///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
// 
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///////////////////////////////////////////////////////////////////////////

//
// exrdisplay pipeline
//
// Simon Green <SGreen@nvidia.com>
// Drew Hess <dhess@ilm.com>
//

half3 knee (half3 x, half f)
{
    return log (x * f + 1) / f;
}

fragout main(vf30 In,
	     uniform texobjRECT image,
             uniform float3 defog,
             uniform float exposure,
             uniform float gamma = 1.0/2.2,
	     uniform half3 zerovec = {0,0,0},
	     uniform half grayTarget,
	     uniform half kneeLow,
	     uniform half kneeF
             )
{
    fragout Out;

    half3 c = h3texRECT(image, In.TEX0.xy);

    c = max(zerovec, c - defog);

    c *= exposure;

    // knee

    c = (c > kneeLow) ? kneeLow + knee (c - kneeLow, kneeF) : c;

    // gamma correction
    // could use texture lookups for this

    c = pow(c, gamma);

    // scale middle gray to the target framebuffer value

    c *= grayTarget;

    Out.col.xyz = c;

    return Out;
}