[Bf-blender-cvs] [59404853698] blender-v2.83-release: Fix T76168 Workbench: Shadows behind a culled backface are inverted

[Clément Foucault]

Commit: 59404853698d01892ee5c609755ffad7ee57c3b9
Author: Clément Foucault
Date:   Thu May 14 17:39:18 2020 +0200
Branches: blender-v2.83-release
https://developer.blender.org/rB59404853698d01892ee5c609755ffad7ee57c3b9

Fix T76168 Workbench: Shadows behind a culled backface are inverted

===================================================================

M	source/blender/draw/engines/workbench/workbench_shadow.c

===================================================================

diff --git a/source/blender/draw/engines/workbench/workbench_shadow.c b/source/blender/draw/engines/workbench/workbench_shadow.c
index efd0ad9134e..2cf5f3c4c13 100644
--- a/source/blender/draw/engines/workbench/workbench_shadow.c
+++ b/source/blender/draw/engines/workbench/workbench_shadow.c
@@ -333,6 +333,11 @@ void workbench_shadow_cache_populate(WORKBENCH_Data *data, Object *ob, const boo
       use_shadow_pass_technique = false;
     }
 
+    /* We cannot use Shadow Pass technique on non-manifold object (see T76168). */
+    if (use_shadow_pass_technique && !is_manifold && (wpd->cull_state != 0)) {
+      use_shadow_pass_technique = false;
+    }
+
     if (use_shadow_pass_technique) {
       grp = DRW_shgroup_create_sub(wpd->shadow_pass_grp[is_manifold]);
       DRW_shgroup_uniform_vec3(grp, "lightDirection", engine_object_data->shadow_dir, 1);