Workbench: Force Vertex Colors in Paint Mode

Vertex colors behaved differently as the paint overlay mixed the colors
in display mode and the results was multiplied on top of the original
shading.

This patch will align the implementation to texture painting where the
colors are drawn by the workbench engine so the correct shading is
applied.

This also means that we don't show the vertex colors overlay when not
in solid mode.

Reviewed By: fclem

Differential Revision: https://developer.blender.org/D6436

1 files changed, 61 insertions, 18 deletions

diff --git a/source/blender/draw/engines/workbench/workbench_materials.c b/source/blender/draw/engines/workbench/workbench_materials.c
index 28abed96b48..16fcda54253 100644
--- a/source/blender/draw/engines/workbench/workbench_materials.c
+++ b/source/blender/draw/engines/workbench/workbench_materials.c
@@ -85,16 +85,26 @@ void workbench_material_update_data(WORKBENCH_PrivateData *wpd,
 char *workbench_material_build_defines(WORKBENCH_PrivateData *wpd,
                                        bool is_uniform_color,
                                        bool is_hair,
-                                       bool is_texture_painting)
+                                       const WORKBENCH_ColorOverride color_override)
 {
   char *str = NULL;
   bool use_textures = (wpd->shading.color_type == V3D_SHADING_TEXTURE_COLOR) && !is_uniform_color;
   bool use_vertex_colors = (wpd->shading.color_type == V3D_SHADING_VERTEX_COLOR) &&
                            !is_uniform_color;
 
-  if (is_texture_painting) {
-    use_textures = true;
-    use_vertex_colors = false;
+  switch (color_override) {
+    case WORKBENCH_COLOR_OVERRIDE_TEXTURE:
+      use_textures = true;
+      use_vertex_colors = false;
+      is_hair = false;
+      break;
+    case WORKBENCH_COLOR_OVERRIDE_VERTEX:
+      use_textures = false;
+      use_vertex_colors = true;
+      is_hair = false;
+      break;
+    case WORKBENCH_COLOR_OVERRIDE_OFF:
+      break;
   }
 
   DynStr *ds = BLI_dynstr_new();
@@ -201,15 +211,25 @@ int workbench_material_get_composite_shader_index(WORKBENCH_PrivateData *wpd)
 int workbench_material_get_prepass_shader_index(WORKBENCH_PrivateData *wpd,
                                                 bool is_uniform_color,
                                                 bool is_hair,
-                                                bool is_texture_painting)
+                                                const WORKBENCH_ColorOverride color_override)
 {
   bool use_textures = (wpd->shading.color_type == V3D_SHADING_TEXTURE_COLOR) && !is_uniform_color;
   bool use_vertex_colors = (wpd->shading.color_type == V3D_SHADING_VERTEX_COLOR) &&
                            !is_uniform_color;
-  if (is_texture_painting) {
-    use_textures = true;
-    use_vertex_colors = false;
+
+  switch (color_override) {
+    case WORKBENCH_COLOR_OVERRIDE_TEXTURE:
+      use_textures = true;
+      use_vertex_colors = false;
+      break;
+    case WORKBENCH_COLOR_OVERRIDE_VERTEX:
+      use_textures = false;
+      use_vertex_colors = true;
+      break;
+    case WORKBENCH_COLOR_OVERRIDE_OFF:
+      break;
   }
+
   /* NOTE: change MAX_PREPASS_SHADERS accordingly when modifying this function. */
   int index = 0;
   SET_FLAG_FROM_TEST(index, is_hair, 1 << 0);
@@ -226,15 +246,25 @@ int workbench_material_get_prepass_shader_index(WORKBENCH_PrivateData *wpd,
 int workbench_material_get_accum_shader_index(WORKBENCH_PrivateData *wpd,
                                               bool is_uniform_color,
                                               bool is_hair,
-                                              bool is_texture_painting)
+                                              const WORKBENCH_ColorOverride color_override)
 {
   bool use_textures = (wpd->shading.color_type == V3D_SHADING_TEXTURE_COLOR) && !is_uniform_color;
   bool use_vertex_colors = (wpd->shading.color_type == V3D_SHADING_VERTEX_COLOR) &&
                            !is_uniform_color;
-  if (is_texture_painting) {
-    use_textures = true;
-    use_vertex_colors = false;
-    is_hair = false;
+
+  switch (color_override) {
+    case WORKBENCH_COLOR_OVERRIDE_TEXTURE:
+      use_textures = true;
+      use_vertex_colors = false;
+      is_hair = false;
+      break;
+    case WORKBENCH_COLOR_OVERRIDE_VERTEX:
+      use_textures = false;
+      use_vertex_colors = true;
+      is_hair = false;
+      break;
+    case WORKBENCH_COLOR_OVERRIDE_OFF:
+      break;
   }
 
   /* NOTE: change MAX_ACCUM_SHADERS accordingly when modifying this function. */
@@ -267,12 +297,25 @@ int workbench_material_determine_color_type(WORKBENCH_PrivateData *wpd,
     color_type = V3D_SHADING_OBJECT_COLOR;
   }
 
-  /* Force V3D_SHADING_TEXTURE_COLOR for active object when in texture painting
-   * no matter the shading color that the user has chosen, when there is no
-   * texture we will render the object with the error color */
-  if (workbench_is_object_in_texture_paint_mode(ob)) {
-    color_type = ima ? V3D_SHADING_TEXTURE_COLOR : V3D_SHADING_ERROR_COLOR;
+  switch (workbench_object_color_override_get(ob)) {
+    /* Force V3D_SHADING_TEXTURE_COLOR for active object when in texture painting
+     * no matter the shading color that the user has chosen, when there is no
+     * texture we will render the object with the error color */
+    case WORKBENCH_COLOR_OVERRIDE_TEXTURE:
+      color_type = ima ? V3D_SHADING_TEXTURE_COLOR : V3D_SHADING_ERROR_COLOR;
+      break;
+
+    /* Force V3D_SHADING_VERTEX_COLOR for active object when in vertex painting
+     * no matter the shading color that the user has chosen, when there is no
+     * vertex color we will render the object with the error color */
+    case WORKBENCH_COLOR_OVERRIDE_VERTEX:
+      color_type = V3D_SHADING_VERTEX_COLOR;
+      break;
+
+    case WORKBENCH_COLOR_OVERRIDE_OFF:
+      break;
   }
+
   return color_type;
 }