<shader>
  <uniform name="brightness" value="1.0"/>
  <uniform name="contrast" value="1.0"/>
  <![CDATA[
    #pragma vp_entryPoint applyBrightnessContrast
    #pragma vp_location fragment_coloring
    
    uniform float brightness;
    uniform float contrast;
    
    void applyBrightnessContrast(inout vec4 color) 
    {
        color.rgb = ((color.rgb - 0.5)*contrast + 0.5) * brightness;
        color.rgb = clamp(color.rgb, 0, 1);
    }
  ]]>
</shader>
