Vertex/Weight Paint: Use PBVH for painting

2016 GSOC project by @nathanvollmer, see D2150

- Mirrored painting and radial symmetry, like in sculpt mode.
- Volume based splash prevention,
  which avoids painting vertices far away from the 3D brush location.
- Normal based splash prevention,
  which avoids painting vertices with normals opposite the normal
  at the 3D brush location.
- Blur mode now uses a nearest neighbor average.
- Average mode, which averages the color/weight
  of the vertices within the brush
- Smudge mode, which pulls the colors/weights
  along the direction of the brush
- RGB^2 color blending, which gives a more accurate
  blend between two colors
- multithreading support. (PBVH leaves are painted in parallel.)
- Foreground/background color picker in vertex paint

8 files changed, 72 insertions, 23 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index ace79f4125b..9dae4c5eae7 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -2663,7 +2663,7 @@ static void mesh_build_data(
 	ob->lastDataMask = dataMask;
 	ob->lastNeedMapping = need_mapping;
 
-	if ((ob->mode & OB_MODE_SCULPT) && ob->sculpt) {
+	if ((ob->mode & OB_MODE_ALL_SCULPT) && ob->sculpt) {
 		/* create PBVH immediately (would be created on the fly too,
 		 * but this avoids waiting on first stroke) */
 
diff --git a/source/blender/blenkernel/intern/cdderivedmesh.c b/source/blender/blenkernel/intern/cdderivedmesh.c
index 2c61cf28691..e97de07752e 100644
--- a/source/blender/blenkernel/intern/cdderivedmesh.c
+++ b/source/blender/blenkernel/intern/cdderivedmesh.c
@@ -662,6 +662,11 @@ static void cdDM_drawMappedFaces(
 
 	const int *index_mp_to_orig  = dm->getPolyDataArray(dm, CD_ORIGINDEX);
 
+	if (cddm->pbvh) {
+		if (G.debug_value == 14)
+			BKE_pbvh_draw_BB(cddm->pbvh);
+	}
+
 	/* fist, setup common buffers */
 	GPU_vertex_setup(dm);
 	GPU_triangle_setup(dm);
diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index d76ef613023..44058c989ff 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -2682,7 +2682,7 @@ void BKE_object_sculpt_modifiers_changed(Object *ob)
 {
 	SculptSession *ss = ob->sculpt;
 
-	if (ss) {
+	if (ss && ss->building_vp_handle == false) {
 		if (!ss->cache) {
 			/* we free pbvh on changes, except during sculpt since it can't deal with
 			 * changing PVBH node organization, we hope topology does not change in
@@ -2693,6 +2693,9 @@ void BKE_object_sculpt_modifiers_changed(Object *ob)
 			}
 
 			BKE_sculptsession_free_deformMats(ob->sculpt);
+
+			/* In vertex/weight paint, force maps to be rebuilt. */
+			BKE_sculptsession_free_vwpaint_data(ob->sculpt);
 		}
 		else {
 			PBVHNode **nodes;
diff --git a/source/blender/blenkernel/intern/paint.c b/source/blender/blenkernel/intern/paint.c
index 9fc2136df86..25ea6ad079f 100644
--- a/source/blender/blenkernel/intern/paint.c
+++ b/source/blender/blenkernel/intern/paint.c
@@ -673,6 +673,29 @@ void BKE_sculptsession_free_deformMats(SculptSession *ss)
 	MEM_SAFE_FREE(ss->deform_imats);
 }
 
+void BKE_sculptsession_free_vwpaint_data(struct SculptSession *ss)
+{
+	struct SculptVertexPaintGeomMap *gmap = NULL;
+	if (ss->mode_type == OB_MODE_VERTEX_PAINT) {
+		gmap = &ss->mode.vpaint.gmap;
+
+		MEM_SAFE_FREE(ss->mode.vpaint.previous_color);
+	}
+	else if (ss->mode_type == OB_MODE_WEIGHT_PAINT) {
+		gmap = &ss->mode.wpaint.gmap;
+
+		MEM_SAFE_FREE(ss->mode.wpaint.alpha_weight);
+		MEM_SAFE_FREE(ss->mode.wpaint.previous_weight);
+	}
+	else {
+		return;
+	}
+	MEM_SAFE_FREE(gmap->vert_to_loop);
+	MEM_SAFE_FREE(gmap->vert_map_mem);
+	MEM_SAFE_FREE(gmap->vert_to_poly);
+	MEM_SAFE_FREE(gmap->poly_map_mem);
+}
+
 /* Write out the sculpt dynamic-topology BMesh to the Mesh */
 static void sculptsession_bm_to_me_update_data_only(Object *ob, bool reorder)
 {
@@ -714,10 +737,7 @@ void BKE_sculptsession_bm_to_me_for_render(Object *object)
 			 */
 			BKE_object_free_derived_caches(object);
 
