source: GTP/trunk/App/Demos/Illum/IBRBillboardCloudTrees/OGRE/IBRTreesOGRE/media/general/indirectTexturingLighting_hlsl_VP20.shd @ 1493

struct VS_OUTPUT {
   float4 Pos:       POSITION;
   float2 texCoord:  TEXCOORD0;
   float2 subTexCoord: TEXCOORD1;

   float diffuse: TEXCOORD2;
};


uniform float4x4 worldviewproj;
uniform float3 lightPosition; // object space
uniform float3 eyePosition;   // object space
uniform float4 shininess;

VS_OUTPUT main_vp(
      float4 position: POSITION,
      float3 normal: NORMAL,
      float2 subTexCoord: TEXCOORD0,
      float4 color: COLOR
      )
{
        VS_OUTPUT Out;

        Out.Pos = mul(worldviewproj, position);
        Out.subTexCoord = subTexCoord;
        Out.texCoord = color.xy;

        // Calculate vertex to eye vector
        float3 vertToEye = position - eyePosition;
        float aligned = dot(normal, vertToEye);

        // calculate light vector
        float3 N = normalize(normal);
        float3 L = normalize(lightPosition - position.xyz);

        // calculate light vector
        N = normalize(-normal);
        L = normalize(lightPosition - position.xyz);
        
        // Calculate diffuse component
        Out.diffuse = clamp(dot(N, L) , 0.0, 1.0) + clamp(-dot(N, L) , 0.0, 1.0);
        
        return Out;
}