title: Help with Pixel Shader effect for brightness and contrast
body: <p>What is a simple pixel shader script effect to apply brightness and contrast?</p>
  
  <p>I found this one, but it doesn't seem to be correct:</p>
  
  <pre><code>sampler2D input : register(s0);
  float brightness : register(c0);
  float contrast : register(c1);
  
  float4 main(float2 uv : TEXCOORD) : COLOR
  {
      float4 color = tex2D(input, uv); 
      float4 result = color;
      result = color + brightness;
      result = result * (1.0+contrast)/1.0;
  
      return result;
  }
  </code></pre>
  
  <p>thanks!</p>