Fix #31199 & #31112: cycles not working well with vertex/weight paint selection

mask drawing.

Now refactored the code a bit so that in no longer calls textured mesh drawing
for the face mask drawing, just handle it as part of regular paint color drawing.
Should also make the blender internal behavior more logical where it would start
showing textures in solid mode when enabling face masking.

1 files changed, 56 insertions, 21 deletions

diff --git a/source/blender/editors/space_view3d/drawmesh.c b/source/blender/editors/space_view3d/drawmesh.c
index f5f3b4c3f16..e2a7478bc8f 100644
--- a/source/blender/editors/space_view3d/drawmesh.c
+++ b/source/blender/editors/space_view3d/drawmesh.c
@@ -179,7 +179,7 @@ static DMDrawOption draw_mesh_face_select__drawFaceOptsInv(void *userData, int i
 		return DM_DRAW_OPTION_SKIP;
 }
 
-static void draw_mesh_face_select(RegionView3D *rv3d, Mesh *me, DerivedMesh *dm)
+void draw_mesh_face_select(RegionView3D *rv3d, Mesh *me, DerivedMesh *dm)
 {
 	drawMeshFaceSelect_userData data;
 
@@ -593,20 +593,6 @@ static DMDrawOption draw_em_tf_mapped__set_draw(void *userData, int index)
 	}
 }
 
-static DMDrawOption wpaint__setSolidDrawOptions_material(void *userData, int index)
-{
-	Mesh *me = (Mesh *)userData;
-
-	if (me->mat && me->mpoly) {
-		Material *ma = me->mat[me->mpoly[index].mat_nr];
-		if (ma && (ma->game.flag & GEMAT_INVISIBLE)) {
-			return DM_DRAW_OPTION_SKIP;
-		}
-	}
-
-	return DM_DRAW_OPTION_NORMAL;
-}
-
 /* when face select is on, use face hidden flag */
 static DMDrawOption wpaint__setSolidDrawOptions_facemask(void *userData, int index)
 {
@@ -946,6 +932,10 @@ void draw_mesh_textured(Scene *scene, View3D *v3d, RegionView3D *rv3d, Object *o
 		draw_mesh_textured_old(scene, v3d, rv3d, ob, dm, draw_flags);
 		return;
 	}
+	else if (ob->mode & (OB_MODE_VERTEX_PAINT | OB_MODE_WEIGHT_PAINT)) {
+		draw_mesh_paint(scene, v3d, rv3d, ob, dm, draw_flags);
+		return;
+	}
 
 	/* set opengl state for negative scale & color */
 	if (ob->transflag & OB_NEG_SCALE) glFrontFace(GL_CW);
@@ -953,12 +943,7 @@ void draw_mesh_textured(Scene *scene, View3D *v3d, RegionView3D *rv3d, Object *o
 
 	glEnable(GL_LIGHTING);
 
-	if (ob->mode & (OB_MODE_VERTEX_PAINT | OB_MODE_WEIGHT_PAINT)) {
-		/* weight paint mode exception */
-		dm->drawMappedFaces(dm, wpaint__setSolidDrawOptions_material,
-		                    GPU_enable_material, NULL, ob->data, DM_DRAW_USE_COLORS | DM_DRAW_ALWAYS_SMOOTH);
-	}
-	else {
+	{
 		Mesh *me = ob->data;
 		TexMatCallback data = {scene, ob, me, dm};
 		int (*set_face_cb)(void *, int);
@@ -1015,3 +1000,53 @@ void draw_mesh_textured(Scene *scene, View3D *v3d, RegionView3D *rv3d, Object *o
 		draw_mesh_face_select(rv3d, ob->data, dm);
 }
 
+/* Vertex Paint and Weight Paint */
+
+void draw_mesh_paint(Scene *scene, View3D *v3d, RegionView3D *rv3d, Object *ob, DerivedMesh *dm, int draw_flags)
+{
+	DMSetDrawOptions facemask = NULL;
+	Mesh *me = ob->data;
+
+	/* hide faces in face select mode */
+	if (draw_flags & DRAW_FACE_SELECT)
+		facemask = wpaint__setSolidDrawOptions_facemask;
+
+	if (ob && ob->mode & OB_MODE_WEIGHT_PAINT) {
+		/* enforce default material settings */
+		GPU_enable_material(0, NULL);
+		
+		/* but set default spec */
+		glColorMaterial(GL_FRONT_AND_BACK, GL_SPECULAR);
+		glEnable(GL_COLOR_MATERIAL);    /* according manpages needed */
+		glColor3ub(120, 120, 120);
+		glDisable(GL_COLOR_MATERIAL);
+
+		/* diffuse */
+		glColorMaterial(GL_FRONT_AND_BACK, GL_DIFFUSE);
+		glEnable(GL_LIGHTING);
+		glEnable(GL_COLOR_MATERIAL);
+
+		dm->drawMappedFaces(dm, facemask, GPU_enable_material, NULL, me,
+							DM_DRAW_USE_COLORS | DM_DRAW_ALWAYS_SMOOTH);
+
+		glDisable(GL_COLOR_MATERIAL);
+		glDisable(GL_LIGHTING);
+
+		GPU_disable_material();
+	}
+	else if (ob->mode & OB_MODE_VERTEX_PAINT) {
+		if (me->mloopcol)
+			dm->drawMappedFaces(dm, facemask, GPU_enable_material, NULL, me,
+								DM_DRAW_USE_COLORS | DM_DRAW_ALWAYS_SMOOTH);
+		else {
+			glColor3f(1.0f, 1.0f, 1.0f);
+			dm->drawMappedFaces(dm, facemask, GPU_enable_material, NULL, me,
+								DM_DRAW_ALWAYS_SMOOTH);
+		}
+	}
+
+	/* draw face selection on top */
+	if (draw_flags & DRAW_FACE_SELECT)
+		draw_mesh_face_select(rv3d, me, dm);
+}
+