Turbo Colormap Polynomial Approximation in GLSL
// Copyright 2019 Google LLC. | |
// SPDX-License-Identifier: Apache-2.0 | |
// Polynomial approximation in GLSL for the Turbo colormap | |
// Original LUT: https://gist.github.com/mikhailov-work/ee72ba4191942acecc03fe6da94fc73f | |
// Authors: | |
// Colormap Design: Anton Mikhailov (mikhailov@google.com) | |
// GLSL Approximation: Ruofei Du (ruofei@google.com) | |
vec3 TurboColormap(in float x) { | |
const vec4 kRedVec4 = vec4(0.13572138, 4.61539260, -42.66032258, 132.13108234); | |
const vec4 kGreenVec4 = vec4(0.09140261, 2.19418839, 4.84296658, -14.18503333); | |
const vec4 kBlueVec4 = vec4(0.10667330, 12.64194608, -60.58204836, 110.36276771); | |
const vec2 kRedVec2 = vec2(-152.94239396, 59.28637943); | |
const vec2 kGreenVec2 = vec2(4.27729857, 2.82956604); | |
const vec2 kBlueVec2 = vec2(-89.90310912, 27.34824973); | |
x = saturate(x); | |
vec4 v4 = vec4( 1.0, x, x * x, x * x * x); | |
vec2 v2 = v4.zw * v4.z; | |
return vec3( | |
dot(v4, kRedVec4) + dot(v2, kRedVec2), | |
dot(v4, kGreenVec4) + dot(v2, kGreenVec2), | |
dot(v4, kBlueVec4) + dot(v2, kBlueVec2) | |
); | |
} |
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