DRW: New Select Debug Engine

This is a simple engine used only to debug the texture of select ids.

It is only used when the `WITH_DRAW_DEBUG` option is enabled and the
debug value is 31.

Reviewed By: fclem

Differential Revision: https://developer.blender.org/D5490

1 files changed, 9 insertions, 0 deletions

diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index 11e2856147f..027ab8ce32b 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -1281,6 +1281,12 @@ static void drw_engines_enable(ViewLayer *UNUSED(view_layer),
     use_drw_engine(&draw_engine_gpencil_type);
   }
   drw_engines_enable_overlays();
+
+#ifdef WITH_DRAW_DEBUG
+  if (G.debug_value == 31) {
+    use_drw_engine(&draw_engine_debug_select_type);
+  }
+#endif
 }
 
 static void drw_engines_disable(void)
@@ -2940,6 +2946,9 @@ void DRW_engines_register(void)
   DRW_engine_register(&draw_engine_overlay_type);
   DRW_engine_register(&draw_engine_select_type);
   DRW_engine_register(&draw_engine_basic_type);
+#ifdef WITH_DRAW_DEBUG
+  DRW_engine_register(&draw_engine_debug_select_type);
+#endif
 
   DRW_engine_register(&draw_engine_image_type);
   DRW_engine_register(DRW_engine_viewport_external_type.draw_engine);