[Bf-blender-cvs] [091b4336772] blender-v2.91-release: Fix T77658 EEVEE: Reflection Plane partially missing reflections

[Clément Foucault]

Commit: 091b43367725f65d3c7f81400ec57624dfa70b3b
Author: Clément Foucault
Date:   Thu Oct 22 00:20:06 2020 +0200
Branches: blender-v2.91-release
https://developer.blender.org/rB091b43367725f65d3c7f81400ec57624dfa70b3b

Fix T77658 EEVEE: Reflection Plane partially missing reflections

The degenerate line workaround was ill defined.

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

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diff --git a/source/blender/draw/engines/eevee/shaders/raytrace_lib.glsl b/source/blender/draw/engines/eevee/shaders/raytrace_lib.glsl
index dbb5e660dab..db3497bd043 100644
--- a/source/blender/draw/engines/eevee/shaders/raytrace_lib.glsl
+++ b/source/blender/draw/engines/eevee/shaders/raytrace_lib.glsl
@@ -105,7 +105,9 @@ void prepare_raycast(vec3 ray_origin,
 
   /* 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) < 0.00001) ? 0.001 : 0.0);
+  if (dot(ss_step.xy, ss_step.xy) < 0.00001) {
+    ss_step.xy = vec2(0.0, 0.0001);
+  }
 
   /* Make ss_step cover one pixel. */
   ss_step /= max(abs(ss_step.x), abs(ss_step.y));