source/blender/editors/sculpt_paint/paint_vertex.cc

@@ -441,7 +441,14 @@ void smooth_brush_toggle_off(const bContext *C, Paint *paint, StrokeCache *cache
   /* The current brush should match with what we have stored in the cache. */
   BLI_assert(brush == cache->brush);
 
-  /* Try to switch back to the saved/previous brush. */
+  /* Note: used for both vertexpaint and weightpaint, VPAINT_TOOL_BLUR & WPAINT_TOOL_BLUR are the
+   * same, see comments for eBrushVertexPaintTool & eBrushWeightPaintTool. */
+  /* If the smooth (blur) brush is missing, brush was not switched/affected in
+   * smooth_brush_toggle_on(). */
+  if (!BKE_paint_toolslots_brush_get(paint, WPAINT_TOOL_BLUR)) {
+    return;
+  }
+
   BKE_brush_size_set(scene, brush, cache->saved_smooth_size);
   brush = (Brush *)BKE_libblock_find_name(bmain, ID_BR, cache->saved_active_brush_name);
   if (brush) {
@@ -590,19 +597,27 @@ void last_stroke_update(Scene *scene, const float location[3])
 void smooth_brush_toggle_on(const bContext *C, Paint *paint, StrokeCache *cache)
 {
   Scene *scene = CTX_data_scene(C);
-  Brush *brush = paint->brush;
-  int cur_brush_size = BKE_brush_size_get(scene, brush);
 
-  STRNCPY(cache->saved_active_brush_name, brush->id.name + 2);
-
-  /* Switch to the blur (smooth) brush. */
-  brush = BKE_paint_toolslots_brush_get(paint, WPAINT_TOOL_BLUR);
-  if (brush) {
-    BKE_paint_brush_set(paint, brush);
-    cache->saved_smooth_size = BKE_brush_size_get(scene, brush);
-    BKE_brush_size_set(scene, brush, cur_brush_size);
-    BKE_curvemapping_init(brush->curve);
+  /* Switch to the blur (smooth) brush if possible. */
+  /* Note: used for both vertexpaint and weightpaint, VPAINT_TOOL_BLUR & WPAINT_TOOL_BLUR are the
+   * same, see comments for eBrushVertexPaintTool & eBrushWeightPaintTool. */
+  Brush *smooth_brush = BKE_paint_toolslots_brush_get(paint, WPAINT_TOOL_BLUR);
+  if (!smooth_brush) {
+    printf(
+        "WARNING: Switching to the blur (smooth) brush not possible, corresponding brush not "
+        "found\n");
+    return;
   }
+
+  Brush *cur_brush = paint->brush;
+  int cur_brush_size = BKE_brush_size_get(scene, cur_brush);
+
+  STRNCPY(cache->saved_active_brush_name, cur_brush->id.name + 2);
+
+  BKE_paint_brush_set(paint, smooth_brush);
+  cache->saved_smooth_size = BKE_brush_size_get(scene, smooth_brush);
+  BKE_brush_size_set(scene, smooth_brush, cur_brush_size);
+  BKE_curvemapping_init(smooth_brush->curve);
 }
 /** \} */
 }  // namespace blender::ed::sculpt_paint::vwpaint

source/blender/editors/sculpt_paint/sculpt.cc

@@ -4345,34 +4345,37 @@ static void sculpt_init_mirror_clipping(Object *ob, SculptSession *ss)
 static void smooth_brush_toggle_on(const bContext *C, Paint *paint, StrokeCache *cache)
 {
   Scene *scene = CTX_data_scene(C);
-  Brush *brush = paint->brush;
+  Brush *cur_brush = paint->brush;
 
-  if (brush->sculpt_tool == SCULPT_TOOL_MASK) {
-    cache->saved_mask_brush_tool = brush->mask_tool;
-    brush->mask_tool = BRUSH_MASK_SMOOTH;
+  if (cur_brush->sculpt_tool == SCULPT_TOOL_MASK) {
+    cache->saved_mask_brush_tool = cur_brush->mask_tool;
+    cur_brush->mask_tool = BRUSH_MASK_SMOOTH;
   }
-  else if (ELEM(brush->sculpt_tool,
+  else if (ELEM(cur_brush->sculpt_tool,
                 SCULPT_TOOL_SLIDE_RELAX,
                 SCULPT_TOOL_DRAW_FACE_SETS,
                 SCULPT_TOOL_PAINT,
                 SCULPT_TOOL_SMEAR))
   {
     /* Do nothing, this tool has its own smooth mode. */
+    return;
   }
-  else {
-    int cur_brush_size = BKE_brush_size_get(scene, brush);
 
-    STRNCPY(cache->saved_active_brush_name, brush->id.name + 2);
-
-    /* Switch to the smooth brush. */
-    brush = BKE_paint_toolslots_brush_get(paint, SCULPT_TOOL_SMOOTH);
-    if (brush) {
-      BKE_paint_brush_set(paint, brush);
-      cache->saved_smooth_size = BKE_brush_size_get(scene, brush);
-      BKE_brush_size_set(scene, brush, cur_brush_size);
-      BKE_curvemapping_init(brush->curve);
-    }
+  /* Switch to the smooth brush if possible. */
+  Brush *smooth_brush = BKE_paint_toolslots_brush_get(paint, SCULPT_TOOL_SMOOTH);
+  if (!smooth_brush) {
+    printf("WARNING: Switching to the smooth brush not possible, corresponding brush not found\n");
+    return;
   }
+
+  int cur_brush_size = BKE_brush_size_get(scene, cur_brush);
+
+  STRNCPY(cache->saved_active_brush_name, cur_brush->id.name + 2);
+
+  BKE_paint_brush_set(paint, smooth_brush);
+  cache->saved_smooth_size = BKE_brush_size_get(scene, smooth_brush);
+  BKE_brush_size_set(scene, smooth_brush, cur_brush_size);
+  BKE_curvemapping_init(smooth_brush->curve);
 }
 
 static void smooth_brush_toggle_off(const bContext *C, Paint *paint, StrokeCache *cache)
@@ -4392,13 +4395,20 @@ static void smooth_brush_toggle_off(const bContext *C, Paint *paint, StrokeCache
   {
     /* Do nothing. */
   }
-  else {
-    /* Try to switch back to the saved/previous brush. */
-    BKE_brush_size_set(scene, brush, cache->saved_smooth_size);
-    brush = (Brush *)BKE_libblock_find_name(bmain, ID_BR, cache->saved_active_brush_name);
-    if (brush) {
-      BKE_paint_brush_set(paint, brush);
-    }
+
+  /* Note: used for both vertexpaint and weightpaint, VPAINT_TOOL_BLUR & WPAINT_TOOL_BLUR are the
+   * same, see comments for eBrushVertexPaintTool & eBrushWeightPaintTool. */
+  /* If the smooth brush is missing, brush was not switched/affected in smooth_brush_toggle_on().
+   */
+  if (!BKE_paint_toolslots_brush_get(paint, SCULPT_TOOL_SMOOTH)) {
+    return;
+  }
+
+  BKE_brush_size_set(scene, brush, cache->saved_smooth_size);
+
+  brush = (Brush *)BKE_libblock_find_name(bmain, ID_BR, cache->saved_active_brush_name);
+  if (brush) {
+    BKE_paint_brush_set(paint, brush);
   }
 }