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#version 330 core
in EyeSpaceVertex {
vec3 position;
vec3 normal;
} fs_in;
out vec4 fragColor;
uniform struct LightInfo {
vec4 position;
vec3 intensity;
} light;
uniform struct LineInfo {
float width;
vec4 color;
} line;
uniform vec3 ka; // Ambient reflectivity
uniform vec3 kd; // Diffuse reflectivity
vec3 rimLightModel( const in vec3 pos, const in vec3 n )
{
// Calculate the vector from the light to the fragment
vec3 s = normalize( vec3( light.position ) - pos );
// Calculate the vector from the fragment to the eye position (the
// origin since this is in "eye" or "camera" space
vec3 v = normalize( -pos );
// Refleft the light beam using the normal at this fragment
vec3 r = reflect( -s, n );
// Calculate the diffuse component, which for rim lighting it 1 minus s dot n
// rather than s dot n as for standard diffuse lighting
float sDotN = dot( s, n );
vec3 diffuse = vec3( 1.0 - max( sDotN, 0.0 ) );
// Combine the ambient, diffuse and specular contributions
return light.intensity * ( ka + kd * diffuse );
}
void main()
{
vec3 n = gl_FrontFacing ? fs_in.normal : -fs_in.normal;
vec4 color = vec4( rimLightModel( fs_in.position, normalize( n ) ), 1.0 );
fragColor = color;
}
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