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386 行
9.1 KiB
386 行
9.1 KiB
#ifndef UNITY_COLOR_INCLUDED
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#define UNITY_COLOR_INCLUDED
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//-----------------------------------------------------------------------------
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// Gamma space - Assume positive values
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//-----------------------------------------------------------------------------
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// Gamma20
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real Gamma20ToLinear(real c)
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{
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return c * c;
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}
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real3 Gamma20ToLinear(real3 c)
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{
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return c.rgb * c.rgb;
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}
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real4 Gamma20ToLinear(real4 c)
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{
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return real4(Gamma20ToLinear(c.rgb), c.a);
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}
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real LinearToGamma20(real c)
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{
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return sqrt(c);
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}
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real3 LinearToGamma20(real3 c)
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{
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return sqrt(c.rgb);
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}
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real4 LinearToGamma20(real4 c)
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{
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return real4(LinearToGamma20(c.rgb), c.a);
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}
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// Gamma22
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real Gamma22ToLinear(real c)
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{
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return PositivePow(c, 2.2);
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}
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real3 Gamma22ToLinear(real3 c)
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{
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return PositivePow(c.rgb, real3(2.2, 2.2, 2.2));
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}
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real4 Gamma22ToLinear(real4 c)
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{
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return real4(Gamma22ToLinear(c.rgb), c.a);
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}
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real LinearToGamma22(real c)
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{
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return PositivePow(c, 0.454545454545455);
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}
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real3 LinearToGamma22(real3 c)
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{
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return PositivePow(c.rgb, real3(0.454545454545455, 0.454545454545455, 0.454545454545455));
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}
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real4 LinearToGamma22(real4 c)
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{
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return real4(LinearToGamma22(c.rgb), c.a);
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}
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// sRGB
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real3 SRGBToLinear(real3 c)
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{
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real3 linearRGBLo = c / 12.92;
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real3 linearRGBHi = PositivePow((c + 0.055) / 1.055, real3(2.4, 2.4, 2.4));
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real3 linearRGB = (c <= 0.04045) ? linearRGBLo : linearRGBHi;
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return linearRGB;
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}
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real4 SRGBToLinear(real4 c)
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{
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return real4(SRGBToLinear(c.rgb), c.a);
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}
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real3 LinearToSRGB(real3 c)
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{
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real3 sRGBLo = c * 12.92;
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real3 sRGBHi = (PositivePow(c, real3(1.0/2.4, 1.0/2.4, 1.0/2.4)) * 1.055) - 0.055;
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real3 sRGB = (c <= 0.0031308) ? sRGBLo : sRGBHi;
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return sRGB;
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}
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real4 LinearToSRGB(real4 c)
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{
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return real4(LinearToSRGB(c.rgb), c.a);
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}
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// TODO: Seb - To verify and refit!
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// Ref: http://chilliant.blogspot.com.au/2012/08/srgb-approximations-for-hlsl.html?m=1
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real3 FastSRGBToLinear(real3 c)
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{
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return c * (c * (c * 0.305306011 + 0.682171111) + 0.012522878);
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}
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real4 FastSRGBToLinear(real4 c)
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{
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return real4(FastSRGBToLinear(c.rgb), c.a);
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}
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real3 FastLinearToSRGB(real3 c)
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{
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return saturate(1.055 * PositivePow(c, 0.416666667) - 0.055);
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}
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real4 FastLinearToSRGB(real4 c)
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{
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return real4(FastLinearToSRGB(c.rgb), c.a);
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}
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//-----------------------------------------------------------------------------
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// Color space
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//-----------------------------------------------------------------------------
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// Convert rgb to luminance
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// with rgb in linear space with sRGB primaries and D65 white point
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real Luminance(real3 linearRgb)
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{
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return dot(linearRgb, real3(0.2126729, 0.7151522, 0.0721750));
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}
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real Luminance(real4 linearRgba)
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{
