TexturePaint: Force Workbench Texture Color Mode

When in texture paint mode and in solid mode the object that is being
texture painted will be rendered by the workbench engine with textures.
All other objects would render the same. For other cases the texture paint
draw engine will still draw the texture.

The texture mode draw engine now only drawn the masks. The opacity
sliders influences the texture mask.

This change has been implemented conserably. In the future we need to
look into making this better, like adding support that every object
can be colored differently. Currently when rendering in the workbench
we can have up to 3 different color types active (what the user selected,
the fallback in case no materials have been configured and this one,
forcing textures)

Reviewed By: fclem, brecht

Differential Revision: https://developer.blender.org/D5190

1 files changed, 38 insertions, 8 deletions

diff --git a/source/blender/draw/engines/workbench/workbench_private.h b/source/blender/draw/engines/workbench/workbench_private.h
index 3b62ed33e96..17144c4dc10 100644
--- a/source/blender/draw/engines/workbench/workbench_private.h
+++ b/source/blender/draw/engines/workbench/workbench_private.h
@@ -43,6 +43,7 @@
 
 #define TEXTURE_DRAWING_ENABLED(wpd) (wpd->shading.color_type == V3D_SHADING_TEXTURE_COLOR)
 #define VERTEX_COLORS_ENABLED(wpd) (wpd->shading.color_type == V3D_SHADING_VERTEX_COLOR)
+#define MATERIAL_COLORS_ENABLED(wpd) (wpd->shading.color_type == V3D_SHADING_MATERIAL_COLOR)
 #define FLAT_ENABLED(wpd) (wpd->shading.light == V3D_LIGHTING_FLAT)
 #define STUDIOLIGHT_ENABLED(wpd) (wpd->shading.light == V3D_LIGHTING_STUDIO)
 #define MATCAP_ENABLED(wpd) (wpd->shading.light == V3D_LIGHTING_MATCAP)
@@ -81,8 +82,6 @@
    (!STUDIOLIGHT_TYPE_MATCAP_ENABLED(wpd)))
 #define OBJECT_OUTLINE_ENABLED(wpd) (wpd->shading.flag & V3D_SHADING_OBJECT_OUTLINE)
 #define OBJECT_ID_PASS_ENABLED(wpd) (OBJECT_OUTLINE_ENABLED(wpd) || CURVATURE_ENABLED(wpd))
-#define MATDATA_PASS_ENABLED(wpd) \
-  (wpd->shading.color_type != V3D_SHADING_SINGLE_COLOR || MATCAP_ENABLED(wpd))
 #define NORMAL_VIEWPORT_COMP_PASS_ENABLED(wpd) \
   (MATCAP_ENABLED(wpd) || STUDIOLIGHT_ENABLED(wpd) || SHADOW_ENABLED(wpd))
 #define NORMAL_VIEWPORT_PASS_ENABLED(wpd) \
@@ -208,12 +207,14 @@ typedef struct WORKBENCH_PrivateData {
   struct GPUShader *prepass_hair_sh;
   struct GPUShader *prepass_uniform_sh;
   struct GPUShader *prepass_uniform_hair_sh;
+  struct GPUShader *prepass_textured_sh;
   struct GPUShader *composite_sh;
   struct GPUShader *background_sh;
   struct GPUShader *transparent_accum_sh;
   struct GPUShader *transparent_accum_hair_sh;
   struct GPUShader *transparent_accum_uniform_sh;
   struct GPUShader *transparent_accum_uniform_hair_sh;
+  struct GPUShader *transparent_accum_textured_sh;
   View3DShading shading;
   StudioLight *studio_light;
   const UserDef *preferences;
@@ -354,6 +355,32 @@ BLI_INLINE bool workbench_is_fxaa_enabled(WORKBENCH_PrivateData *wpd)
   }
 }
 
+/** Is texture paint mode enabled (globally) */
+BLI_INLINE bool workbench_is_in_texture_paint_mode(void)
+{
+  const DRWContextState *draw_ctx = DRW_context_state_get();
+  return draw_ctx->object_mode == OB_MODE_TEXTURE_PAINT;
+}
+
+/** Is texture paint mode active for the given object */
+BLI_INLINE bool workbench_is_object_in_texture_paint_mode(Object *ob)
+{
+  const DRWContextState *draw_ctx = DRW_context_state_get();
+  if (ob->type == OB_MESH && (draw_ctx->obact == ob)) {
+    const enum eContextObjectMode mode = CTX_data_mode_enum_ex(
+        draw_ctx->object_edit, draw_ctx->obact, draw_ctx->object_mode);
+    return (mode == CTX_MODE_PAINT_TEXTURE);
+  }
+
+  return false;
+}
+
+BLI_INLINE bool workbench_is_matdata_pass_enabled(WORKBENCH_PrivateData *wpd)
+{
+  return (wpd->shading.color_type != V3D_SHADING_SINGLE_COLOR || MATCAP_ENABLED(wpd)) ||
+         workbench_is_in_texture_paint_mode();
+}
+
 /* workbench_deferred.c */
 void workbench_deferred_engine_init(WORKBENCH_Data *vedata);
 void workbench_deferred_engine_free(void);
@@ -383,8 +410,7 @@ WORKBENCH_MaterialData *workbench_forward_get_or_create_material_data(WORKBENCH_
                                                                       Image *ima,
                                                                       ImageUser *iuser,
                                                                       int color_type,
-                                                                      int interp,
-                                                                      bool use_sculpt_pbvh);
+                                                                      int interp);
 
 /* workbench_effect_aa.c */
 void workbench_aa_create_pass(WORKBENCH_Data *vedata, GPUTexture **tx);
@@ -422,19 +448,23 @@ void workbench_material_get_image_and_mat(
     Object *ob, int mat_nr, Image **r_image, ImageUser **r_iuser, int *r_interp, Material **r_mat);
 char *workbench_material_build_defines(WORKBENCH_PrivateData *wpd,
                                        bool is_uniform_color,
-                                       bool is_hair);
+                                       bool is_hair,
+                                       bool is_texture_painting);
 void workbench_material_update_data(WORKBENCH_PrivateData *wpd,
                                     Object *ob,
                                     Material *mat,
-                                    WORKBENCH_MaterialData *data);
+                                    WORKBENCH_MaterialData *data,
+                                    int color_type);
 uint workbench_material_get_hash(WORKBENCH_MaterialData *material_template, bool is_ghost);
 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_hair,
+                                                bool is_texture_painting);
 int workbench_material_get_accum_shader_index(WORKBENCH_PrivateData *wpd,
                                               bool is_uniform_color,
-                                              bool is_hair);
+                                              bool is_hair,
+                                              bool is_texture_painting);
 void workbench_material_shgroup_uniform(WORKBENCH_PrivateData *wpd,
                                         DRWShadingGroup *grp,
                                         WORKBENCH_MaterialData *material,