Fix part of #34640: vertex color blur brush would average face corner colors

at vertices for the entire mesh, which meant that discontinuous face colors
would be lost for unrelated parts of the mesh too. Now only vertices within
the brush radius will be affected.

1 files changed, 63 insertions, 17 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_vertex.c b/source/blender/editors/sculpt_paint/paint_vertex.c
index 7cc224db085..f245ec474f3 100644
--- a/source/blender/editors/sculpt_paint/paint_vertex.c
+++ b/source/blender/editors/sculpt_paint/paint_vertex.c
@@ -221,7 +221,7 @@ unsigned int vpaint_get_current_col(VPaint *vp)
 	return *(unsigned int *)col;
 }
 
-static void do_shared_vertex_tesscol(Mesh *me)
+static void do_shared_vertex_tesscol(Mesh *me, bool *mfacetag)
 {
 	/* if no mcol: do not do */
 	/* if tface: only the involved faces, otherwise all */
@@ -230,6 +230,7 @@ static void do_shared_vertex_tesscol(Mesh *me)
 	int a;
 	short *scolmain, *scol;
 	char *mcol;
+	bool *mftag;
 	
 	if (me->mcol == NULL || me->totvert == 0 || me->totface == 0) return;
 	
@@ -265,15 +266,25 @@ static void do_shared_vertex_tesscol(Mesh *me)
 
 	mface = me->mface;
 	mcol = (char *)me->mcol;
-	for (a = me->totface; a > 0; a--, mface++, mcol += 16) {
+	mftag = mfacetag;
+	for (a = me->totface; a > 0; a--, mface++, mcol += 16, mftag += 4) {
 		if ((use_face_sel == FALSE) || (mface->flag & ME_FACE_SEL)) {
-			scol = scolmain + 4 * mface->v1;
-			mcol[1] = scol[1]; mcol[2] = scol[2]; mcol[3] = scol[3];
-			scol = scolmain + 4 * mface->v2;
-			mcol[5] = scol[1]; mcol[6] = scol[2]; mcol[7] = scol[3];
-			scol = scolmain + 4 * mface->v3;
-			mcol[9] = scol[1]; mcol[10] = scol[2]; mcol[11] = scol[3];
-			if (mface->v4) {
+			if (mftag[0]) {
+				scol = scolmain + 4 * mface->v1;
+				mcol[1] = scol[1]; mcol[2] = scol[2]; mcol[3] = scol[3];
+			}
+
+			if (mftag[1]) {
+				scol = scolmain + 4 * mface->v2;
+				mcol[5] = scol[1]; mcol[6] = scol[2]; mcol[7] = scol[3];
+			}
+
+			if (mftag[2]) {
+				scol = scolmain + 4 * mface->v3;
+				mcol[9] = scol[1]; mcol[10] = scol[2]; mcol[11] = scol[3];
+			}
+
+			if (mface->v4 && mftag[3]) {
 				scol = scolmain + 4 * mface->v4;
 				mcol[13] = scol[1]; mcol[14] = scol[2]; mcol[15] = scol[3];
 			}
@@ -283,7 +294,7 @@ static void do_shared_vertex_tesscol(Mesh *me)
 	MEM_freeN(scolmain);
 }
 
-static void do_shared_vertexcol(Mesh *me, int do_tessface)
+static void do_shared_vertexcol(Mesh *me, bool *mlooptag, bool *mfacetag, int do_tessface)
 {
 	const int use_face_sel = (me->editflag & ME_EDIT_PAINT_FACE_SEL);
 	MPoly *mp;
@@ -325,9 +336,11 @@ static void do_shared_vertexcol(Mesh *me, int do_tessface)
 				MLoop *ml = me->mloop + mp->loopstart;
 				MLoopCol *lcol = me->mloopcol + mp->loopstart;
 				for (j = 0; j < mp->totloop; j++, ml++, lcol++) {
-					lcol->r = scol[ml->v][0];
-					lcol->g = scol[ml->v][1];
-					lcol->b = scol[ml->v][2];
+					if (mlooptag[mp->loopstart + j]) {
+						lcol->r = scol[ml->v][0];
+						lcol->g = scol[ml->v][1];
+						lcol->b = scol[ml->v][2];
+					}
 				}
 			}
 		}
@@ -336,7 +349,7 @@ static void do_shared_vertexcol(Mesh *me, int do_tessface)
 	MEM_freeN(scol);
 
 	if (has_shared && do_tessface) {
-		do_shared_vertex_tesscol(me);
+		do_shared_vertex_tesscol(me, mfacetag);
 	}
 }
 
@@ -2670,14 +2683,19 @@ typedef struct VPaintData {
 	DMCoNo *vertexcosnos;
 	float vpimat[3][3];
 
-	/* modify 'me->mcol' directly, since the derived mesh is drawing from this array,
-	 * otherwise we need to refresh the modifier stack */
+	/* modify 'me->mcol' directly, since the derived mesh is drawing from this
+	 * array, otherwise we need to refresh the modifier stack */
 	int use_fast_update;
 
 	/* mpoly -> mface mapping */
 	MemArena *polyfacemap_arena;
 	ListBase *polyfacemap;
 
