three
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JavaScript 3D library
201 lines (137 loc) • 5.26 kB
JavaScript
export default /* glsl */`
// <common> may have defined saturate() already
uniform float toneMappingExposure;
// exposure only
vec3 LinearToneMapping( vec3 color ) {
return saturate( toneMappingExposure * color );
}
// source: https://www.cs.utah.edu/docs/techreports/2002/pdf/UUCS-02-001.pdf
vec3 ReinhardToneMapping( vec3 color ) {
color *= toneMappingExposure;
return saturate( color / ( vec3( 1.0 ) + color ) );
}
// source: http://filmicworlds.com/blog/filmic-tonemapping-operators/
vec3 CineonToneMapping( vec3 color ) {
// filmic operator by Jim Hejl and Richard Burgess-Dawson
color *= toneMappingExposure;
color = max( vec3( 0.0 ), color - 0.004 );
return pow( ( color * ( 6.2 * color + 0.5 ) ) / ( color * ( 6.2 * color + 1.7 ) + 0.06 ), vec3( 2.2 ) );
}
// source: https://github.com/selfshadow/ltc_code/blob/master/webgl/shaders/ltc/ltc_blit.fs
vec3 RRTAndODTFit( vec3 v ) {
vec3 a = v * ( v + 0.0245786 ) - 0.000090537;
vec3 b = v * ( 0.983729 * v + 0.4329510 ) + 0.238081;
return a / b;
}
// this implementation of ACES is modified to accommodate a brighter viewing environment.
// the scale factor of 1/0.6 is subjective. see discussion in #19621.
vec3 ACESFilmicToneMapping( vec3 color ) {
// sRGB => XYZ => D65_2_D60 => AP1 => RRT_SAT
const mat3 ACESInputMat = mat3(
vec3( 0.59719, 0.07600, 0.02840 ), // transposed from source
vec3( 0.35458, 0.90834, 0.13383 ),
vec3( 0.04823, 0.01566, 0.83777 )
);
// ODT_SAT => XYZ => D60_2_D65 => sRGB
const mat3 ACESOutputMat = mat3(
vec3( 1.60475, -0.10208, -0.00327 ), // transposed from source
vec3( -0.53108, 1.10813, -0.07276 ),
vec3( -0.07367, -0.00605, 1.07602 )
);
color *= toneMappingExposure / 0.6;
color = ACESInputMat * color;
// Apply RRT and ODT
color = RRTAndODTFit( color );
color = ACESOutputMat * color;
// Clamp to [0, 1]
return saturate( color );
}
// Matrices for rec 2020 <> rec 709 color space conversion
// matrix provided in row-major order so it has been transposed
// https://www.itu.int/pub/R-REP-BT.2407-2017
const mat3 LINEAR_REC2020_TO_LINEAR_SRGB = mat3(
vec3( 1.6605, - 0.1246, - 0.0182 ),
vec3( - 0.5876, 1.1329, - 0.1006 ),
vec3( - 0.0728, - 0.0083, 1.1187 )
);
const mat3 LINEAR_SRGB_TO_LINEAR_REC2020 = mat3(
vec3( 0.6274, 0.0691, 0.0164 ),
vec3( 0.3293, 0.9195, 0.0880 ),
vec3( 0.0433, 0.0113, 0.8956 )
);
// https://iolite-engine.com/blog_posts/minimal_agx_implementation
// Mean error^2: 3.6705141e-06
vec3 agxDefaultContrastApprox( vec3 x ) {
vec3 x2 = x * x;
vec3 x4 = x2 * x2;
return + 15.5 * x4 * x2
- 40.14 * x4 * x
+ 31.96 * x4
- 6.868 * x2 * x
+ 0.4298 * x2
+ 0.1191 * x
- 0.00232;
}
// AgX Tone Mapping implementation based on Filament, which in turn is based
// on Blender's implementation using rec 2020 primaries
// https://github.com/google/filament/pull/7236
// Inputs and outputs are encoded as Linear-sRGB.
vec3 AgXToneMapping( vec3 color ) {
// AgX constants
const mat3 AgXInsetMatrix = mat3(
vec3( 0.856627153315983, 0.137318972929847, 0.11189821299995 ),
vec3( 0.0951212405381588, 0.761241990602591, 0.0767994186031903 ),
vec3( 0.0482516061458583, 0.101439036467562, 0.811302368396859 )
);
// explicit AgXOutsetMatrix generated from Filaments AgXOutsetMatrixInv
const mat3 AgXOutsetMatrix = mat3(
vec3( 1.1271005818144368, - 0.1413297634984383, - 0.14132976349843826 ),
vec3( - 0.11060664309660323, 1.157823702216272, - 0.11060664309660294 ),
vec3( - 0.016493938717834573, - 0.016493938717834257, 1.2519364065950405 )
);
// LOG2_MIN = -10.0
// LOG2_MAX = +6.5
// MIDDLE_GRAY = 0.18
const float AgxMinEv = - 12.47393; // log2( pow( 2, LOG2_MIN ) * MIDDLE_GRAY )
const float AgxMaxEv = 4.026069; // log2( pow( 2, LOG2_MAX ) * MIDDLE_GRAY )
color *= toneMappingExposure;
color = LINEAR_SRGB_TO_LINEAR_REC2020 * color;
color = AgXInsetMatrix * color;
// Log2 encoding
color = max( color, 1e-10 ); // avoid 0 or negative numbers for log2
color = log2( color );
color = ( color - AgxMinEv ) / ( AgxMaxEv - AgxMinEv );
color = clamp( color, 0.0, 1.0 );
// Apply sigmoid
color = agxDefaultContrastApprox( color );
// Apply AgX look
// v = agxLook(v, look);
color = AgXOutsetMatrix * color;
// Linearize
color = pow( max( vec3( 0.0 ), color ), vec3( 2.2 ) );
color = LINEAR_REC2020_TO_LINEAR_SRGB * color;
// Gamut mapping. Simple clamp for now.
color = clamp( color, 0.0, 1.0 );
return color;
}
// https://modelviewer.dev/examples/tone-mapping
vec3 NeutralToneMapping( vec3 color ) {
const float StartCompression = 0.8 - 0.04;
const float Desaturation = 0.15;
color *= toneMappingExposure;
float x = min( color.r, min( color.g, color.b ) );
float offset = x < 0.08 ? x - 6.25 * x * x : 0.04;
color -= offset;
float peak = max( color.r, max( color.g, color.b ) );
if ( peak < StartCompression ) return color;
float d = 1. - StartCompression;
float newPeak = 1. - d * d / ( peak + d - StartCompression );
color *= newPeak / peak;
float g = 1. - 1. / ( Desaturation * ( peak - newPeak ) + 1. );
return mix( color, vec3( newPeak ), g );
}
vec3 CustomToneMapping( vec3 color ) { return color; }
`;