Fix T91680: viewport selection broken in macOS x86 build with Xcode 13

There is an apparent compiler bug here, tweak the code to avoid it. This did
not affect official builds as we were still using Xcode 12.

1 files changed, 21 insertions, 13 deletions

diff --git a/source/blender/editors/space_view3d/view3d_view.c b/source/blender/editors/space_view3d/view3d_view.c
index b49d388019e..157c3682ee0 100644
--- a/source/blender/editors/space_view3d/view3d_view.c
+++ b/source/blender/editors/space_view3d/view3d_view.c
@@ -740,12 +740,12 @@ void view3d_winmatrix_set(Depsgraph *depsgraph,
                           const rcti *rect)
 {
   RegionView3D *rv3d = region->regiondata;
-  rctf viewplane;
+  rctf full_viewplane;
   float clipsta, clipend;
   bool is_ortho;
 
   is_ortho = ED_view3d_viewplane_get(
-      depsgraph, v3d, rv3d, region->winx, region->winy, &viewplane, &clipsta, &clipend, NULL);
+      depsgraph, v3d, rv3d, region->winx, region->winy, &full_viewplane, &clipsta, &clipend, NULL);
   rv3d->is_persp = !is_ortho;
 
 #if 0
@@ -753,21 +753,29 @@ void view3d_winmatrix_set(Depsgraph *depsgraph,
          __func__,
          winx,
          winy,
-         viewplane.xmin,
-         viewplane.ymin,
-         viewplane.xmax,
-         viewplane.ymax,
+         full_viewplane.xmin,
+         full_viewplane.ymin,
+         full_viewplane.xmax,
+         full_viewplane.ymax,
          clipsta,
          clipend);
 #endif
 
-  if (rect) { /* picking */
-    rctf r;
-    r.xmin = viewplane.xmin + (BLI_rctf_size_x(&viewplane) * (rect->xmin / (float)region->winx));
-    r.ymin = viewplane.ymin + (BLI_rctf_size_y(&viewplane) * (rect->ymin / (float)region->winy));
-    r.xmax = viewplane.xmin + (BLI_rctf_size_x(&viewplane) * (rect->xmax / (float)region->winx));
-    r.ymax = viewplane.ymin + (BLI_rctf_size_y(&viewplane) * (rect->ymax / (float)region->winy));
-    viewplane = r;
+  /* Note the code here was tweaked to avoid an apparent compiler bug in clang 13 (see T91680). */
+  rctf viewplane;
+  if (rect) {
+    /* Smaller viewplane subset for selection picking. */
+    viewplane.xmin = full_viewplane.xmin +
+                     (BLI_rctf_size_x(&full_viewplane) * (rect->xmin / (float)region->winx));
+    viewplane.ymin = full_viewplane.ymin +
+                     (BLI_rctf_size_y(&full_viewplane) * (rect->ymin / (float)region->winy));
+    viewplane.xmax = full_viewplane.xmin +
+                     (BLI_rctf_size_x(&full_viewplane) * (rect->xmax / (float)region->winx));
+    viewplane.ymax = full_viewplane.ymin +
+                     (BLI_rctf_size_y(&full_viewplane) * (rect->ymax / (float)region->winy));
+  }
+  else {
+    viewplane = full_viewplane;
   }
 
   if (is_ortho) {