[Bf-blender-cvs] [aa2e978bd8b] master: Fix T79557 EEVEE: Normalize in vector math node is not null vector safe

[Clément Foucault]

Commit: aa2e978bd8b47dbc06826698b07d850cdd499568
Author: Clément Foucault
Date:   Fri Sep 18 23:42:43 2020 +0200
Branches: master
https://developer.blender.org/rBaa2e978bd8b47dbc06826698b07d850cdd499568

Fix T79557 EEVEE: Normalize in vector math node is not null vector safe

This add basic null safe handling for this operation.

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

M	source/blender/gpu/shaders/material/gpu_shader_material_vector_math.glsl

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

diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_vector_math.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_vector_math.glsl
index 256fdcafe3c..0b65fdb229a 100644
--- a/source/blender/gpu/shaders/material/gpu_shader_material_vector_math.glsl
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_vector_math.glsl
@@ -64,7 +64,12 @@ void vector_math_scale(vec3 a, vec3 b, vec3 c, float scale, out vec3 outVector,
 void vector_math_normalize(
     vec3 a, vec3 b, vec3 c, float scale, out vec3 outVector, out float outValue)
 {
-  outVector = normalize(a);
+  outVector = a;
+  /* Safe version of normalize(a). */
+  float lenSquared = dot(a, a);
+  if (lenSquared > 0.0) {
+    outVector *= inversesqrt(lenSquared);
+  }
 }
 
 void vector_math_snap(vec3 a, vec3 b, vec3 c, float scale, out vec3 outVector, out float outValue)