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, 75 insertions, 19 deletions

diff --git a/source/blender/draw/engines/workbench/workbench_deferred.c b/source/blender/draw/engines/workbench/workbench_deferred.c
index 31549c6f752..8c9dc43afa8 100644
--- a/source/blender/draw/engines/workbench/workbench_deferred.c
+++ b/source/blender/draw/engines/workbench/workbench_deferred.c
@@ -215,13 +215,16 @@ static GPUShader *workbench_cavity_shader_get(bool cavity, bool curvature)
 static GPUShader *ensure_deferred_prepass_shader(WORKBENCH_PrivateData *wpd,
                                                  bool is_uniform_color,
                                                  bool is_hair,
+                                                 bool is_texture_painting,
                                                  eGPUShaderConfig sh_cfg)
 {
   WORKBENCH_DEFERRED_Shaders *sh_data = &e_data.sh_data[sh_cfg];
-  int index = workbench_material_get_prepass_shader_index(wpd, is_uniform_color, is_hair);
+  int index = workbench_material_get_prepass_shader_index(
+      wpd, is_uniform_color, is_hair, is_texture_painting);
   if (sh_data->prepass_sh_cache[index] == NULL) {
     const GPUShaderConfigData *sh_cfg_data = &GPU_shader_cfg_data[sh_cfg];
-    char *defines = workbench_material_build_defines(wpd, is_uniform_color, is_hair);
+    char *defines = workbench_material_build_defines(
+        wpd, is_uniform_color, is_hair, is_texture_painting);
     char *prepass_vert = workbench_build_prepass_vert(is_hair);
     char *prepass_frag = workbench_build_prepass_frag();
     sh_data->prepass_sh_cache[index] = GPU_shader_create_from_arrays({
@@ -240,7 +243,7 @@ static GPUShader *ensure_deferred_composite_shader(WORKBENCH_PrivateData *wpd)
 {
   int index = workbench_material_get_composite_shader_index(wpd);
   if (e_data.composite_sh_cache[index] == NULL) {
-    char *defines = workbench_material_build_defines(wpd, false, false);
+    char *defines = workbench_material_build_defines(wpd, false, false, false);
     char *composite_frag = workbench_build_composite_frag(wpd);
     e_data.composite_sh_cache[index] = DRW_shader_create_fullscreen(composite_frag, defines);
     MEM_freeN(composite_frag);
@@ -267,10 +270,11 @@ static GPUShader *ensure_background_shader(WORKBENCH_PrivateData *wpd)
 
 static void select_deferred_shaders(WORKBENCH_PrivateData *wpd, eGPUShaderConfig sh_cfg)
 {
-  wpd->prepass_sh = ensure_deferred_prepass_shader(wpd, false, false, sh_cfg);
-  wpd->prepass_hair_sh = ensure_deferred_prepass_shader(wpd, false, true, sh_cfg);
-  wpd->prepass_uniform_sh = ensure_deferred_prepass_shader(wpd, true, false, sh_cfg);
-  wpd->prepass_uniform_hair_sh = ensure_deferred_prepass_shader(wpd, true, true, sh_cfg);
+  wpd->prepass_sh = ensure_deferred_prepass_shader(wpd, false, false, false, sh_cfg);
+  wpd->prepass_hair_sh = ensure_deferred_prepass_shader(wpd, false, true, false, sh_cfg);
+  wpd->prepass_uniform_sh = ensure_deferred_prepass_shader(wpd, true, false, false, sh_cfg);
+  wpd->prepass_uniform_hair_sh = ensure_deferred_prepass_shader(wpd, true, true, false, sh_cfg);
+  wpd->prepass_textured_sh = ensure_deferred_prepass_shader(wpd, false, false, true, sh_cfg);
   wpd->composite_sh = ensure_deferred_composite_shader(wpd);
   wpd->background_sh = ensure_background_shader(wpd);
 }
@@ -483,7 +487,7 @@ void workbench_deferred_engine_init(WORKBENCH_Data *vedata)
     e_data.composite_buffer_tx = DRW_texture_pool_query_2d(
         size[0], size[1], comp_tex_format, &draw_engine_workbench_solid);
 
-    if (MATDATA_PASS_ENABLED(wpd) || GPU_unused_fb_slot_workaround()) {
+    if (workbench_is_matdata_pass_enabled(wpd) || GPU_unused_fb_slot_workaround()) {
       e_data.color_buffer_tx = DRW_texture_pool_query_2d(
           size[0], size[1], col_tex_format, &draw_engine_workbench_solid);
     }
@@ -523,7 +527,7 @@ void workbench_deferred_engine_init(WORKBENCH_Data *vedata)
                                       GPU_ATTACHMENT_TEXTURE(e_data.composite_buffer_tx),
                                   });
 
