source: GTP/trunk/App/Demos/Illum/IBRBillboardCloudTrees/OGRE/IBRTreesOGRE/media/oldgeneral/tree_leaves_fp.txt @ 1493

float backProjectionCut: register(c2);
float Ka: register(c3);
float Kd: register(c4);
float Ks: register(c5);
float4 modelColor: register(c0);
float shadowBias: register(c1);
sampler ImpostorMap;
sampler RotatedLeaf;
sampler ShadowMap;
sampler SpotLight;

float4 main(float3 normal: TEXCOORD0, float3 lightVec: TEXCOORD1, float3 viewVec: TEXCOORD2, float4 shadowCrd: TEXCOORD3, float4 texCoord: TEXCOORD4, float4 texCoordNormalized: TEXCOORD5) : COLOR {
   normal = normalize(normal);
   // Radial distance
   float depth = length(lightVec);
   // Normalizes light vector
   lightVec /= depth;

   // Standard lighting
   float diffuse = saturate(dot(lightVec, normal));
   float specular = pow(saturate(dot(reflect(-normalize(viewVec), normal), lightVec)), 16);

   // The depth of the fragment closest to the light
   float shadowMap = tex2Dproj(ShadowMap, shadowCrd);
   // A spot image of the spotlight
   float spotLight = tex2Dproj(SpotLight, shadowCrd);
   // If the depth is larger than the stored depth, this fragment
   // is not the closest to the light, that is we are in shadow.
   // Otherwise, we're lit. Add a bias to avoid precision issues
   float shadow;
   shadow = (depth < shadowMap + shadowBias);

   // Cut back-projection, that is, make sure we don't lit
   // anything behind the light. Theoretically, you should just
   // cut at w = 0, but in practice you'll have to cut at a
   // fairly high positive number to avoid precision issue when
   // coordinates approaches zero. 
   shadow *= (shadowCrd.w > backProjectionCut);
   // Modulate with spotlight image
   shadow *= spotLight;

   // Shadow any light contribution except ambient
   //return Ka * modelColor + (Kd * diffuse * modelColor + Ks * specular) * shadow;
   float4 ocolor;
   //ocolor = Ka * modelColor + (Kd * diffuse * modelColor + Ks * specular) * shadow;
   float4 tempcolor = tex2D(ImpostorMap,texCoord);
   float3 green = float3(0.0,0.8,0.0);
   //ocolor = float4(Ka * tempcolor.xyz + (Kd * diffuse * tempcolor.xyz + Ks * specular) * shadow,tempcolor.z);
   ocolor = float4(Ka * green + (Kd * diffuse * green + Ks * specular) * shadow,tempcolor.z);
   
   float scale_factor = 48.0;
   float tex_atlas_size = 256;
   float4 vis = tex2D(ImpostorMap, texCoord); 
   float index = vis.z;
   if (vis.x >= 0.0)
   {
      float2 leafuv = (texCoordNormalized - vis.xy) * (tex_atlas_size/scale_factor);      
      float divInt = floor(index/4.0);
      float modInt = (index - (4.0 * divInt));
      float col = divInt / 4.0;
      float row = modInt / 4.0;
      // Using the leaf atlas...
      float2 leafuvr = float2(leafuv.x + row,leafuv.y + col); 
      tempcolor = tex2D(RotatedLeaf, leafuvr);
   }   
   ocolor = tempcolor;
      
   return ocolor; 
   //return ocolor = tempcolor; 
}