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//uniform float far;
//uniform float near;
uniform float width;
uniform vec3 meshCenter;
/*uniform mat4 modelViewMX;
uniform mat4 prjMX;
*/
void main(void)
{
//vec3 lightPosition = vec3(-1.0,0.0,0.0);
vec4 lightPosition = gl_ModelViewMatrix * gl_LightSource[0].position;
//Reproduce GL_LookAt behaviour
//create ortonormal basis for lightspace
vec3 newZ = normalize(lightPosition .xyz);
vec3 newX = normalize(cross(newZ, vec3(0.0, 0.80001, 0.0)));
vec3 newY = normalize(cross(newX, newZ));
mat4 toLightSpaceRot = mat4(
newX.x, newY.x, newZ.x, 0.0,
newX.y, newY.y, newZ.y, 0.0,
newX.z, newY.z, newZ.z, 0.0,
0.0, 0.0, 0.0, 1.0
);
//Perform parallel Ortographic projection
float nearP = - (width / 2.0);//meshCenter.z - (width / 2.0); //distance of Front clipping plane from VRP measured along VPN (a.k.a. lightDir)
float farP = (width / 2.0);//meshCenter.z + (width / 2.0);//distance of Back clipping plane from VRP measured along VPN (a.k.a. lightDir)
float leftP = meshCenter.x - width/2.0;
float rightP = meshCenter.x + width/2.0;
float bottomP = meshCenter.y - width/2.0;
float topP = meshCenter.y + width/2.0;
mat4 parallelViewProject = mat4(
2.0/(rightP-leftP), 0.0, 0.0, 0.0,
0.0, 2.0/(topP-bottomP), 0.0, 0.0,
0.0, 0.0, 2.0/(farP - nearP), 0.0,
-(rightP + leftP)/(rightP - leftP), -(topP + bottomP)/(topP-bottomP), -(farP + nearP)/(farP - nearP), 1.0
);
gl_Position = parallelViewProject
* toLightSpaceRot
* gl_Vertex;
}
/*void main(){
gl_Position = ftransform();
}*/
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