+++ b/source/blender/modifiers/intern/MOD_weightvgproximity.c
@@ -41,9 +41,11 @@
 #include "DNA_object_types.h"
 
 #include "BKE_cdderivedmesh.h"
+#include "BKE_customdata.h"
 #include "BKE_deform.h"
 #include "BKE_library.h"
 #include "BKE_library_query.h"
+#include "BKE_mesh.h"
 #include "BKE_modifier.h"
 #include "BKE_texture.h"          /* Texture masking. */
 
@@ -53,6 +55,7 @@
 
 #include "MOD_weightvg_util.h"
 #include "MOD_modifiertypes.h"
+#include "MOD_util.h"
 
 //#define USE_TIMEIT
 
@@ -137,7 +140,7 @@ static void vert2geom_task_cb_ex(
  */
 static void get_vert2geom_distance(int numVerts, float (*v_cos)[3],
                                    float *dist_v, float *dist_e, float *dist_f,
-                                   DerivedMesh *target, const SpaceTransform *loc2trgt)
+                                   Mesh *target, const SpaceTransform *loc2trgt)
 {
 	Vert2GeomData data = {0};
 	Vert2GeomDataChunk data_chunk = {{{0}}};
@@ -146,9 +149,12 @@ static void get_vert2geom_distance(int numVerts, float (*v_cos)[3],
 	BVHTreeFromMesh treeData_e = {NULL};
 	BVHTreeFromMesh treeData_f = {NULL};
 
+	/* XXX TODO horrible, but simpler for now, bvhtree needs some love first! */
+	DerivedMesh *target_dm = CDDM_from_mesh(target);
+
 	if (dist_v) {
 		/* Create a bvh-tree of the given target's verts. */
-		bvhtree_from_mesh_get(&treeData_v, target, BVHTREE_FROM_VERTS, 2);
+		bvhtree_from_mesh_get(&treeData_v, target_dm, BVHTREE_FROM_VERTS, 2);
 		if (treeData_v.tree == NULL) {
 			OUT_OF_MEMORY();
 			return;
@@ -156,7 +162,7 @@ static void get_vert2geom_distance(int numVerts, float (*v_cos)[3],
 	}
 	if (dist_e) {
 		/* Create a bvh-tree of the given target's edges. */
-		bvhtree_from_mesh_get(&treeData_e, target, BVHTREE_FROM_EDGES, 2);
+		bvhtree_from_mesh_get(&treeData_e, target_dm, BVHTREE_FROM_EDGES, 2);
 		if (treeData_e.tree == NULL) {
 			OUT_OF_MEMORY();
 			return;
@@ -164,7 +170,7 @@ static void get_vert2geom_distance(int numVerts, float (*v_cos)[3],
 	}
 	if (dist_f) {
 		/* Create a bvh-tree of the given target's faces. */
-		bvhtree_from_mesh_get(&treeData_f, target, BVHTREE_FROM_LOOPTRI, 2);
+		bvhtree_from_mesh_get(&treeData_f, target_dm, BVHTREE_FROM_LOOPTRI, 2);
 		if (treeData_f.tree == NULL) {
 			OUT_OF_MEMORY();
 			return;
@@ -197,6 +203,8 @@ static void get_vert2geom_distance(int numVerts, float (*v_cos)[3],
 		free_bvhtree_from_mesh(&treeData_e);
 	if (dist_f)
 		free_bvhtree_from_mesh(&treeData_f);
+
+	target_dm->release(target_dm);
 }
 
 /**
@@ -257,13 +265,15 @@ static void do_map(Object *ob, float *weights, const int nidx, const float min_d
 	if (!ELEM(mode, MOD_WVG_MAPPING_NONE, MOD_WVG_MAPPING_CURVE)) {
 		RNG *rng = NULL;
 
-		if (mode == MOD_WVG_MAPPING_RANDOM)
+		if (mode == MOD_WVG_MAPPING_RANDOM) {
 			rng = BLI_rng_new_srandom(BLI_ghashutil_strhash(ob->id.name + 2));
+		}
 
 		weightvg_do_map(nidx, weights, mode, NULL, rng);
 
-		if (rng)
+		if (rng) {
 			BLI_rng_free(rng);
+		}
 	}
 }
 
@@ -368,14 +378,11 @@ static bool isDisabled(ModifierData *md, int UNUSED(useRenderParams))
 	return (wmd->proximity_ob_target == NULL);
 }
 
-static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *ctx,
-                                  DerivedMesh *derivedData)
+static Mesh *applyModifier(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mesh)
 {
 	WeightVGProximityModifierData *wmd = (WeightVGProximityModifierData *) md;
-	DerivedMesh *dm = derivedData;
 	MDeformVert *dvert = NULL;
 	MDeformWeight **dw, **tdw;
-	int numVerts;
 	float (*v_cos)[3] = NULL; /* The vertices coordinates. */
 	Object *ob = ctx->object;
 	Object *obr = NULL; /* Our target object. */
@@ -396,32 +403,57 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 #endif
 