-			if (object->sculpt->pbvh) {
-				BKE_pbvh_free(object->sculpt->pbvh);
-				object->sculpt->pbvh = NULL;
-			}
+			MEM_SAFE_FREE(object->sculpt->pbvh);
 
 			sculptsession_bm_to_me_update_data_only(object, false);
 
@@ -764,6 +784,8 @@ void BKE_sculptsession_free(Object *ob)
 		if (ss->deform_imats)
 			MEM_freeN(ss->deform_imats);
 
+		BKE_sculptsession_free_vwpaint_data(ob->sculpt);
+
 		MEM_freeN(ss);
 
 		ob->sculpt = NULL;
@@ -848,6 +870,8 @@ void BKE_sculpt_update_mesh_elements(Scene *scene, Sculpt *sd, Object *ob,
 	ss->modifiers_active = sculpt_modifiers_active(scene, sd, ob);
 	ss->show_diffuse_color = (sd->flags & SCULPT_SHOW_DIFFUSE) != 0;
 
+	ss->building_vp_handle = false;
+
 	if (need_mask) {
 		if (mmd == NULL) {
 			if (!CustomData_has_layer(&me->vdata, CD_PAINT_MASK)) {
@@ -876,7 +900,8 @@ void BKE_sculpt_update_mesh_elements(Scene *scene, Sculpt *sd, Object *ob,
 
 	dm = mesh_get_derived_final(scene, ob, CD_MASK_BAREMESH);
 
-	if (mmd) {
+	/* VWPaint require mesh info for loop lookup, so require sculpt mode here */
+	if (mmd && ob->mode & OB_MODE_SCULPT) {
 		ss->multires = mmd;
 		ss->totvert = dm->getNumVerts(dm);
 		ss->totpoly = dm->getNumPolys(dm);
diff --git a/source/blender/blenkernel/intern/pbvh.c b/source/blender/blenkernel/intern/pbvh.c
index 53dfffe2b97..4b154d3301c 100644
--- a/source/blender/blenkernel/intern/pbvh.c
+++ b/source/blender/blenkernel/intern/pbvh.c
@@ -34,6 +34,7 @@
 
 #include "BKE_pbvh.h"
 #include "BKE_ccg.h"
+#include "BKE_subsurf.h"
 #include "BKE_DerivedMesh.h"
 #include "BKE_global.h"
 #include "BKE_mesh.h" /* for BKE_mesh_calc_normals */
@@ -606,6 +607,10 @@ void BKE_pbvh_build_grids(PBVH *bvh, CCGElem **grids,
 	MEM_freeN(prim_bbc);
 }
 
+void BKE_pbvh_set_ccgdm(PBVH *bvh, CCGDerivedMesh *ccgdm) {
+	bvh->ccgdm = ccgdm;
+}
+
 PBVH *BKE_pbvh_new(void)
 {
 	PBVH *bvh = MEM_callocN(sizeof(PBVH), "pbvh");
@@ -1156,7 +1161,7 @@ static void pbvh_update_draw_buffers(PBVH *bvh, PBVHNode **nodes, int totnode)
 	}
 }
 
-static void pbvh_draw_BB(PBVH *bvh)
+void BKE_pbvh_draw_BB(PBVH *bvh)
 {
 	GPU_pbvh_BB_draw_init();
 
@@ -1329,6 +1334,11 @@ void BKE_pbvh_get_grid_key(const PBVH *bvh, CCGKey *key)
 	*key = bvh->gridkey;
 }
 
+CCGDerivedMesh *BKE_pbvh_get_ccgdm(const PBVH *bvh) {
+	return bvh->ccgdm;
+}
+
+
 BMesh *BKE_pbvh_get_bmesh(PBVH *bvh)
 {
 	BLI_assert(bvh->type == PBVH_BMESH);
@@ -1860,7 +1870,7 @@ void BKE_pbvh_draw(PBVH *bvh, float (*planes)[4], float (*fnors)[3],
 	}
 
 	if (G.debug_value == 14)
-		pbvh_draw_BB(bvh);
+		BKE_pbvh_draw_BB(bvh);
 }
 
 void BKE_pbvh_grids_update(PBVH *bvh, CCGElem **grids, void **gridfaces,
diff --git a/source/blender/blenkernel/intern/pbvh_intern.h b/source/blender/blenkernel/intern/pbvh_intern.h
index 19d3b31bd31..01057318568 100644
--- a/source/blender/blenkernel/intern/pbvh_intern.h
+++ b/source/blender/blenkernel/intern/pbvh_intern.h
@@ -149,6 +149,8 @@ struct PBVH {
 	 * objects in sculpt mode with different sizes at the same time, so now storing that common gpu buffer
 	 * in an opaque pointer per pbvh. See T47637. */
 	struct GridCommonGPUBuffer *grid_common_gpu_buffer;
+	/* The ccgdm is required for CD_ORIGINDEX lookup in vertex paint + multires */
+	struct CCGDerivedMesh *ccgdm;
 
