| #define FP highp |
| |
| // TODO: Replace with a struct |
| uniform FP vec3 kd; // Diffuse reflectivity |
| uniform FP vec3 ks; // Specular reflectivity |
| uniform FP vec3 kblue; // Cool color |
| uniform FP vec3 kyellow; // Warm color |
| uniform FP float alpha; // Fraction of diffuse added to kblue |
| uniform FP float beta; // Fraction of diffuse added to kyellow |
| uniform FP float shininess; // Specular shininess factor |
| |
| uniform FP vec3 eyePosition; |
| |
| varying FP vec3 worldPosition; |
| varying FP vec3 worldNormal; |
| |
| #pragma include light.inc.frag |
| |
| FP vec3 goochModel( const in FP vec3 pos, const in FP vec3 n ) |
| { |
| // Based upon the original Gooch lighting model paper at: |
| // http://www.cs.northwestern.edu/~ago820/SIG98/abstract.html |
| |
| // Calculate kcool and kwarm from equation (3) |
| FP vec3 kcool = clamp(kblue + alpha * kd, 0.0, 1.0); |
| FP vec3 kwarm = clamp(kyellow + beta * kd, 0.0, 1.0); |
| |
| // Calculate the vector from the light to the fragment |
| FP vec3 s = normalize( vec3( lights[0].position ) - pos ); |
| |
| // Calculate the cos theta factor mapped onto the range [0,1] |
| FP float sDotNFactor = ( 1.0 + dot( s, n ) ) / 2.0; |
| |
| // Calculate the tone by blending the kcool and kwarm contributions |
| // as per equation (2) |
| FP vec3 intensity = mix( kcool, kwarm, sDotNFactor ); |
| |
| // Calculate the vector from the fragment to the eye position |
| FP vec3 v = normalize( eyePosition - pos ); |
| |
| // Reflect the light beam using the normal at this fragment |
| FP vec3 r = reflect( -s, n ); |
| |
| // Calculate the specular component |
| FP float specular = 0.0; |
| if ( dot( s, n ) > 0.0 ) |
| specular = pow( max( dot( r, v ), 0.0 ), shininess ); |
| |
| // Sum the blended tone and specular highlight |
| return intensity + ks * specular; |
| } |
| |
| void main() |
| { |
| gl_FragColor = vec4( goochModel( worldPosition, normalize( worldNormal ) ), 1.0 ); |
| } |