 	/* Get number of verts. */
-	numVerts = dm->getNumVerts(dm);
+	const int numVerts = mesh->totvert;
 
 	/* Check if we can just return the original mesh.
 	 * Must have verts and therefore verts assigned to vgroups to do anything useful!
 	 */
-	if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase))
-		return dm;
+	if ((numVerts == 0) || BLI_listbase_is_empty(&ctx->object->defbase)) {
+		return mesh;
+	}
 
 	/* Get our target object. */
 	obr = wmd->proximity_ob_target;
-	if (obr == NULL)
-		return dm;
+	if (obr == NULL) {
+		return mesh;
+	}
 
 	/* Get vgroup idx from its name. */
 	defgrp_index = defgroup_name_index(ob, wmd->defgrp_name);
-	if (defgrp_index == -1)
-		return dm;
+	if (defgrp_index == -1) {
+		return mesh;
+	}
 
-	dvert = CustomData_duplicate_referenced_layer(&dm->vertData, CD_MDEFORMVERT, numVerts);
-	/* If no vertices were ever added to an object's vgroup, dvert might be NULL.
-	 * As this modifier never add vertices to vgroup, just return. */
-	if (!dvert)
-		return dm;
+	const bool has_mdef = CustomData_has_layer(&mesh->vdata, CD_MDEFORMVERT);
+	/* If no vertices were ever added to an object's vgroup, dvert might be NULL. */
+	/* As this modifier never add vertices to vgroup, just return. */
+	if (!has_mdef) {
+		return mesh;
+	}
 
-	/* Find out which vertices to work on (all vertices in vgroup), and get their relevant weight.
-	 */
+	Mesh *result;
+	BKE_id_copy_ex(
+	            NULL, &mesh->id, (ID **)&result,
+	            LIB_ID_CREATE_NO_MAIN |
+	            LIB_ID_CREATE_NO_USER_REFCOUNT |
+	            LIB_ID_CREATE_NO_DEG_TAG|
+	            LIB_ID_COPY_NO_PREVIEW,
+	            false);
+
+	if (has_mdef) {
+		dvert = CustomData_get_layer(&result->vdata, CD_MDEFORMVERT);
+	}
+	else {
+		/* Add a valid data layer! */
+		dvert = CustomData_add_layer(&result->vdata, CD_MDEFORMVERT, CD_CALLOC, NULL, numVerts);
+	}
+	/* Ultimate security check. */
+	if (!dvert) {
+		BKE_id_free(NULL, result);
+		return mesh;
+	}
+
+	/* Find out which vertices to work on (all vertices in vgroup), and get their relevant weight. */
 	tidx = MEM_malloc_arrayN(numVerts, sizeof(int), "WeightVGProximity Modifier, tidx");
 	tw = MEM_malloc_arrayN(numVerts, sizeof(float), "WeightVGProximity Modifier, tw");
 	tdw = MEM_malloc_arrayN(numVerts, sizeof(MDeformWeight *), "WeightVGProximity Modifier, tdw");
@@ -438,7 +470,8 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 		MEM_freeN(tidx);
 		MEM_freeN(tw);
 		MEM_freeN(tdw);
-		return dm;
+		BKE_id_free(NULL, result);
+		return mesh;
 	}
 	if (numIdx != numVerts) {
 		indices = MEM_malloc_arrayN(numIdx, sizeof(int), "WeightVGProximity Modifier, indices");
@@ -458,25 +491,24 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 	MEM_freeN(tidx);
 
 	/* Get our vertex coordinates. */
-	v_cos = MEM_malloc_arrayN(numIdx, sizeof(float[3]), "WeightVGProximity Modifier, v_cos");
 	if (numIdx != numVerts) {
-		/* XXX In some situations, this code can be up to about 50 times more performant
-		 *     than simply using getVertCo for each affected vertex...
-		 */
-		float (*tv_cos)[3] = MEM_malloc_arrayN(numVerts, sizeof(float[3]), "WeightVGProximity Modifier, tv_cos");
-		dm->getVertCos(dm, tv_cos);
-		for (i = 0; i < numIdx; i++)
+		float (*tv_cos)[3] = BKE_mesh_vertexCos_get(result, NULL);
+		v_cos = MEM_malloc_arrayN(numIdx, sizeof(float[3]), "WeightVGProximity Modifier, v_cos");
+		for (i = 0; i < numIdx; i++) {
 			copy_v3_v3(v_cos[i], tv_cos[indices[i]]);
+		}
 		MEM_freeN(tv_cos);
 	}
-	else
-		dm->getVertCos(dm, v_cos);
+	else {
+		v_cos = BKE_mesh_vertexCos_get(result, NULL);
+	}
 
