Nodes: Add Refract and Faceforward functions to Vector Maths nodes

Cycles, Eevee, OSL, Geo, Attribute

Based on outdated refract patch D6619 by @cubic_sloth

`refract` and `faceforward` are standard functions in GLSL, OSL and Godot shader languages.
Adding these functions provides Blender shader artists access to these standard functions.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D10622

1 files changed, 12 insertions, 0 deletions

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 0b65fdb229a..60ed098beb3 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
@@ -138,3 +138,15 @@ void vector_math_tangent(
 {
   outVector = tan(a);
 }
+
+void vector_math_refract(
+    vec3 a, vec3 b, vec3 c, float scale, out vec3 outVector, out float outValue)
+{
+  outVector = refract(a, normalize(b), scale);
+}
+
+void vector_math_faceforward(
+    vec3 a, vec3 b, vec3 c, float scale, out vec3 outVector, out float outValue)
+{
+  outVector = faceforward(a, b, c);
+}