-    if (!MATDATA_PASS_ENABLED(wpd) && !GPU_unused_fb_slot_workaround()) {
+    if (!workbench_is_matdata_pass_enabled(wpd) && !GPU_unused_fb_slot_workaround()) {
       e_data.color_buffer_tx = DRW_texture_pool_query_2d(
           size[0], size[1], col_tex_format, &draw_engine_workbench_solid);
     }
@@ -675,7 +679,7 @@ void workbench_deferred_engine_free(void)
 static void workbench_composite_uniforms(WORKBENCH_PrivateData *wpd, DRWShadingGroup *grp)
 {
   DRW_shgroup_uniform_block(grp, "world_block", wpd->world_ubo);
-  if (MATDATA_PASS_ENABLED(wpd)) {
+  if (workbench_is_matdata_pass_enabled(wpd)) {
     DRW_shgroup_uniform_texture_ref(grp, "materialBuffer", &e_data.color_buffer_tx);
   }
   else {
@@ -714,7 +718,6 @@ void workbench_deferred_cache_init(WORKBENCH_Data *vedata)
   Scene *scene = draw_ctx->scene;
 
   workbench_volume_cache_init(vedata);
-
   select_deferred_shaders(wpd, draw_ctx->sh_cfg);
 
   /* Background Pass */
@@ -869,7 +872,7 @@ static WORKBENCH_MaterialData *get_or_create_material_data(WORKBENCH_Data *vedat
   const bool is_ghost = (ob->dtx & OB_DRAWXRAY);
 
   /* Solid */
-  workbench_material_update_data(wpd, ob, mat, &material_template);
+  workbench_material_update_data(wpd, ob, mat, &material_template, color_type);
   material_template.object_id = OBJECT_ID_PASS_ENABLED(wpd) ? engine_object_data->object_id : 1;
   material_template.color_type = color_type;
   material_template.ima = ima;
@@ -880,9 +883,14 @@ static WORKBENCH_MaterialData *get_or_create_material_data(WORKBENCH_Data *vedat
   material = BLI_ghash_lookup(wpd->material_hash, POINTER_FROM_UINT(hash));
   if (material == NULL) {
     material = MEM_mallocN(sizeof(WORKBENCH_MaterialData), __func__);
+    /* select the correct prepass shader */
+    GPUShader *shader = (wpd->shading.color_type == color_type) ? wpd->prepass_sh :
+                                                                  wpd->prepass_uniform_sh;
+    if (color_type == V3D_SHADING_TEXTURE_COLOR) {
+      shader = wpd->prepass_textured_sh;
+    }
     material->shgrp = DRW_shgroup_create(
-        (wpd->shading.color_type == color_type) ? wpd->prepass_sh : wpd->prepass_uniform_sh,
-        (ob->dtx & OB_DRAWXRAY) ? psl->ghost_prepass_pass : psl->prepass_pass);
+        shader, (ob->dtx & OB_DRAWXRAY) ? psl->ghost_prepass_pass : psl->prepass_pass);
     workbench_material_copy(material, &material_template);
     DRW_shgroup_stencil_mask(material->shgrp, (ob->dtx & OB_DRAWXRAY) ? 0x00 : 0xFF);
     DRW_shgroup_uniform_int(material->shgrp, "object_id", &material->object_id, 1);
@@ -935,6 +943,49 @@ static void workbench_cache_populate_particles(WORKBENCH_Data *vedata, Object *o
   }
 }
 
