262 lines
11 KiB
Plaintext
262 lines
11 KiB
Plaintext
Shader "Hidden/Universal Render Pipeline/LutBuilderHdr"
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{
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HLSLINCLUDE
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#pragma multi_compile_local _ _TONEMAP_ACES _TONEMAP_NEUTRAL
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#pragma multi_compile_local_fragment _ HDR_COLORSPACE_CONVERSION
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#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
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#include "Packages/com.unity.render-pipelines.universal/Shaders/PostProcessing/Common.hlsl"
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/ACES.hlsl"
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
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#if defined(HDR_COLORSPACE_CONVERSION)
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/HDROutput.hlsl"
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#endif
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float4 _Lut_Params; // x: lut_height, y: 0.5 / lut_width, z: 0.5 / lut_height, w: lut_height / lut_height - 1
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float4 _ColorBalance; // xyz: LMS coeffs, w: unused
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float4 _ColorFilter; // xyz: color, w: unused
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float4 _ChannelMixerRed; // xyz: rgb coeffs, w: unused
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float4 _ChannelMixerGreen; // xyz: rgb coeffs, w: unused
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float4 _ChannelMixerBlue; // xyz: rgb coeffs, w: unused
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float4 _HueSatCon; // x: hue shift, y: saturation, z: contrast, w: unused
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float4 _Lift; // xyz: color, w: unused
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float4 _Gamma; // xyz: color, w: unused
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float4 _Gain; // xyz: color, w: unused
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float4 _Shadows; // xyz: color, w: unused
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float4 _Midtones; // xyz: color, w: unused
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float4 _Highlights; // xyz: color, w: unused
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float4 _ShaHiLimits; // xy: shadows min/max, zw: highlight min/max
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float4 _SplitShadows; // xyz: color, w: balance
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float4 _SplitHighlights; // xyz: color, w: unused
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float4 _HDROutputLuminanceParams; // xy: brightness min/max, z: paper white brightness, w: 1.0 / brightness max
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float4 _HDROutputGradingParams; // x: eetf/range reduction mode, y: hue shift, zw: unused
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TEXTURE2D(_CurveMaster);
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TEXTURE2D(_CurveRed);
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TEXTURE2D(_CurveGreen);
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TEXTURE2D(_CurveBlue);
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TEXTURE2D(_CurveHueVsHue);
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TEXTURE2D(_CurveHueVsSat);
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TEXTURE2D(_CurveSatVsSat);
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TEXTURE2D(_CurveLumVsSat);
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#define MinNits _HDROutputLuminanceParams.x
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#define MaxNits _HDROutputLuminanceParams.y
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#define PaperWhite _HDROutputLuminanceParams.z
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#define RangeReductionMode (int)_HDROutputGradingParams.x
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#define HueShift _HDROutputGradingParams.y
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float EvaluateCurve(TEXTURE2D(curve), float t)
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{
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float x = SAMPLE_TEXTURE2D(curve, sampler_LinearClamp, float2(t, 0.0)).x;
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return saturate(x);
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}
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float3 RotateToColorGradeOutputSpace(float3 gradedColor)
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{
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#ifdef _TONEMAP_ACES
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// In ACES workflow we return graded color in ACEScg, we move to ACES (AP0) later on
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return gradedColor;
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#elif defined(HDR_COLORSPACE_CONVERSION) // HDR but not ACES workflow
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// If we are doing HDR we expect grading to finish at Rec2020. Any supplemental rotation is done inside the various options.
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return RotateRec709ToRec2020(gradedColor);
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#else // Nor ACES or HDR
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// We already graded in sRGB
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return gradedColor;
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#endif
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}
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// Note: when the ACES tonemapper is selected the grading steps will be done using ACES spaces
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float3 ColorGrade(float3 colorLutSpace)
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{
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// Switch back to linear
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float3 colorLinear = LogCToLinear(colorLutSpace);
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// White balance in LMS space
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float3 colorLMS = LinearToLMS(colorLinear);
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colorLMS *= _ColorBalance.xyz;
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colorLinear = LMSToLinear(colorLMS);
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// Do contrast in log after white balance
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#if _TONEMAP_ACES
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float3 colorLog = ACES_to_ACEScc(unity_to_ACES(colorLinear));
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#else
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float3 colorLog = LinearToLogC(colorLinear);
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#endif
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colorLog = (colorLog - ACEScc_MIDGRAY) * _HueSatCon.z + ACEScc_MIDGRAY;
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#if _TONEMAP_ACES
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colorLinear = ACES_to_ACEScg(ACEScc_to_ACES(colorLog));
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#else
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colorLinear = LogCToLinear(colorLog);
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#endif
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// Color filter is just an unclipped multiplier
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colorLinear *= _ColorFilter.xyz;
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// Do NOT feed negative values to the following color ops
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colorLinear = max(0.0, colorLinear);
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// Split toning
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// As counter-intuitive as it is, to make split-toning work the same way it does in Adobe
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// products we have to do all the maths in gamma-space...