 	/* Only used during BVH build and update,
 	 * don't need to remain valid after */
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index 5b809386267..c0dcac33656 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -217,16 +217,10 @@ void BKE_scene_copy_data(Main *bmain, Scene *sce_dst, const Scene *sce_src, cons
 		ToolSettings *ts = sce_dst->toolsettings = MEM_dupallocN(sce_dst->toolsettings);
 		if (ts->vpaint) {
 			ts->vpaint = MEM_dupallocN(ts->vpaint);
-			ts->vpaint->paintcursor = NULL;
-			ts->vpaint->vpaint_prev = NULL;
-			ts->vpaint->wpaint_prev = NULL;
 			BKE_paint_copy(&ts->vpaint->paint, &ts->vpaint->paint, flag_subdata);
 		}
 		if (ts->wpaint) {
 			ts->wpaint = MEM_dupallocN(ts->wpaint);
-			ts->wpaint->paintcursor = NULL;
-			ts->wpaint->vpaint_prev = NULL;
-			ts->wpaint->wpaint_prev = NULL;
 			BKE_paint_copy(&ts->wpaint->paint, &ts->wpaint->paint, flag_subdata);
 		}
 		if (ts->sculpt) {
@@ -335,16 +329,10 @@ Scene *BKE_scene_copy(Main *bmain, Scene *sce, int type)
 		if (ts) {
 			if (ts->vpaint) {
 				ts->vpaint = MEM_dupallocN(ts->vpaint);
-				ts->vpaint->paintcursor = NULL;
-				ts->vpaint->vpaint_prev = NULL;
-				ts->vpaint->wpaint_prev = NULL;
 				BKE_paint_copy(&ts->vpaint->paint, &ts->vpaint->paint, 0);
 			}
 			if (ts->wpaint) {
 				ts->wpaint = MEM_dupallocN(ts->wpaint);
-				ts->wpaint->paintcursor = NULL;
-				ts->wpaint->vpaint_prev = NULL;
-				ts->wpaint->wpaint_prev = NULL;
 				BKE_paint_copy(&ts->wpaint->paint, &ts->wpaint->paint, 0);
 			}
 			if (ts->sculpt) {
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index f4ff4dfa019..7c5ee42b7bc 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -3683,6 +3683,11 @@ static void ccgDM_drawMappedFaces(DerivedMesh *dm,
 	int gridFaces = gridSize - 1, totface;
 	int prev_mat_nr = -1;
 
+	if (ccgdm->pbvh) {
+		if (G.debug_value == 14)
+			BKE_pbvh_draw_BB(ccgdm->pbvh);
+	}
+
 #ifdef WITH_OPENSUBDIV
 	if (ccgdm->useGpuBackend) {
 		int new_matnr;
@@ -4416,7 +4421,8 @@ static struct PBVH *ccgDM_getPBVH(Object *ob, DerivedMesh *dm)
 	if (!ob->sculpt)
 		return NULL;
 
-	grid_pbvh = ccgDM_use_grid_pbvh(ccgdm);
+	/* In vwpaint, we always use a grid_pbvh for multires/subsurf */
+	grid_pbvh = (!(ob->mode & OB_MODE_SCULPT) || ccgDM_use_grid_pbvh(ccgdm));
 
 	if (ob->sculpt->pbvh) {
 		if (grid_pbvh) {
@@ -4432,12 +4438,18 @@ static struct PBVH *ccgDM_getPBVH(Object *ob, DerivedMesh *dm)
 		ccgdm->pbvh = ob->sculpt->pbvh;
 	}
 
-	if (ccgdm->pbvh)
+	if (ccgdm->pbvh) {
+		/* For vertex paint, keep track of ccgdm */
+		if (!(ob->mode & OB_MODE_SCULPT)) {
+			BKE_pbvh_set_ccgdm(ccgdm->pbvh, ccgdm);
+		}
 		return ccgdm->pbvh;
+	}
 
 	/* no pbvh exists yet, we need to create one. only in case of multires
 	 * we build a pbvh over the modified mesh, in other cases the base mesh
 	 * is being sculpted, so we build a pbvh from that. */
+	/* Note: vwpaint always builds a pbvh over the modified mesh. */
 	if (grid_pbvh) {
 		ccgdm_create_grids(dm);
 
@@ -4468,6 +4480,10 @@ static struct PBVH *ccgDM_getPBVH(Object *ob, DerivedMesh *dm)
 	if (ccgdm->pbvh)
 		pbvh_show_diffuse_color_set(ccgdm->pbvh, ob->sculpt->show_diffuse_color);
 
+	/* For vertex paint, keep track of ccgdm */
+	if (!(ob->mode & OB_MODE_SCULPT) && ccgdm->pbvh) {
+		BKE_pbvh_set_ccgdm(ccgdm->pbvh, ccgdm);
+	}
 	return ccgdm->pbvh;
 }