20 lines
915 B
HLSL
20 lines
915 B
HLSL
// Copyright (c) Le Loc Tai <leloctai.com> . All rights reserved. Do not redistribute.
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#include <UnityCG.cginc>
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// This need to be a macro since the type of tex can change :(
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#define SAMPLE_SCREEN_TEX(tex, uv) UNITY_SAMPLE_SCREENSPACE_TEXTURE(tex, UnityStereoTransformScreenSpaceTex(uv))
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// This piecewise approximation has a precision better than 0.5 / 255 in gamma space over the [0..255] range
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// i.e. abs(l2g_exact(g2l_approx(value)) - value) < 0.5 / 255
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// It is much more precise than GammaToLinearSpace but remains relatively cheap
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half3 UIGammaToLinearShim(half3 value)
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{
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half3 low = 0.0849710 * value - 0.000163029;
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half3 high = value * (value * (value * 0.265885 + 0.736584) - 0.00980184) + 0.00319697;
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// We should be 0.5 away from any actual gamma value stored in an 8 bit channel
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const half3 split = (half3)0.0725490; // Equals 18.5 / 255
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return (value < split) ? low : high;
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}
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