Modifiers: Vertex Weight Modifiers add invert vgroup option

Adds the invert vgroup mask option to the Vertex Weight modifiers.

These 3 modifiers share the same functions so they needed to be modified at the same time. They are all setup the same with the invert vgroup option being added. I had to add a flag to the Mix modifier but the others I use the existing flags.

Differential Revision: https://developer.blender.org/D6819

1 files changed, 5 insertions, 2 deletions

diff --git a/source/blender/modifiers/intern/MOD_weightvg_util.c b/source/blender/modifiers/intern/MOD_weightvg_util.c
index 4ff07b21ef4..c63065eec40 100644
--- a/source/blender/modifiers/intern/MOD_weightvg_util.c
+++ b/source/blender/modifiers/intern/MOD_weightvg_util.c
@@ -130,7 +130,8 @@ void weightvg_do_mask(const ModifierEvalContext *ctx,
                       const int tex_use_channel,
                       const int tex_mapping,
                       Object *tex_map_object,
-                      const char *tex_uvlayer_name)
+                      const char *tex_uvlayer_name,
+                      const bool invert_vgroup_mask)
 {
   int ref_didx;
   int i;
@@ -230,7 +231,9 @@ void weightvg_do_mask(const ModifierEvalContext *ctx,
     /* For each weight (vertex), make the mix between org and new weights. */
     for (i = 0; i < num; i++) {
       int idx = indices ? indices[i] : i;
-      const float f = defvert_find_weight(&dvert[idx], ref_didx) * fact;
+      const float f = invert_vgroup_mask ?
+                          1.0f - defvert_find_weight(&dvert[idx], ref_didx) * fact :
+                          defvert_find_weight(&dvert[idx], ref_didx) * fact;
       org_w[i] = (new_w[i] * f) + (org_w[i] * (1.0f - f));
       /* If that vertex is not in ref vgroup, assume null factor, and hence do nothing! */
     }