Revert "Sculpt: Remove partial viewport updates from sculpt stroke code"

This reverts commit 394b48029c5335381f774f83524ad6ee5cb986da.

Leaving this here does not affect performance in any significant way and it may be useful in the future.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D6688

1 files changed, 18 insertions, 2 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index 00fb8abc06d..23521b8496c 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -7537,7 +7537,9 @@ static void sculpt_flush_update_step(bContext *C, SculptUpdateType update_flags)
     ED_region_tag_redraw(ar);
   }
   else {
-    /* Fast path where we just update the BVH nodes that changed. */
+    /* Fast path where we just update the BVH nodes that changed, and redraw
+     * only the part of the 3D viewport where changes happened. */
+    rcti r;
 
     if (update_flags & SCULPT_UPDATE_COORDS) {
       BKE_pbvh_update_bounds(ss->pbvh, PBVH_UpdateBB);
@@ -7547,7 +7549,21 @@ static void sculpt_flush_update_step(bContext *C, SculptUpdateType update_flags)
       sculpt_update_object_bounding_box(ob);
     }
 
-    ED_region_tag_redraw(ar);
+    if (sculpt_get_redraw_rect(ar, CTX_wm_region_view3d(C), ob, &r)) {
+      if (ss->cache) {
+        ss->cache->current_r = r;
+      }
+
+      /* previous is not set in the current cache else
+       * the partial rect will always grow */
+      sculpt_extend_redraw_rect_previous(ob, &r);
+
+      r.xmin += ar->winrct.xmin - 2;
+      r.xmax += ar->winrct.xmin + 2;
+      r.ymin += ar->winrct.ymin - 2;
+      r.ymax += ar->winrct.ymin + 2;
+      ED_region_tag_redraw_partial(ar, &r, true);
+    }
   }
 }