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float balance = _SplitShadows.w;
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float3 colorGamma = PositivePow(colorLinear, 1.0 / 2.2);
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float luma = saturate(GetLuminance(saturate(colorGamma)) + balance);
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float3 splitShadows = lerp((0.5).xxx, _SplitShadows.xyz, 1.0 - luma);
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float3 splitHighlights = lerp((0.5).xxx, _SplitHighlights.xyz, luma);
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colorGamma = SoftLight(colorGamma, splitShadows);
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colorGamma = SoftLight(colorGamma, splitHighlights);
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colorLinear = PositivePow(colorGamma, 2.2);
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// Channel mixing (Adobe style)
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colorLinear = float3(
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dot(colorLinear, _ChannelMixerRed.xyz),
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dot(colorLinear, _ChannelMixerGreen.xyz),
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dot(colorLinear, _ChannelMixerBlue.xyz)
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);
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// Shadows, midtones, highlights
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luma = GetLuminance(colorLinear);
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float shadowsFactor = 1.0 - smoothstep(_ShaHiLimits.x, _ShaHiLimits.y, luma);
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float highlightsFactor = smoothstep(_ShaHiLimits.z, _ShaHiLimits.w, luma);
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float midtonesFactor = 1.0 - shadowsFactor - highlightsFactor;
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colorLinear = colorLinear * _Shadows.xyz * shadowsFactor
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+ colorLinear * _Midtones.xyz * midtonesFactor
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+ colorLinear * _Highlights.xyz * highlightsFactor;
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// Lift, gamma, gain
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colorLinear = colorLinear * _Gain.xyz + _Lift.xyz;
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colorLinear = sign(colorLinear) * pow(abs(colorLinear), _Gamma.xyz);
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// HSV operations
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float satMult;
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float3 hsv = RgbToHsv(colorLinear);
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{
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// Hue Vs Sat
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satMult = EvaluateCurve(_CurveHueVsSat, hsv.x) * 2.0;
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// Sat Vs Sat
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satMult *= EvaluateCurve(_CurveSatVsSat, hsv.y) * 2.0;
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// Lum Vs Sat
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satMult *= EvaluateCurve(_CurveLumVsSat, Luminance(colorLinear)) * 2.0;
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// Hue Shift & Hue Vs Hue
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float hue = hsv.x + _HueSatCon.x;
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float offset = EvaluateCurve(_CurveHueVsHue, hue) - 0.5;
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hue += offset;
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hsv.x = RotateHue(hue, 0.0, 1.0);
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}
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colorLinear = HsvToRgb(hsv);
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// Global saturation
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luma = GetLuminance(colorLinear);
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colorLinear = luma.xxx + (_HueSatCon.yyy * satMult) * (colorLinear - luma.xxx);
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// YRGB curves
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// Conceptually these need to be in range [0;1] and from an artist-workflow perspective
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// it's easier to deal with
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colorLinear = FastTonemap(colorLinear);
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{
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const float kHalfPixel = (1.0 / 128.0) / 2.0;
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float3 c = colorLinear;
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// Y (master)
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c += kHalfPixel.xxx;
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float mr = EvaluateCurve(_CurveMaster, c.r);
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float mg = EvaluateCurve(_CurveMaster, c.g);
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float mb = EvaluateCurve(_CurveMaster, c.b);
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c = float3(mr, mg, mb);
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// RGB
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c += kHalfPixel.xxx;
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float r = EvaluateCurve(_CurveRed, c.r);
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float g = EvaluateCurve(_CurveGreen, c.g);
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float b = EvaluateCurve(_CurveBlue, c.b);
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colorLinear = float3(r, g, b);
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}
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colorLinear = FastTonemapInvert(colorLinear);
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colorLinear = max(0.0, colorLinear);
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return RotateToColorGradeOutputSpace(colorLinear);
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}
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float3 Tonemap(float3 colorLinear)
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{
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#if _TONEMAP_NEUTRAL
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{
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colorLinear = NeutralTonemap(colorLinear);
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}
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#elif _TONEMAP_ACES
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{
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// Note: input is actually ACEScg (AP1 w/ linear encoding)
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float3 aces = ACEScg_to_ACES(colorLinear);
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colorLinear = AcesTonemap(aces);
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}
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#endif
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return colorLinear;
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}
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float3 ProcessColorForHDR(float3 colorLinear)
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{
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#ifdef HDR_COLORSPACE_CONVERSION
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#ifdef _TONEMAP_ACES
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float3 aces = ACEScg_to_ACES(colorLinear);
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return HDRMappingACES(aces.rgb, PaperWhite, MinNits, MaxNits, RangeReductionMode, true);
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#elif _TONEMAP_NEUTRAL
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return HDRMappingFromRec2020(colorLinear.rgb, PaperWhite, MinNits, MaxNits, RangeReductionMode, HueShift, true);
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#else
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// Grading finished in Rec2020, converting to the expected color space and [0, 10k] nits range
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return RotateRec2020ToOutputSpace(colorLinear) * PaperWhite;
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#endif
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#endif
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return colorLinear;
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}
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float4 FragLutBuilderHdr(Varyings input) : SV_Target
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{
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// Lut space
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// We use Alexa LogC (El 1000) to store the LUT as it provides a good enough range
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// (~58.85666) and is good enough to be stored in fp16 without losing precision in the
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// darks
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float3 colorLutSpace = GetLutStripValue(input.texcoord, _Lut_Params);
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// Color grade & tonemap
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float3 gradedColor = ColorGrade(colorLutSpace);
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#ifdef HDR_COLORSPACE_CONVERSION
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gradedColor = ProcessColorForHDR(gradedColor);
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#else
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gradedColor = Tonemap(gradedColor);
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#endif
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return float4(gradedColor, 1.0);
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}
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ENDHLSL
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SubShader
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{
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Tags { "RenderType" = "Opaque" "RenderPipeline" = "UniversalPipeline"}
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LOD 100
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ZTest Always ZWrite Off Cull Off
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Pass
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{
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Name "LutBuilderHdr"
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HLSLPROGRAM
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#pragma vertex Vert
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#pragma fragment FragLutBuilderHdr
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ENDHLSL
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}
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}
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}
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