source: GTP/trunk/App/Demos/Illum/IBRBillboardCloudTrees/OGRE/IBRTreesOGRE/media/general/indirectTexturingDefault_glsl_FP20.shd @ 1493

uniform sampler2D indirectTexture;
uniform sampler2D sourceTexture;
uniform float epsilonX;
uniform float epsilonY;
uniform float sourceTextureSize;
uniform float numSamples;
uniform float sqrtNumSamples;

void main(void)
{
   vec4 ocolor = vec4(0.0, 0.0, 0.0, 0.0);      
   vec2 epsilon = vec2(epsilonX, epsilonY);
   vec2 texCoord = gl_TexCoord[0].xy;
   vec2 subTexCoord = gl_TexCoord[1].xy;   
   vec4 value = texture2D(indirectTexture, subTexCoord).xyzw;
   vec2 coords = vec2(0.0, 1.0) - abs(texCoord - ( value.xy - epsilon ) );

   if (value.z != 0.0) 
   {       
        vec2 newcoord = (vec2(1.0, 1.0) - value.zw) + ((coords * sourceTextureSize) / sqrtNumSamples);
        ocolor = vec4(texture2D(sourceTexture, newcoord).xyzw);
   }
   gl_FragColor = ocolor; 
}