 	/* Compute wanted distances. */
 	if (wmd->proximity_mode == MOD_WVG_PROXIMITY_OBJECT) {
 		const float dist = get_ob2ob_distance(ob, obr);
-		for (i = 0; i < numIdx; i++)
+		for (i = 0; i < numIdx; i++) {
 			new_w[i] = dist;
+		}
 	}
 	else if (wmd->proximity_mode == MOD_WVG_PROXIMITY_GEOMETRY) {
 		const bool use_trgt_verts = (wmd->proximity_flags & MOD_WVG_PROXIMITY_GEOM_VERTS) != 0;
@@ -484,23 +516,10 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 		const bool use_trgt_faces = (wmd->proximity_flags & MOD_WVG_PROXIMITY_GEOM_FACES) != 0;
 
 		if (use_trgt_verts || use_trgt_edges || use_trgt_faces) {
-			DerivedMesh *target_dm = obr->derivedFinal;
-			bool free_target_dm = false;
-			if (!target_dm) {
-				if (ELEM(obr->type, OB_CURVE, OB_SURF, OB_FONT))
-					target_dm = CDDM_from_curve(obr);
-				else if (obr->type == OB_MESH) {
-					Mesh *me = (Mesh *)obr->data;
-					if (me->edit_btmesh)
-						target_dm = CDDM_from_editbmesh(me->edit_btmesh, false, false);
-					else
-						target_dm = CDDM_from_mesh(me);
-				}
-				free_target_dm = true;
-			}
+			Mesh *target_mesh = get_mesh_eval_for_modifier(obr, ctx->flag);
 
-			/* We must check that we do have a valid target_dm! */
-			if (target_dm) {
+			/* We must check that we do have a valid target_mesh! */
+			if (target_mesh) {
 				SpaceTransform loc2trgt;
 				float *dists_v = use_trgt_verts ? MEM_malloc_arrayN(numIdx, sizeof(float), "dists_v") : NULL;
 				float *dists_e = use_trgt_edges ? MEM_malloc_arrayN(numIdx, sizeof(float), "dists_e") : NULL;
@@ -508,7 +527,7 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 
 				BLI_SPACE_TRANSFORM_SETUP(&loc2trgt, ob, obr);
 				get_vert2geom_distance(numIdx, v_cos, dists_v, dists_e, dists_f,
-				                       target_dm, &loc2trgt);
+				                       target_mesh, &loc2trgt);
 				for (i = 0; i < numIdx; i++) {
 					new_w[i] = dists_v ? dists_v[i] : FLT_MAX;
 					if (dists_e)
@@ -516,10 +535,10 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 					if (dists_f)
 						new_w[i] = min_ff(dists_f[i], new_w[i]);
 				}
-				if (free_target_dm) target_dm->release(target_dm);
-				if (dists_v) MEM_freeN(dists_v);
-				if (dists_e) MEM_freeN(dists_e);
-				if (dists_f) MEM_freeN(dists_f);
+
+				MEM_SAFE_FREE(dists_v);
+				MEM_SAFE_FREE(dists_e);
+				MEM_SAFE_FREE(dists_f);
 			}
 			/* Else, fall back to default obj2vert behavior. */
 			else {
@@ -535,7 +554,7 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 	do_map(ob, new_w, numIdx, wmd->min_dist, wmd->max_dist, wmd->falloff_type);
 
 	/* Do masking. */
-	weightvg_do_mask(numIdx, indices, org_w, new_w, ob, dm, wmd->mask_constant,
+	weightvg_do_mask(numIdx, indices, org_w, new_w, ob, result, wmd->mask_constant,
 	                 wmd->mask_defgrp_name, wmd->modifier.scene, wmd->mask_texture,
 	                 wmd->mask_tex_use_channel, wmd->mask_tex_mapping,
 	                 wmd->mask_tex_map_obj, wmd->mask_tex_uvlayer_name);
@@ -553,16 +572,15 @@ static DerivedMesh *applyModifier(ModifierData *md, const ModifierEvalContext *c
 	MEM_freeN(org_w);
 	MEM_freeN(new_w);
 	MEM_freeN(dw);
-	if (indices)
-		MEM_freeN(indices);
 	MEM_freeN(v_cos);
+	MEM_SAFE_FREE(indices);
 
 #ifdef USE_TIMEIT
 	TIMEIT_END(perf);
 #endif
 
 	/* Return the vgroup-modified mesh. */
-	return dm;
+	return result;
 }
 
 
@@ -582,14 +600,14 @@ ModifierTypeInfo modifierType_WeightVGProximity = {
 	/* deformMatrices_DM */ NULL,
 	/* deformVertsEM_DM */  NULL,
 	/* deformMatricesEM_DM*/NULL,
-	/* applyModifier_DM */  applyModifier,
+	/* applyModifier_DM */  NULL,
 	/* applyModifierEM_DM */NULL,
 
 	/* deformVerts */       NULL,
 	/* deformMatrices */    NULL,
 	/* deformVertsEM */     NULL,
 	/* deformMatricesEM */  NULL,
-	/* applyModifier */     NULL,
+	/* applyModifier */     applyModifier,
 	/* applyModifierEM */   NULL,
 
 	/* initData */          initData,