[Bf-blender-cvs] [795bddf2bda] master: Fix T55620 Artifacts with SSR and planar reflection

[Clément Foucault]

Commit: 795bddf2bda4708996228d368dd410203b737b63
Author: Clément Foucault
Date:   Fri Mar 15 23:31:41 2019 +0100
Branches: master
https://developer.blender.org/rB795bddf2bda4708996228d368dd410203b737b63

Fix T55620 Artifacts with SSR and planar reflection

Was caused by 0 pixel extent rays which did not trace at all. Bumping the
threshold for degenerate rays fixes it.

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

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

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

diff --git a/source/blender/draw/engines/eevee/shaders/raytrace_lib.glsl b/source/blender/draw/engines/eevee/shaders/raytrace_lib.glsl
index d5a51f89e81..80389402129 100644
--- a/source/blender/draw/engines/eevee/shaders/raytrace_lib.glsl
+++ b/source/blender/draw/engines/eevee/shaders/raytrace_lib.glsl
@@ -91,7 +91,7 @@ void prepare_raycast(
 
 	/* If the line is degenerate, make it cover at least one pixel
 	 * to not have to handle zero-pixel extent as a special case later */
-	ss_step.xy += vec2((dot(ss_step.xy, ss_step.xy) < 0.000001) ? 0.001 : 0.0);
+	ss_step.xy += vec2((dot(ss_step.xy, ss_step.xy) < 0.000003) ? 0.001 : 0.0);
 
 	/* Make ss_step cover one pixel. */
 	ss_step /= max(abs(ss_step.x), abs(ss_step.y));