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[orx-color, orx-fx] turbo_colormap and spectral_zucconi6 provided as shader phrases (#338)

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This commit is contained in:
Kazik Pogoda
2024-06-10 11:52:25 +02:00
committed by GitHub
parent ab0970ce49
commit f43a322cb0
28 changed files with 503 additions and 115 deletions
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57
orx-fx/src/shaders/glsl/colormap/spectral-zucconi-colormap.frag
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@@ -1,18 +1,4 @@
// Spectral Colour Schemes
// By Alan Zucconi
// Website: www.alanzucconi.com
// Twitter: @AlanZucconi
// Example of different spectral colour schemes
// to convert visible wavelengths of light (400-700 nm) to RGB colours.
// The function "spectral_zucconi6" provides the best approximation
// without including any branching.
// Its faster version, "spectral_zucconi", is advised for mobile applications.
// Read "Improving the Rainbow" for more information
// http://www.alanzucconi.com/?p=6703
#pragma import colormap.spectral_zucconi6
#ifdef OR_IN_OUT
in vec2 v_texCoord0;
@@ -29,47 +15,6 @@ uniform float curve;
out vec4 o_color;
#endif
float saturate (float x)
{
return min(1.0, max(0.0,x));
}
vec3 saturate (vec3 x)
{
return min(vec3(1.,1.,1.), max(vec3(0.,0.,0.),x));
}
// --- Spectral Zucconi --------------------------------------------
// By Alan Zucconi
// Based on GPU Gems: https://developer.nvidia.com/sites/all/modules/custom/gpugems/books/GPUGems/gpugems_ch08.html
// But with values optimised to match as close as possible the visible spectrum
// Fits this: https://commons.wikimedia.org/wiki/File:Linear_visible_spectrum.svg
// With weighter MSE (RGB weights: 0.3, 0.59, 0.11)
vec3 bump3y (vec3 x, vec3 yoffset)
{
vec3 y = vec3(1.,1.,1.) - x * x;
y = saturate(y-yoffset);
return y;
}
// --- Spectral Zucconi 6 --------------------------------------------
// Based on GPU Gems
// Optimised by Alan Zucconi
vec3 spectral_zucconi6 (float x)
{
const vec3 c1 = vec3(3.54585104, 2.93225262, 2.41593945);
const vec3 x1 = vec3(0.69549072, 0.49228336, 0.27699880);
const vec3 y1 = vec3(0.02312639, 0.15225084, 0.52607955);
const vec3 c2 = vec3(3.90307140, 3.21182957, 3.96587128);
const vec3 x2 = vec3(0.11748627, 0.86755042, 0.66077860);
const vec3 y2 = vec3(0.84897130, 0.88445281, 0.73949448);
return
bump3y(c1 * (x - x1), y1) +
bump3y(c2 * (x - x2), y2);
}
void main() {
#ifndef OR_GL_TEXTURE2D
float red = texture(tex0, v_texCoord0).r;

35
orx-fx/src/shaders/glsl/colormap/turbo-colormap.frag
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@@ -1,13 +1,4 @@
// TurboColormap
// 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)
#pragma import colormap.turbo_colormap
#ifdef OR_IN_OUT
in vec2 v_texCoord0;
@@ -24,28 +15,6 @@ uniform float curve;
out vec4 o_color;
#endif
float saturate(in float x) {
return max(0, min(1, x));
}
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)
);
}
void main() {
#ifndef OR_GL_TEXTURE2D
float red = texture(tex0, v_texCoord0).r;
@@ -53,7 +22,7 @@ void main() {
float red = texture2D(tex0, v_texCoord0).r;
#endif
float value = (red - minValue) / (maxValue - minValue);
vec3 color = TurboColormap(pow(value, curve));
vec3 color = turbo_colormap(pow(value, curve));
color *= step(value, 1.) * step(0., value);
vec4 result = vec4(color, 1.);
#ifdef OR_GL_FRAGCOLOR