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return dot(linearRgb, float3(0.2126729f, 0.7151522f, 0.0721750f)); |
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} |
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float Luminance(float4 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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float 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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float3 RgbToHsv(float3 c) |
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{ |
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const float4 K = float4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0); |
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float4 p = lerp(float4(c.bg, K.wz), float4(c.gb, K.xy), step(c.b, c.g)); |
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float4 q = lerp(float4(p.xyw, c.r), float4(c.r, p.yzx), step(p.x, c.r)); |
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float d = q.x - min(q.w, q.y); |
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const float e = 1.0e-4; |
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return float3(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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float3 HsvToRgb(float3 c) |
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{ |
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const float4 K = float4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0); |
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float3 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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float N, M; |
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float 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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float3 LinearToPQ(float3 x, float maxPQValue) |
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{ |
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x = PositivePow(x / maxPQValue, PQ.N); |
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float3 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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float3 LinearToPQ(float3 x) |
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{ |
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return LinearToPQ(x, DEFAULT_MAX_PQ); |
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} |
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float3 PQToLinear(float3 x, float maxPQValue) |
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{ |
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x = PositivePow(x, rcp(PQ.M)); |
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float3 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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float3 PQToLinear(float3 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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float cut; |
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float 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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|
float LinearToLogC_Precise(half x) |
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|
{ |
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|
float 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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|
float3 LinearToLogC(float3 x) |
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|
{ |
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|
|
#if USE_PRECISE_LOGC |
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|
return float3( |
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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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|
float LogCToLinear_Precise(float x) |
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|
|
{ |
|
|
|
float 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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|
float3 LogCToLinear(float3 x) |
|
|
|
{ |
|
|
|
#if USE_PRECISE_LOGC |
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|
return float3( |
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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; |
|
|
|
#endif |
|
|
|
} |
|
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|
//----------------------------------------------------------------------------- |
|
|
|
// Utilities |
|
|
|
//----------------------------------------------------------------------------- |
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|
|
// Fast reversible tonemapper |
|
|
|
// http://gpuopen.com/optimized-reversible-tonemapper-for-resolve/ |
|
|
|
float3 FastTonemap(float3 c) |
|
|
|
{ |
|
|
|
return c * rcp(Max3(c.r, c.g, c.b) + 1.0); |
|
|
|
} |
|
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|
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|
|
float4 FastTonemap(float4 c) |
|
|
|
{ |
|
|
|
return float4(FastTonemap(c.rgb), c.a); |
|
|
|
} |
|
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|
|
float3 FastTonemap(float3 c, float w) |
|
|
|
{ |
|
|
|
return c * (w * rcp(Max3(c.r, c.g, c.b) + 1.0)); |
|
|
|
} |
|
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|
|
|
|
float4 FastTonemap(float4 c, float w) |
|
|
|
{ |
|
|
|
return float4(FastTonemap(c.rgb, w), c.a); |
|
|
|
} |
|
|
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|
|
|
|
float3 FastTonemapInvert(float3 c) |
|
|
|
{ |
|
|
|
return c * rcp(1.0 - Max3(c.r, c.g, c.b)); |
|
|
|
} |
|
|
|
|
|
|
|
float4 FastTonemapInvert(float4 c) |
|
|
|
{ |
|
|
|
return float4(FastTonemapInvert(c.rgb), c.a); |
|
|
|
} |
|
|
|
|
|
|
|
// 3D LUT grading |
|
|
|
// scaleOffset = (1 / lut_size, lut_size - 1) |
|
|
|
float3 ApplyLut3D(TEXTURE3D_ARGS(tex, samplerTex), float3 uvw, float2 scaleOffset) |
|
|
|
{ |
|
|
|
float shift = floor(uvw.z); |
|
|
|
uvw.xy = uvw.xy * scaleOffset.y * scaleOffset.xx + scaleOffset.xx * 0.5; |
|
|
|
uvw.x += shift * scaleOffset.x; |
|
|
|
return SAMPLE_TEXTURE3D(tex, samplerTex, uvw).rgb; |
|
|
|
} |
|
|
|
|
|
|
|
// 2D LUT grading |
|
|
|
// scaleOffset = (1 / lut_width, 1 / lut_height, lut_height - 1) |
|
|
|
float3 ApplyLut2D(TEXTURE2D_ARGS(tex, samplerTex), float3 uvw, float3 scaleOffset) |
|
|
|
{ |
|
|
|
// Strip format where `height = sqrt(width)` |
|
|
|
uvw.z *= scaleOffset.z; |
|
|
|
float shift = floor(uvw.z); |
|
|
|
uvw.xy = uvw.xy * scaleOffset.z * scaleOffset.xy + scaleOffset.xy * 0.5; |
|
|
|
uvw.x += shift * scaleOffset.y; |
|
|
|
uvw.xyz = lerp( |
|
|
|
SAMPLE_TEXTURE2D(tex, samplerTex, uvw.xy).rgb, |
|
|
|
SAMPLE_TEXTURE2D(tex, samplerTex, uvw.xy + float2(scaleOffset.y, 0.0)).rgb, |
|
|
|
uvw.z - shift |
|
|
|
); |
|
|
|
return uvw; |
|
|
|
} |
|
|
|
|
|
|
|
// Returns the default value for a given position on a 2D strip-format color lookup table |
|
|
|
// params = (lut_height, 0.5 / lut_width, 0.5 / lut_height, lut_height / lut_height - 1) |
|
|
|
float3 GetLutStripValue(float2 uv, float4 params) |
|
|
|
{ |
|
|
|
uv -= params.yz; |
|
|
|
float3 color; |
|
|
|
color.r = frac(uv.x * params.x); |
|
|
|
color.b = uv.x - color.r / params.x; |
|
|
|
color.g = uv.y; |
|
|
|
return color * params.w; |
|
|
|
} |
|
|
|
|
|
|
|
#endif // UNITY_COLOR_INCLUDED |
GitHub
7 年前