[Bf-blender-cvs] [dd14145511c] blender2.8: EEVEE: Fix contact shadows on flat objects/backfaces.

[Clément Foucault]

Commit: dd14145511c7c0e9aae3606bafeb350d19502e8a
Author: Clément Foucault
Date:   Tue Apr 24 14:56:35 2018 +0200
Branches: blender2.8
https://developer.blender.org/rBdd14145511c7c0e9aae3606bafeb350d19502e8a

EEVEE: Fix contact shadows on flat objects/backfaces.

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

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diff --git a/source/blender/draw/engines/eevee/shaders/lamps_lib.glsl b/source/blender/draw/engines/eevee/shaders/lamps_lib.glsl
index ae7cae9c4bb..2e7c78e287d 100644
--- a/source/blender/draw/engines/eevee/shaders/lamps_lib.glsl
+++ b/source/blender/draw/engines/eevee/shaders/lamps_lib.glsl
@@ -211,7 +211,7 @@ float light_visibility(LightData ld, vec3 W,
 			vec3 ray_dir = L.xyz + T * rand.z + B * rand.w;
 			ray_dir = transform_direction(ViewMatrix, ray_dir);
 			ray_dir = normalize(ray_dir);
-			vec3 ray_origin = viewPosition + viewNormal * data.sh_contact_offset;
+			vec3 ray_origin = viewPosition + viewNormal * (gl_FrontFacing ? data.sh_contact_offset : -data.sh_contact_offset);
 			vec3 hit_pos = raycast(-1, ray_origin, ray_dir * trace_distance, data.sh_contact_thickness, rand.x,
 			                       0.75, 0.01, false);