From 00bd631c7ccef79462f2904ecfb751d7b34ef91e Mon Sep 17 00:00:00 2001
From: Joseph Eagar <joeedh@gmail.com>
Date: Thu, 7 Oct 2021 02:27:09 -0700
Subject: [PATCH] Fix mask expand not properly supporting both inverse and keep
 mask modes being on at the same time.

---
 source/blender/editors/sculpt_paint/sculpt_expand.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/source/blender/editors/sculpt_paint/sculpt_expand.c b/source/blender/editors/sculpt_paint/sculpt_expand.c
index 40874375772..34da7daed65 100644
--- a/source/blender/editors/sculpt_paint/sculpt_expand.c
+++ b/source/blender/editors/sculpt_paint/sculpt_expand.c
@@ -1243,7 +1243,12 @@ static void sculpt_expand_mask_update_task_cb(void *__restrict userdata,
     }
 
     if (expand_cache->preserve) {
-      new_mask = max_ff(new_mask, expand_cache->original_mask[vd.index]);
+      if (expand_cache->invert) {
+        new_mask = min_ff(new_mask, expand_cache->original_mask[vd.index]);
+      }
+      else {
+        new_mask = max_ff(new_mask, expand_cache->original_mask[vd.index]);
+      }
     }
 
     if (new_mask == initial_mask) {