Fix T40478: wrong cycles fresnel with GLSL materials in the viewport.

diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 44119d4a9139495fb534fe641724234ce4e9d479..5c7872a8b3a40af70904ef07ba5e3472c3f634d4 100644 (file)
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -2197,8 +2197,11 @@ void node_add_shader(vec4 shader1, vec4 shader2, out vec4 shader)
 
 void node_fresnel(float ior, vec3 N, vec3 I, out float result)
 {
+       /* handle perspective/orthographic */
+       vec3 I_view = (gl_ProjectionMatrix[3][3] == 0.0)? normalize(I): vec3(0.0, 0.0, -1.0);
+
        float eta = max(ior, 0.00001);
-       result = fresnel_dielectric(normalize(I), N, (gl_FrontFacing)? eta: 1.0/eta);
+       result = fresnel_dielectric(I_view, N, (gl_FrontFacing)? eta: 1.0/eta);
 }
 
 /* layer_weight */
@@ -2248,10 +2251,14 @@ void node_geometry(vec3 I, vec3 N, mat4 toworld,
        out float backfacing)
 {
        position = (toworld*vec4(I, 1.0)).xyz;
-       normal = N;
+       normal = (toworld*vec4(N, 0.0)).xyz;
        tangent = vec3(0.0);
-       true_normal = N;
-       incoming = I;
+       true_normal = normal;
+
+       /* handle perspective/orthographic */
+       vec3 I_view = (gl_ProjectionMatrix[3][3] == 0.0)? normalize(I): vec3(0.0, 0.0, -1.0);
+       incoming = -(toworld*vec4(I_view, 0.0)).xyz;
+
        parametric = vec3(0.0);
        backfacing = (gl_FrontFacing)? 0.0: 1.0;
 }