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// Copyright (c) 2008 the OpenTK Team. See license.txt for legal bla
// custom vertex attribute
attribute vec3 AttributeTangent;
// world uniforms
uniform vec3 Light_Position;
uniform vec3 Camera_Position;
// MUST be written to for FS
varying vec3 VaryingLightVector;
varying vec3 VaryingEyeVector;
void main()
{
gl_Position = ftransform();
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
vec3 nor = normalize( gl_NormalMatrix * gl_Normal );
vec3 tan = normalize( gl_NormalMatrix * AttributeTangent );
vec3 bi = cross(nor, tan);
// need positions in tangent space
vec3 vertex = vec3( gl_ModelViewMatrix * gl_Vertex );
vec3 temp = Light_Position - vertex;
VaryingLightVector.x = dot(temp, tan); // optimization, calculate dot products rather than building TBN matrix
VaryingLightVector.y = dot(temp, bi);
VaryingLightVector.z = dot(temp, nor);
temp = Camera_Position - vertex;
VaryingEyeVector.x = dot(temp, tan);
VaryingEyeVector.y = dot(temp, bi);
VaryingEyeVector.z = dot(temp, nor);
}
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