Fix T101925: sculpt color painting not updating with Cycles viewport render

* External engines do not use the PBVH and need slower depsgraph updates.
* Final depsgraph tag after stroke finishes was missing for sculpt color
  painting, caused missing updates for other viewports as well as any
  modifiers or nodes on other objects using the colors.

source/blender/blenkernel/BKE_paint.h

@@ -886,7 +886,7 @@ void BKE_sculpt_sync_face_visibility_to_grids(struct Mesh *mesh, struct SubdivCC
  * Test if PBVH can be used directly for drawing, which is faster than
  * drawing the mesh and all updates that come with it.
  */
-bool BKE_sculptsession_use_pbvh_draw(const struct Object *ob, const struct View3D *v3d);
+bool BKE_sculptsession_use_pbvh_draw(const struct Object *ob, const struct RegionView3D *rv3d);
 
 enum {
   SCULPT_MASK_LAYER_CALC_VERT = (1 << 0),

source/blender/blenkernel/intern/paint.cc

@@ -2316,7 +2316,7 @@ void BKE_sculpt_bvh_update_from_ccg(PBVH *pbvh, SubdivCCG *subdiv_ccg)
                         &key);
 }
 
-bool BKE_sculptsession_use_pbvh_draw(const Object *ob, const View3D * /*v3d*/)
+bool BKE_sculptsession_use_pbvh_draw(const Object *ob, const RegionView3D *rv3d)
 {
   SculptSession *ss = ob->sculpt;
   if (ss == nullptr || ss->pbvh == nullptr || ss->mode_type != OB_MODE_SCULPT) {
@@ -2324,9 +2324,10 @@ bool BKE_sculptsession_use_pbvh_draw(const Object *ob, const View3D * /*v3d*/)
   }
 
   if (BKE_pbvh_type(ss->pbvh) == PBVH_FACES) {
-    /* Regular mesh only draws from PBVH without modifiers and shape keys. */
-
-    return !(ss->shapekey_active || ss->deform_modifiers_active);
+    /* Regular mesh only draws from PBVH without modifiers and shape keys, or for
+     * external engines that do not have access to the PBVH like Eevee does. */
+    const bool external_engine = rv3d && rv3d->render_engine != nullptr;
+    return !(ss->shapekey_active || ss->deform_modifiers_active || external_engine);
   }
 
   /* Multires and dyntopo always draw directly from the PBVH. */

source/blender/draw/engines/basic/basic_engine.c

@@ -182,7 +182,7 @@ static void basic_cache_populate(void *vedata, Object *ob)
     }
   }
 
-  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d) &&
+  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d) &&
                                !DRW_state_is_image_render();
   const bool do_cull = (draw_ctx->v3d &&
                         (draw_ctx->v3d->shading.flag & V3D_SHADING_BACKFACE_CULLING));

source/blender/draw/engines/eevee/eevee_materials.c

@@ -810,7 +810,7 @@ void EEVEE_materials_cache_populate(EEVEE_Data *vedata,
   const DRWContextState *draw_ctx = DRW_context_state_get();
   Scene *scene = draw_ctx->scene;
 
-  bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d) &&
+  bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d) &&
                          !DRW_state_is_image_render();
 
   if (ob->sculpt && ob->sculpt->pbvh) {

source/blender/draw/engines/overlay/overlay_facing.cc

@@ -43,7 +43,7 @@ void OVERLAY_facing_cache_populate(OVERLAY_Data *vedata, Object *ob)
   }
 
   const DRWContextState *draw_ctx = DRW_context_state_get();
-  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d) &&
+  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d) &&
                                !DRW_state_is_image_render();
   const bool is_xray = (ob->dtx & OB_DRAW_IN_FRONT) != 0;
 

source/blender/draw/engines/overlay/overlay_fade.cc

@@ -53,7 +53,7 @@ void OVERLAY_fade_cache_populate(OVERLAY_Data *vedata, Object *ob)
   }
 
   const DRWContextState *draw_ctx = DRW_context_state_get();
-  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d) &&
+  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d) &&
                                !DRW_state_is_image_render();
   const bool is_xray = (ob->dtx & OB_DRAW_IN_FRONT) != 0;
 

source/blender/draw/engines/overlay/overlay_mode_transfer.cc

@@ -85,7 +85,7 @@ void OVERLAY_mode_transfer_cache_populate(OVERLAY_Data *vedata, Object *ob)
   }
 
   const DRWContextState *draw_ctx = DRW_context_state_get();
-  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d) &&
+  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d) &&
                                !DRW_state_is_image_render();
   const bool is_xray = (ob->dtx & OB_DRAW_IN_FRONT) != 0;
 

source/blender/draw/engines/overlay/overlay_sculpt.cc

@@ -37,7 +37,7 @@ void OVERLAY_sculpt_cache_populate(OVERLAY_Data *vedata, Object *ob)
   struct GPUBatch *sculpt_overlays;
   PBVH *pbvh = ob->sculpt->pbvh;
 
