48 lines
1.3 KiB
GLSL
48 lines
1.3 KiB
GLSL
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// Shader based on work by Fabien Sanglard
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// Released under the terms of CC-BY 3.0
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varying vec3 lightVec;
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varying vec3 halfVec;
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varying vec3 eyeVec;
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uniform vec3 lightdir;
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void main()
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{
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gl_TexCoord[0] = gl_MultiTexCoord0;
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// Building the matrix Eye Space -> Tangent Space
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vec3 n = normalize (gl_NormalMatrix * gl_Normal);
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// gl_MultiTexCoord1.xyz
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vec3 t = normalize (gl_NormalMatrix * vec3(1.0, 0.0, 0.0)); // tangent
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vec3 b = cross (n, t);
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vec3 vertexPosition = vec3(gl_ModelViewMatrix * gl_Vertex);
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// transform light and half angle vectors by tangent basis
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vec3 v;
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v.x = dot (lightdir, t);
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v.y = dot (lightdir, b);
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v.z = dot (lightdir, n);
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lightVec = normalize (v);
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vertexPosition = normalize(vertexPosition);
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eyeVec = normalize(-vertexPosition); // we are in Eye Coordinates, so EyePos is (0,0,0)
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// Normalize the halfVector to pass it to the fragment shader
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// No need to divide by two, the result is normalized anyway.
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// vec3 halfVector = normalize((vertexPosition + lightDir) / 2.0);
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vec3 halfVector = normalize(vertexPosition + lightdir);
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v.x = dot (halfVector, t);
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v.y = dot (halfVector, b);
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v.z = dot (halfVector, n);
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// No need to normalize, t,b,n and halfVector are normal vectors.
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//normalize (v);
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halfVec = v ;
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gl_Position = ftransform();
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}
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