Examples/Advanced/DeferredShading/DSSpotLight.fp.glsl

   1 #version 120
   2
   3 #extension GL_ARB_texture_rectangle : require
   4 #extension GL_ARB_texture_rectangle : enable
   5
   6 // compute spot light INDEX for fragment at POS with normal NORM
   7 // and diffuse material color MDIFF
   8 vec4 computeSpotLight(int index, vec3 pos, vec3 norm, vec4 mDiff)
   9 {
  10     vec4  color      = vec4(0., 0., 0., 0.);
  11
  12     vec3  lightDirUN = gl_LightSource[index].position.xyz - pos;
  13     vec3  lightDir   = normalize(lightDirUN);
  14     float spotEffect = dot(-lightDir, gl_LightSource[index].spotDirection);
  15
  16     if(spotEffect > gl_LightSource[index].spotCosCutoff)
  17     {
  18         float NdotL = max(dot(lightDir, norm), 0.);
  19
  20         if(NdotL > 0.)
  21         {
  22             float lightDist = length(lightDirUN);
  23             float att       = dot(vec3(gl_LightSource[index].constantAttenuation,
  24                                        gl_LightSource[index].linearAttenuation,
  25                                        gl_LightSource[index].quadraticAttenuation),
  26                                   vec3(1., lightDist, lightDist * lightDist)       );
  27             spotEffect = pow(spotEffect, gl_LightSource[index].spotExponent);
  28             att        = spotEffect / att;
  29
  30             color = att * NdotL * mDiff * gl_LightSource[index].diffuse;
  31         }
  32     }
  33
  34     return color;
  35 }
  36
  37 // DS input buffers
  38 uniform sampler2DRect     texBufPos;
  39 uniform sampler2DRect     texBufNorm;
  40 uniform sampler2DRect     texBufDiff;
  41 uniform vec2              vpOffset;
  42
  43 // DS pass
  44 void main(void)
  45 {
  46     vec2  lookup = gl_FragCoord.xy - vpOffset;
  47     vec3  norm   = texture2DRect(texBufNorm, lookup).xyz;
  48
  49     if(dot(norm, norm) < 0.95)
  50     {
  51         discard;
  52     }
  53     else
  54     {
  55         vec4  posAmb = texture2DRect(texBufPos,  lookup);
  56         vec3  pos    = posAmb.xyz;
  57         float amb    = posAmb.w;
  58         vec4  mDiff  = texture2DRect(texBufDiff, lookup);
  59
  60         gl_FragColor = computeSpotLight(0, pos, norm, mDiff);
  61     }
  62 }