-  const bool use_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d);
+  const bool use_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d);
 
   if (!pbvh) {
     /* It is possible to have SculptSession without PBVH. This happens, for example, when toggling

source/blender/draw/engines/overlay/overlay_wireframe.cc

@@ -276,7 +276,7 @@ void OVERLAY_wireframe_cache_populate(OVERLAY_Data *vedata,
   /* Don't do that in edit Mesh mode, unless there is a modifier preview. */
   if (use_wire && (!is_mesh || (!is_edit_mode || has_edit_mesh_cage))) {
     const bool is_sculpt_mode = ((ob->mode & OB_MODE_SCULPT) != 0) && (ob->sculpt != nullptr);
-    const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d) &&
+    const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d) &&
                                  !DRW_state_is_image_render();
     const bool is_instance = (ob->base_flag & BASE_FROM_DUPLI);
     const bool instance_parent_in_edit_mode = is_instance ? DRW_object_is_in_edit_mode(

source/blender/draw/engines/workbench/workbench_engine.c

@@ -267,7 +267,7 @@ static eV3DShadingColorType workbench_color_type_get(WORKBENCH_PrivateData *wpd,
 
   const DRWContextState *draw_ctx = DRW_context_state_get();
   const bool is_active = (ob == draw_ctx->obact);
-  const bool is_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->v3d) &&
+  const bool is_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d) &&
                               !DRW_state_is_image_render();
   const bool is_render = DRW_state_is_image_render() && (draw_ctx->v3d == NULL);
   const bool is_texpaint_mode = is_active && (wpd->ctx_mode == CTX_MODE_PAINT_TEXTURE);

source/blender/editors/sculpt_paint/sculpt.c

@@ -1121,8 +1121,8 @@ void SCULPT_tag_update_overlays(bContext *C)
 
   DEG_id_tag_update(&ob->id, ID_RECALC_SHADING);
 
-  View3D *v3d = CTX_wm_view3d(C);
-  if (!BKE_sculptsession_use_pbvh_draw(ob, v3d)) {
+  RegionView3D *rv3d = CTX_wm_region_view3d(C);
+  if (!BKE_sculptsession_use_pbvh_draw(ob, rv3d)) {
     DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
   }
 }
@@ -4813,12 +4813,12 @@ static bool sculpt_needs_connectivity_info(const Sculpt *sd,
 void SCULPT_stroke_modifiers_check(const bContext *C, Object *ob, const Brush *brush)
 {
   SculptSession *ss = ob->sculpt;
-  View3D *v3d = CTX_wm_view3d(C);
+  RegionView3D *rv3d = CTX_wm_region_view3d(C);
   Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
 
   bool need_pmap = sculpt_needs_connectivity_info(sd, brush, ss, 0);
   if (ss->shapekey_active || ss->deform_modifiers_active ||
-      (!BKE_sculptsession_use_pbvh_draw(ob, v3d) && need_pmap)) {
+      (!BKE_sculptsession_use_pbvh_draw(ob, rv3d) && need_pmap)) {
     Depsgraph *depsgraph = CTX_data_depsgraph_pointer(C);
     BKE_sculpt_update_object_for_edit(
         depsgraph, ob, need_pmap, false, SCULPT_tool_is_paint(brush->sculpt_tool));
@@ -5249,7 +5249,6 @@ void SCULPT_flush_update_step(bContext *C, SculptUpdateType update_flags)
   SculptSession *ss = ob->sculpt;
   ARegion *region = CTX_wm_region(C);
   MultiresModifierData *mmd = ss->multires.modifier;
-  View3D *v3d = CTX_wm_view3d(C);
   RegionView3D *rv3d = CTX_wm_region_view3d(C);
 
   if (rv3d) {
@@ -5274,7 +5273,7 @@ void SCULPT_flush_update_step(bContext *C, SculptUpdateType update_flags)
 
   /* Only current viewport matters, slower update for all viewports will
    * be done in sculpt_flush_update_done. */
-  if (!BKE_sculptsession_use_pbvh_draw(ob, v3d)) {
+  if (!BKE_sculptsession_use_pbvh_draw(ob, rv3d)) {
     /* Slow update with full dependency graph update and all that comes with it.
      * Needed when there are modifiers or full shading in the 3D viewport. */
     DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
@@ -5316,16 +5315,15 @@ void SCULPT_flush_update_done(const bContext *C, Object *ob, SculptUpdateType up
   /* After we are done drawing the stroke, check if we need to do a more
    * expensive depsgraph tag to update geometry. */
   wmWindowManager *wm = CTX_wm_manager(C);
-  View3D *current_v3d = CTX_wm_view3d(C);
-  RegionView3D *rv3d = CTX_wm_region_view3d(C);
+  RegionView3D *current_rv3d = CTX_wm_region_view3d(C);
   SculptSession *ss = ob->sculpt;
   Mesh *mesh = ob->data;
 
