// Uncharted 2 tone map
// see: http://filmicworlds.com/blog/filmic-tonemapping-operators/
vec3 toneMapUncharted2Impl(vec3 color)
{
    const float A = 0.15;
    const float B = 0.50;
    const float C = 0.10;
    const float D = 0.20;
    const float E = 0.02;
    const float F = 0.30;
    return ((color*(A*color+C*B)+D*E)/(color*(A*color+B)+D*F))-E/F;
}

vec3 ToneMapping(vec3 color)
{
    const float W = 11.2;
    color = toneMapUncharted2Impl(color * 2.0);
    vec3 whiteScale = 1.0 / toneMapUncharted2Impl(vec3(W));
    return linearTosRGB(color * whiteScale);
}