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return Luminance(linearRgba.rgb);
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}
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// This function take a rgb color (best is to provide color in sRGB space)
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// and return a YCoCg color in [0..1] space for 8bit (An offset is apply in the function)
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// Ref: http://www.nvidia.com/object/real-time-ycocg-dxt-compression.html
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#define YCOCG_CHROMA_BIAS (128.0 / 255.0)
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real3 RGBToYCoCg(real3 rgb)
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{
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real3 YCoCg;
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YCoCg.x = dot(rgb, real3(0.25, 0.5, 0.25));
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YCoCg.y = dot(rgb, real3(0.5, 0.0, -0.5)) + YCOCG_CHROMA_BIAS;
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YCoCg.z = dot(rgb, real3(-0.25, 0.5, -0.25)) + YCOCG_CHROMA_BIAS;
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return YCoCg;
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}
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real3 YCoCgToRGB(real3 YCoCg)
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{
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real Y = YCoCg.x;
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real Co = YCoCg.y - YCOCG_CHROMA_BIAS;
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real Cg = YCoCg.z - YCOCG_CHROMA_BIAS;
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real3 rgb;
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rgb.r = Y + Co - Cg;
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rgb.g = Y + Cg;
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rgb.b = Y - Co - Cg;
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return rgb;
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}
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// Following function can be use to reconstruct chroma component for a checkboard YCoCg pattern
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// Reference: The Compact YCoCg Frame Buffer
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real YCoCgCheckBoardEdgeFilter(real centerLum, real2 a0, real2 a1, real2 a2, real2 a3)
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{
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real4 lum = real4(a0.x, a1.x, a2.x, a3.x);
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// Optimize: real4 w = 1.0 - step(30.0 / 255.0, abs(lum - centerLum));
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real4 w = 1.0 - saturate((abs(lum.xxxx - centerLum) - 30.0 / 255.0) * HALF_MAX);
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real W = w.x + w.y + w.z + w.w;
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// handle the special case where all the weights are zero.
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return (W == 0.0) ? a0.y : (w.x * a0.y + w.y* a1.y + w.z* a2.y + w.w * a3.y) / W;
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}
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// Hue, Saturation, Value
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// Ranges:
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// Hue [0.0, 1.0]
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// Sat [0.0, 1.0]
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// Lum [0.0, HALF_MAX]
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real3 RgbToHsv(real3 c)
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{
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const real4 K = real4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
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real4 p = lerp(real4(c.bg, K.wz), real4(c.gb, K.xy), step(c.b, c.g));
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real4 q = lerp(real4(p.xyw, c.r), real4(c.r, p.yzx), step(p.x, c.r));
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real d = q.x - min(q.w, q.y);
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const real e = 1.0e-4;
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return real3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
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}
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real3 HsvToRgb(real3 c)
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{
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const real4 K = real4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
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real3 p = abs(frac(c.xxx + K.xyz) * 6.0 - K.www);
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return c.z * lerp(K.xxx, saturate(p - K.xxx), c.y);
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}
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// SMPTE ST.2084 (PQ) transfer functions
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// 1.0 = 100nits, 100.0 = 10knits
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#define DEFAULT_MAX_PQ 100.0
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struct ParamsPQ
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{
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real N, M;
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real C1, C2, C3;
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};
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static const ParamsPQ PQ =
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{
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2610.0 / 4096.0 / 4.0, // N
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2523.0 / 4096.0 * 128.0, // M
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3424.0 / 4096.0, // C1
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2413.0 / 4096.0 * 32.0, // C2
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2392.0 / 4096.0 * 32.0, // C3
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};
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real3 LinearToPQ(real3 x, real maxPQValue)
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{
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x = PositivePow(x / maxPQValue, PQ.N);
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real3 nd = (PQ.C1 + PQ.C2 * x) / (1.0 + PQ.C3 * x);
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return PositivePow(nd, PQ.M);
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}
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real3 LinearToPQ(real3 x)
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{
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return LinearToPQ(x, DEFAULT_MAX_PQ);
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}
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real3 PQToLinear(real3 x, real maxPQValue)
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{
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x = PositivePow(x, rcp(PQ.M));
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real3 nd = max(x - PQ.C1, 0.0) / (PQ.C2 - (PQ.C3 * x));
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return PositivePow(nd, rcp(PQ.N)) * maxPQValue;
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}
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real3 PQToLinear(real3 x)
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{
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return PQToLinear(x, DEFAULT_MAX_PQ);
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}
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// Alexa LogC converters (El 1000)
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// See http://www.vocas.nl/webfm_send/964
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// Max range is ~58.85666
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// Set to 1 to use more precise but more expensive log/linear conversions. I haven't found a proper
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// use case for the high precision version yet so I'm leaving this to 0.
