[Bf-blender-cvs] [4e28d88ece2] blender2.8: Fix T51724: Blender 2.80 EEVEE, Cycles, Clay Black Wall Graphical Glitch

[Sergey Sharybin]

Commit: 4e28d88ece20fabd773a0a2e7b3423227358b7c7
Author: Sergey Sharybin
Date:   Fri Jul 21 12:08:25 2017 +0200
Branches: blender2.8
https://developer.blender.org/rB4e28d88ece20fabd773a0a2e7b3423227358b7c7

Fix T51724: Blender 2.80 EEVEE, Cycles, Clay Black Wall Graphical Glitch

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M	source/blender/draw/modes/shaders/object_grid_frag.glsl

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diff --git a/source/blender/draw/modes/shaders/object_grid_frag.glsl b/source/blender/draw/modes/shaders/object_grid_frag.glsl
index 0196b1a6f98..61bd4d58a4a 100644
--- a/source/blender/draw/modes/shaders/object_grid_frag.glsl
+++ b/source/blender/draw/modes/shaders/object_grid_frag.glsl
@@ -75,7 +75,11 @@ vec3 get_floor_pos(vec2 uv, out vec3 wPos)
 		camera_vec = normalize(eye);
 	}
 
-	float p = -dot(planeNormal, camera_pos) / dot(planeNormal, camera_vec);
+	float plane_normal_dot_camera_vec = dot(planeNormal, camera_vec);
+	float p = -dot(planeNormal, camera_pos);
+	if (plane_normal_dot_camera_vec != 0) {
+		p /= plane_normal_dot_camera_vec;
+	}
 	vec3 plane = camera_pos + camera_vec * p;
 
 	/* fix residual imprecision */