   /* Always needed for linked duplicates. */
   bool need_tag = (ID_REAL_USERS(&mesh->id) > 1);
 
-  if (rv3d) {
-    rv3d->rflag &= ~RV3D_PAINTING;
+  if (current_rv3d) {
+    current_rv3d->rflag &= ~RV3D_PAINTING;
   }
 
   LISTBASE_FOREACH (wmWindow *, win, &wm->windows) {
@@ -5335,16 +5333,17 @@ void SCULPT_flush_update_done(const bContext *C, Object *ob, SculptUpdateType up
       if (sl->spacetype != SPACE_VIEW3D) {
         continue;
       }
-      View3D *v3d = (View3D *)sl;
-      if (v3d != current_v3d) {
-        need_tag |= !BKE_sculptsession_use_pbvh_draw(ob, v3d);
-      }
 
       /* Tag all 3D viewports for redraw now that we are done. Others
        * viewports did not get a full redraw, and anti-aliasing for the
        * current viewport was deactivated. */
       LISTBASE_FOREACH (ARegion *, region, &area->regionbase) {
         if (region->regiontype == RGN_TYPE_WINDOW) {
+          RegionView3D *rv3d = region->regiondata;
+          if (rv3d != current_rv3d) {
+            need_tag |= !BKE_sculptsession_use_pbvh_draw(ob, rv3d);
+          }
+
           ED_region_tag_redraw(region);
         }
       }
@@ -5378,15 +5377,17 @@ void SCULPT_flush_update_done(const bContext *C, Object *ob, SculptUpdateType up
 
   BKE_sculpt_attributes_destroy_temporary_stroke(ob);
 
-  if (BKE_pbvh_type(ss->pbvh) == PBVH_BMESH) {
-    BKE_pbvh_bmesh_after_stroke(ss->pbvh);
-  }
+  if (update_flags & SCULPT_UPDATE_COORDS) {
+    if (BKE_pbvh_type(ss->pbvh) == PBVH_BMESH) {
+      BKE_pbvh_bmesh_after_stroke(ss->pbvh);
+    }
 
-  /* Optimization: if there is locked key and active modifiers present in */
-  /* the stack, keyblock is updating at each step. otherwise we could update */
-  /* keyblock only when stroke is finished. */
-  if (ss->shapekey_active && !ss->deform_modifiers_active) {
-    sculpt_update_keyblock(ob);
+    /* Optimization: if there is locked key and active modifiers present in */
+    /* the stack, keyblock is updating at each step. otherwise we could update */
+    /* keyblock only when stroke is finished. */
+    if (ss->shapekey_active && !ss->deform_modifiers_active) {
+      sculpt_update_keyblock(ob);
+    }
   }
 
   if (need_tag) {
@@ -5625,6 +5626,7 @@ static void sculpt_stroke_done(const bContext *C, struct PaintStroke *UNUSED(str
     }
     else {
       BKE_sculpt_attributes_destroy_temporary_stroke(ob);
+      SCULPT_flush_update_done(C, ob, SCULPT_UPDATE_COLOR);
     }
   }
   else {

source/blender/editors/sculpt_paint/sculpt_undo.c

@@ -857,7 +857,7 @@ static void sculpt_undo_restore_list(bContext *C, Depsgraph *depsgraph, ListBase
 {
   Scene *scene = CTX_data_scene(C);
   ViewLayer *view_layer = CTX_data_view_layer(C);
-  View3D *v3d = CTX_wm_view3d(C);
+  RegionView3D *rv3d = CTX_wm_region_view3d(C);
   BKE_view_layer_synced_ensure(scene, view_layer);
   Object *ob = BKE_view_layer_active_object_get(view_layer);
   SculptSession *ss = ob->sculpt;
@@ -911,7 +911,7 @@ static void sculpt_undo_restore_list(bContext *C, Depsgraph *depsgraph, ListBase
       }
 
       DEG_id_tag_update(&ob->id, ID_RECALC_SHADING);
-      if (!BKE_sculptsession_use_pbvh_draw(ob, v3d)) {
+      if (!BKE_sculptsession_use_pbvh_draw(ob, rv3d)) {
         DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
       }
 
@@ -1070,7 +1070,7 @@ static void sculpt_undo_restore_list(bContext *C, Depsgraph *depsgraph, ListBase
       }
     }
 
-    tag_update |= ID_REAL_USERS(ob->data) > 1 || !BKE_sculptsession_use_pbvh_draw(ob, v3d) ||
+    tag_update |= ID_REAL_USERS(ob->data) > 1 || !BKE_sculptsession_use_pbvh_draw(ob, rv3d) ||
                   ss->shapekey_active || ss->deform_modifiers_active;
 
     if (tag_update) {