[Bf-blender-cvs] [c8e87edccbd] blender2.8: Eevee: Render: Fix Ao pass background contamination.

[Clément Foucault]

Commit: c8e87edccbd0f7dfba33db8f792e9b1182e41de4
Author: Clément Foucault
Date:   Sat Feb 3 03:17:22 2018 +0100
Branches: blender2.8
https://developer.blender.org/rBc8e87edccbd0f7dfba33db8f792e9b1182e41de4

Eevee: Render: Fix Ao pass background contamination.

It was poluted by the additive blend mode.

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

M	source/blender/draw/engines/eevee/shaders/effect_gtao_frag.glsl

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

diff --git a/source/blender/draw/engines/eevee/shaders/effect_gtao_frag.glsl b/source/blender/draw/engines/eevee/shaders/effect_gtao_frag.glsl
index 32edf709d88..b7bcf5c8a8b 100644
--- a/source/blender/draw/engines/eevee/shaders/effect_gtao_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/effect_gtao_frag.glsl
@@ -28,7 +28,8 @@ void main()
 
 	gtao_deferred(normal, viewPosition, noise, depth, visibility, bent_normal);
 
-	FragColor = vec4(visibility);
+	/* Handle Background case. Prevent artifact due to uncleared Horizon Render Target. */
+	FragColor = vec4((depth == 1.0) ? 0.0 : visibility);
 }
 
 #else