+static void workbench_cache_populate_texture_paint_mode(WORKBENCH_Data *vedata, Object *ob)
+{
+  WORKBENCH_StorageList *stl = vedata->stl;
+  WORKBENCH_PrivateData *wpd = stl->g_data;
+  const DRWContextState *draw_ctx = DRW_context_state_get();
+
+  Scene *scene = draw_ctx->scene;
+  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d);
+  WORKBENCH_MaterialData *material;
+
+  /* Force workbench to render active object textured when in texture paint mode */
+  const ImagePaintSettings *imapaint = &scene->toolsettings->imapaint;
+
+  /* Single Image mode */
+  if (imapaint->mode == IMAGEPAINT_MODE_IMAGE) {
+    Image *image = imapaint->canvas;
+    int interp = (imapaint->interp == IMAGEPAINT_INTERP_LINEAR) ? SHD_INTERP_LINEAR :
+                                                                  SHD_INTERP_CLOSEST;
+    int color_type = workbench_material_determine_color_type(wpd, image, ob, use_sculpt_pbvh);
+    struct GPUBatch *geom = DRW_cache_mesh_surface_texpaint_single_get(ob);
+    material = get_or_create_material_data(vedata, ob, NULL, image, NULL, color_type, interp);
+
+    DRW_shgroup_call(material->shgrp, geom, ob);
+  }
+  else {
+    /* IMAGEPAINT_MODE_MATERIAL */
+    const int materials_len = MAX2(1, ob->totcol);
+    struct GPUBatch **geom_array = DRW_cache_mesh_surface_texpaint_get(ob);
+    for (int i = 0; i < materials_len; i++) {
+      if (geom_array != NULL && geom_array[i] != NULL) {
+        Material *mat;
+        Image *image;
+        ImageUser *iuser;
+        int interp;
+        workbench_material_get_image_and_mat(ob, i + 1, &image, &iuser, &interp, &mat);
+        int color_type = workbench_material_determine_color_type(wpd, image, ob, use_sculpt_pbvh);
+        material = get_or_create_material_data(vedata, ob, mat, image, iuser, color_type, interp);
+        DRW_shgroup_call(material->shgrp, geom_array[i], ob);
+      }
+    }
+  }
+}
+
 void workbench_deferred_solid_cache_populate(WORKBENCH_Data *vedata, Object *ob)
 {
   WORKBENCH_StorageList *stl = vedata->stl;
@@ -975,8 +1026,13 @@ void workbench_deferred_solid_cache_populate(WORKBENCH_Data *vedata, Object *ob)
     const int materials_len = MAX2(1, ob->totcol);
     const Mesh *me = (ob->type == OB_MESH) ? ob->data : NULL;
     bool has_transp_mat = false;
+    const bool use_texture_paint_drawing = workbench_is_object_in_texture_paint_mode(ob) && me &&
+                                           me->mloopuv;
 
-    if (!use_sculpt_pbvh && TEXTURE_DRAWING_ENABLED(wpd) && me && me->mloopuv) {
+    if (use_texture_paint_drawing) {
+      workbench_cache_populate_texture_paint_mode(vedata, ob);
+    }
+    else if (!use_sculpt_pbvh && TEXTURE_DRAWING_ENABLED(wpd) && me && me->mloopuv) {
       /* Draw textured */
       struct GPUBatch **geom_array = DRW_cache_mesh_surface_texpaint_get(ob);
       for (int i = 0; i < materials_len; i++) {
@@ -990,7 +1046,7 @@ void workbench_deferred_solid_cache_populate(WORKBENCH_Data *vedata, Object *ob)
               wpd, image, ob, use_sculpt_pbvh);
           if (color_type == V3D_SHADING_MATERIAL_COLOR && mat && mat->a < 1.0) {
             material = workbench_forward_get_or_create_material_data(
-                vedata, ob, mat, image, iuser, color_type, 0, use_sculpt_pbvh);
+                vedata, ob, mat, image, iuser, color_type, 0);
             has_transp_mat = true;
           }
           else {
@@ -1010,7 +1066,7 @@ void workbench_deferred_solid_cache_populate(WORKBENCH_Data *vedata, Object *ob)
 
       if ((ob->color[3] < 1.0f) && (color_type == V3D_SHADING_OBJECT_COLOR)) {
         material = workbench_forward_get_or_create_material_data(
-            vedata, ob, NULL, NULL, NULL, color_type, 0, use_sculpt_pbvh);
+            vedata, ob, NULL, NULL, NULL, color_type, 0);
         has_transp_mat = true;
       }
       else {
@@ -1045,7 +1101,7 @@ void workbench_deferred_solid_cache_populate(WORKBENCH_Data *vedata, Object *ob)
           struct Material *mat = give_current_material(ob, i + 1);
           if (mat != NULL && mat->a < 1.0f) {
             material = workbench_forward_get_or_create_material_data(
-                vedata, ob, mat, NULL, NULL, V3D_SHADING_MATERIAL_COLOR, 0, use_sculpt_pbvh);
+                vedata, ob, mat, NULL, NULL, V3D_SHADING_MATERIAL_COLOR, 0);
             has_transp_mat = true;
           }
           else {
@@ -1068,7 +1124,7 @@ void workbench_deferred_solid_cache_populate(WORKBENCH_Data *vedata, Object *ob)
             Material *mat = give_current_material(ob, i + 1);
             if (mat != NULL && mat->a < 1.0f) {
               material = workbench_forward_get_or_create_material_data(
-                  vedata, ob, mat, NULL, NULL, V3D_SHADING_MATERIAL_COLOR, 0, use_sculpt_pbvh);
+                  vedata, ob, mat, NULL, NULL, V3D_SHADING_MATERIAL_COLOR, 0);
               has_transp_mat = true;
             }
             else {