Cycles / Fresnel Node:

* Add a "Normal" Input to the Fresnel node.
* Fix for the Fresnel GLSL code (normalize the Incoming vector).

Patch #37384 by Philipp Oeser (lichtwerk) , thanks! 

2 files changed, 6 insertions, 3 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 633112095a7..78664f3b539 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -2131,7 +2131,7 @@ void node_add_shader(vec4 shader1, vec4 shader2, out vec4 shader)
 void node_fresnel(float ior, vec3 N, vec3 I, out float result)
 {
 	float eta = max(ior, 0.00001);
-	result = fresnel_dielectric(I, N, (gl_FrontFacing)? eta: 1.0/eta);
+	result = fresnel_dielectric(normalize(I), N, (gl_FrontFacing)? eta: 1.0/eta);
 }
 
 /* gamma */
diff --git a/source/blender/nodes/shader/nodes/node_shader_fresnel.c b/source/blender/nodes/shader/nodes/node_shader_fresnel.c
index 1e5c10968a5..c22b0f41695 100644
--- a/source/blender/nodes/shader/nodes/node_shader_fresnel.c
+++ b/source/blender/nodes/shader/nodes/node_shader_fresnel.c
@@ -30,6 +30,7 @@
 /* **************** Fresnel ******************** */
 static bNodeSocketTemplate sh_node_fresnel_in[] = {
 	{	SOCK_FLOAT, 1, N_("IOR"),	1.45f, 0.0f, 0.0f, 0.0f, 1.0f, 1000.0f},
+	{	SOCK_VECTOR, 1, N_("Normal"),	0.0f, 0.0f, 0.0f, 1.0f, -1.0f, 1.0f, PROP_NONE, SOCK_HIDE_VALUE},
 	{	-1, 0, ""	}
 };
 
@@ -40,8 +41,10 @@ static bNodeSocketTemplate sh_node_fresnel_out[] = {
 
 static int node_shader_gpu_fresnel(GPUMaterial *mat, bNode *UNUSED(node), bNodeExecData *UNUSED(execdata), GPUNodeStack *in, GPUNodeStack *out)
 {
-	/* todo: is incoming vector normalized? */
-	return GPU_stack_link(mat, "node_fresnel", in, out, GPU_builtin(GPU_VIEW_NORMAL), GPU_builtin(GPU_VIEW_POSITION));
+	if (!in[1].link)
+		in[1].link = GPU_builtin(GPU_VIEW_NORMAL);
+	
+	return GPU_stack_link(mat, "node_fresnel", in, out, GPU_builtin(GPU_VIEW_POSITION));
 }
 
 /* node type definition */