Freestyle: Add option for rendering Freestyle to a separate pass

This allows for more flexibility in Compositing compared to the
hardcoded alpha-over that is currently used.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D6829

1 files changed, 9 insertions, 1 deletions

diff --git a/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp b/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
index fdf9d4bac3d..0877107a240 100644
--- a/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
+++ b/source/blender/freestyle/intern/blender_interface/FRS_freestyle.cpp
@@ -549,7 +549,15 @@ void FRS_composite_result(Render *re, ViewLayer *view_layer, Render *freestyle_r
     }
     return;
   }
-  dest = RE_RenderLayerGetPass(rl, RE_PASSNAME_COMBINED, re->viewname);
+
+  if (view_layer->freestyle_config.flags & FREESTYLE_AS_RENDER_PASS) {
+    RE_create_render_pass(
+        re->result, RE_PASSNAME_FREESTYLE, 4, "RGBA", view_layer->name, re->viewname);
+    dest = RE_RenderLayerGetPass(rl, RE_PASSNAME_FREESTYLE, re->viewname);
+  }
+  else {
+    dest = RE_RenderLayerGetPass(rl, RE_PASSNAME_COMBINED, re->viewname);
+  }
   if (!dest) {
     if (G.debug & G_DEBUG_FREESTYLE) {
       cout << "No destination result image to composite to" << endl;