Fix T80603 Workbench: Inverted alpha when rendering

This was caused by a left over DRWPass->state modification
that made the subsequent samples redraw without Blending enabled.
This led to incorrect blending.

The fix is to use the new API for pass instancing.

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/draw/intern/draw_manager_data.c b/source/blender/draw/intern/draw_manager_data.c
index 81842f5d2ec..ca5d5170262 100644
--- a/source/blender/draw/intern/draw_manager_data.c
+++ b/source/blender/draw/intern/draw_manager_data.c
@@ -1962,6 +1962,8 @@ DRWPass *DRW_pass_create(const char *name, DRWState state)
   return pass;
 }
 
+/* Create an instance of the original pass that will execute the same drawcalls but with its own
+ * DRWState. */
 DRWPass *DRW_pass_create_instance(const char *name, DRWPass *original, DRWState state)
 {
   DRWPass *pass = DRW_pass_create(name, state);
@@ -1980,6 +1982,10 @@ void DRW_pass_link(DRWPass *first, DRWPass *second)
 
 bool DRW_pass_is_empty(DRWPass *pass)
 {
+  if (pass->original) {
+    return DRW_pass_is_empty(pass->original);
+  }
+
   LISTBASE_FOREACH (DRWShadingGroup *, shgroup, &pass->shgroups) {
     if (!DRW_shgroup_is_empty(shgroup)) {
       return false;