Decimate Modifier: Restore vertex group factor property in UI

This property was inadvertently removed from the modifier's panel and
it wasn't caught in time for the release of 2.90. Thanks to the user
"VermossomreV" for bringing this to my attention.

Differential Revision: https://developer.blender.org/D8790

1 files changed, 4 insertions, 0 deletions

diff --git a/source/blender/modifiers/intern/MOD_decimate.c b/source/blender/modifiers/intern/MOD_decimate.c
index 68c330452b3..72a868cc6a7 100644
--- a/source/blender/modifiers/intern/MOD_decimate.c
+++ b/source/blender/modifiers/intern/MOD_decimate.c
@@ -257,6 +257,10 @@ static void panel_draw(const bContext *UNUSED(C), Panel *panel)
     uiItemR(layout, ptr, "use_collapse_triangulate", 0, NULL, ICON_NONE);
 
     modifier_vgroup_ui(layout, ptr, &ob_ptr, "vertex_group", "invert_vertex_group", NULL);
+    sub = uiLayoutRow(layout, true);
+    bool has_vertex_group = RNA_string_length(ptr, "vertex_group") != 0;
+    uiLayoutSetActive(sub, has_vertex_group);
+    uiItemR(sub, ptr, "vertex_group_factor", 0, NULL, ICON_NONE);
   }
   else if (decimate_type == MOD_DECIM_MODE_UNSUBDIV) {
     uiItemR(layout, ptr, "iterations", 0, NULL, ICON_NONE);