sampler s0 : register(s0);

float4 main(float2 tex : TEXCOORD0) : COLOR
{

       float exposure = float(15);
       float luminance = float(-0.5);

       float4 input = tex2D(s0,tex);
       float4 output = float4(1,1,1,1);

       //calculate exposure
       input *= exposure;

       //convert to YCbCr
       float Y = float(0.299*input.r + 0.587 * input.g + 0.114 * input.b);
       float Cb = float(-0.1687 * input.r + -0.3313 * input.g + 0.5 * input.b + 0.5);
       float Cr = float(0.5 * input.r - 0.4187 * input.g - 0.0813 * input.b + 0.5);

       //calculate luminance
       Y = Y+ luminance;


       //convert back to RGB
       float R = float(Y + 1.402 * (Cr - 0.5));
       float G = float(Y - 0.34414 * (Cb - 0.5) - 0.71414 * (Cr - 0.5));
       float B = float(Y + 1.772 * (Cb - 0.5));



       //DRAW Original
       if (tex.y<0.5){
               output = tex2D(s0,tex);


       //DRAW Exposure + Luminance
       }else {
               output = float4(R,G,B,1);
       }



       return output;
}

sampler s0 : register(s0);
 
float4 main(float2 tex : TEXCOORD0) : COLOR
{
 
       float exposure = float(15);
       float luminance = float(-0.5);
 
       float4 input = tex2D(s0,tex);
       float4 output = float4(1,1,1,1);
 
       //calculate exposure
       input *= exposure;
 
       //convert to YCbCr
       float Y = float(0.299*input.r + 0.587 * input.g + 0.114 * input.b);
       float Cb = float(-0.1687 * input.r + -0.3313 * input.g + 0.5 * input.b + 0.5);
       float Cr = float(0.5 * input.r - 0.4187 * input.g - 0.0813 * input.b + 0.5);
 
       //calculate luminance
       Y = Y+ luminance;
 
 
       //convert back to RGB
       float R = float(Y + 1.402 * (Cr - 0.5));
       float G = float(Y - 0.34414 * (Cb - 0.5) - 0.71414 * (Cr - 0.5));
       float B = float(Y + 1.772 * (Cb - 0.5));
 
 
 
       //DRAW Original
       if (tex.y<0.5){
               output = tex2D(s0,tex);
 
 
       //DRAW Exposure + Luminance
       }else {
               output = float4(R,G,B,1);
       }
 
 
 
       return output;
}