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#define USE_PRECISE_LOGC 0
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struct ParamsLogC
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{
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real cut;
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real a, b, c, d, e, f;
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};
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static const ParamsLogC LogC =
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{
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0.011361, // cut
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5.555556, // a
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0.047996, // b
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0.244161, // c
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0.386036, // d
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5.301883, // e
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0.092819 // f
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};
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real LinearToLogC_Precise(real x)
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{
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real o;
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if (x > LogC.cut)
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o = LogC.c * log10(LogC.a * x + LogC.b) + LogC.d;
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else
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o = LogC.e * x + LogC.f;
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return o;
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}
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real3 LinearToLogC(real3 x)
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{
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#if USE_PRECISE_LOGC
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return real3(
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LinearToLogC_Precise(x.x),
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LinearToLogC_Precise(x.y),
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LinearToLogC_Precise(x.z)
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);
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#else
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return LogC.c * log10(LogC.a * x + LogC.b) + LogC.d;
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#endif
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}
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real LogCToLinear_Precise(real x)
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{
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real o;
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if (x > LogC.e * LogC.cut + LogC.f)
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o = (pow(10.0, (x - LogC.d) / LogC.c) - LogC.b) / LogC.a;
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else
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o = (x - LogC.f) / LogC.e;
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return o;
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}
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real3 LogCToLinear(real3 x)
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{
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#if USE_PRECISE_LOGC
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return real3(
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LogCToLinear_Precise(x.x),
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LogCToLinear_Precise(x.y),
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LogCToLinear_Precise(x.z)
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);
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#else
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return (pow(10.0, (x - LogC.d) / LogC.c) - LogC.b) / LogC.a;
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#endif
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}
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//-----------------------------------------------------------------------------
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// Utilities
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//-----------------------------------------------------------------------------
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// Fast reversible tonemapper
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// http://gpuopen.com/optimized-reversible-tonemapper-for-resolve/
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real3 FastTonemap(real3 c)
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{
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return c * rcp(Max3(c.r, c.g, c.b) + 1.0);
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}
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real4 FastTonemap(real4 c)
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{
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return real4(FastTonemap(c.rgb), c.a);
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}
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real3 FastTonemap(real3 c, real w)
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{
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return c * (w * rcp(Max3(c.r, c.g, c.b) + 1.0));
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}
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real4 FastTonemap(real4 c, real w)
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{
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return real4(FastTonemap(c.rgb, w), c.a);
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}
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real3 FastTonemapInvert(real3 c)
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{
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return c * rcp(1.0 - Max3(c.r, c.g, c.b));
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}
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real4 FastTonemapInvert(real4 c)
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{
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return real4(FastTonemapInvert(c.rgb), c.a);
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}
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// 3D LUT grading
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// scaleOffset = (1 / lut_size, lut_size - 1)
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real3 ApplyLut3D(TEXTURE3D_ARGS(tex, samplerTex), real3 uvw, real2 scaleOffset)
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{
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real shift = floor(uvw.z);
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uvw.xy = uvw.xy * scaleOffset.y * scaleOffset.xx + scaleOffset.xx * 0.5;
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uvw.x += shift * scaleOffset.x;
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return SAMPLE_TEXTURE3D(tex, samplerTex, uvw).rgb;
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}
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// 2D LUT grading
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// scaleOffset = (1 / lut_width, 1 / lut_height, lut_height - 1)
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real3 ApplyLut2D(TEXTURE2D_ARGS(tex, samplerTex), real3 uvw, real3 scaleOffset)
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{
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// Strip format where `height = sqrt(width)`
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uvw.z *= scaleOffset.z;
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real shift = floor(uvw.z);
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uvw.xy = uvw.xy * scaleOffset.z * scaleOffset.xy + scaleOffset.xy * 0.5;
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uvw.x += shift * scaleOffset.y;
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uvw.xyz = lerp(
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SAMPLE_TEXTURE2D(tex, samplerTex, uvw.xy).rgb,
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SAMPLE_TEXTURE2D(tex, samplerTex, uvw.xy + real2(scaleOffset.y, 0.0)).rgb,
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uvw.z - shift
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);
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return uvw;
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}
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// Returns the default value for a given position on a 2D strip-format color lookup table
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// params = (lut_height, 0.5 / lut_width, 0.5 / lut_height, lut_height / lut_height - 1)
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real3 GetLutStripValue(real2 uv, real4 params)
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{
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uv -= params.yz;
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real3 color;
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color.r = frac(uv.x * params.x);
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color.b = uv.x - color.r / params.x;
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color.g = uv.y;
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return color * params.w;
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}
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#endif // UNITY_COLOR_INCLUDED
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