+	/* loops tagged as having been painted, to apply shared vertex color
+	 * blending only to modified loops */
+	bool *mlooptag;
+	bool *mfacetag;
+
 	bool is_texbrush;
 } VPaintData;
 
@@ -2760,6 +2778,13 @@ static int vpaint_stroke_test_start(bContext *C, struct wmOperator *op, const fl
 /*		printf("No fast update!\n");*/
 	}
 
+	/* to keep tracked of modified loops for shared vertex color blending */
+	if (brush->vertexpaint_tool == PAINT_BLEND_BLUR) {
+		vpd->mlooptag = MEM_mallocN(sizeof(bool)*me->totloop, "VPaintData mlooptag");
+		if (vpd->use_fast_update)
+			vpd->mfacetag = MEM_mallocN(sizeof(bool)*me->totface*4, "VPaintData mfacetag");
+	}
+
 	/* for filtering */
 	copy_vpaint_prev(vp, (unsigned int *)me->mloopcol, me->totloop);
 	
@@ -2790,6 +2815,8 @@ static void vpaint_paint_poly(VPaint *vp, VPaintData *vpd, Mesh *me,
 	PolyFaceMap *e;
 	unsigned int *lcol = ((unsigned int *)me->mloopcol) + mpoly->loopstart;
 	unsigned int *lcolorig = ((unsigned int *)vp->vpaint_prev) + mpoly->loopstart;
+	bool *mlooptag = (vpd->mlooptag) ? vpd->mlooptag + mpoly->loopstart : NULL;
+	bool *mftag;
 	float alpha;
 	int i, j;
 	int totloop = mpoly->totloop;
@@ -2842,6 +2869,8 @@ static void vpaint_paint_poly(VPaint *vp, VPaintData *vpd, Mesh *me,
 		if (alpha > 0.0f) {
 			const int alpha_i = (int)(alpha * 255.0f);
 			lcol[i] = vpaint_blend(vp, lcol[i], lcolorig[i], paintcol, alpha_i, brush_alpha_pressure_i);
+
+			if (mlooptag) mlooptag[i] = 1;
 		}
 	}
 
@@ -2851,21 +2880,26 @@ static void vpaint_paint_poly(VPaint *vp, VPaintData *vpd, Mesh *me,
 		for (e = vpd->polyfacemap[index].first; e; e = e->next) {
 			mf = &me->mface[e->facenr];
 			mc = &me->mcol[e->facenr * 4];
+			mftag = &vpd->mfacetag[e->facenr * 4];
 
 			ml = me->mloop + mpoly->loopstart;
 			mlc = me->mloopcol + mpoly->loopstart;
 			for (j = 0; j < totloop; j++, ml++, mlc++) {
 				if (ml->v == mf->v1) {
 					MESH_MLOOPCOL_TO_MCOL(mlc, mc + 0);
+					if (mlooptag) mftag[0] = mlooptag[j];
 				}
 				else if (ml->v == mf->v2) {
 					MESH_MLOOPCOL_TO_MCOL(mlc, mc + 1);
+					if (mlooptag) mftag[1] = mlooptag[j];
 				}
 				else if (ml->v == mf->v3) {
 					MESH_MLOOPCOL_TO_MCOL(mlc, mc + 2);
+					if (mlooptag) mftag[2] = mlooptag[j];
 				}
 				else if (mf->v4 && ml->v == mf->v4) {
 					MESH_MLOOPCOL_TO_MCOL(mlc, mc + 3);
+					if (mlooptag) mftag[3] = mlooptag[j];
 				}
 			}
 		}
@@ -2923,6 +2957,12 @@ static void vpaint_stroke_update_step(bContext *C, struct PaintStroke *stroke, P
 	
 	swap_m4m4(vc->rv3d->persmat, mat);
 
+	/* clear modified tag for blur tool */
+	if(vpd->mlooptag)
+		memset(vpd->mlooptag, 0, sizeof(bool)*me->totloop);
+	if (vpd->mfacetag)
+		memset(vpd->mfacetag, 0, sizeof(bool)*me->totface*4);
+
 	for (index = 0; index < totindex; index++) {
 		if (indexar[index] && indexar[index] <= me->totpoly) {
 			vpaint_paint_poly(vp, vpd, me, indexar[index] - 1, mval, brush_size_pressure, brush_alpha_pressure);
@@ -2934,7 +2974,7 @@ static void vpaint_stroke_update_step(bContext *C, struct PaintStroke *stroke, P
 	/* was disabled because it is slow, but necessary for blur */
 	if (brush->vertexpaint_tool == PAINT_BLEND_BLUR) {
 		int do_tessface = vpd->use_fast_update;
-		do_shared_vertexcol(me, do_tessface);
+		do_shared_vertexcol(me, vpd->mlooptag, vpd->mfacetag, do_tessface);
 	}
 
 	{
@@ -2973,6 +3013,12 @@ static void vpaint_stroke_done(const bContext *C, struct PaintStroke *stroke)
 		BLI_memarena_free(vpd->polyfacemap_arena);
 	}
 
+	if (vpd->mlooptag)
+		MEM_freeN(vpd->mlooptag);
+
+	if (vpd->mfacetag)
+		MEM_freeN(vpd->mfacetag);
+
 	{
 		UnifiedPaintSettings *ups = &ts->unified_paint_settings;
 		ups->draw_pressure = false;