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61 lines
2.4 KiB
C
61 lines
2.4 KiB
C
#ifndef WHITE_POINT
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#define WHITE_POINT
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// White Point Mapping
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// ported by Dogway
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//
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// From the first comment post (sRGB primaries and linear light compensated)
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// http://www.zombieprototypes.com/?p=210#comment-4695029660
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// Based on the Neil Bartlett's blog update
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// http://www.zombieprototypes.com/?p=210
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// Inspired itself by Tanner Helland's work
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// http://www.tannerhelland.com/4435/convert-temperature-rgb-algorithm-code
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#include "col_tools.h"
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#pragma parameter temperature "White Point" 6500.0 1031.0 12047.0 72.0
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#pragma parameter luma_preserve "Preserve Luminance" 1.0 0.0 1.0 1.0
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#pragma parameter wp_red "Red Shift" 0.0 -1.0 1.0 0.01
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#pragma parameter wp_green "Green Shift" 0.0 -1.0 1.0 0.01
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#pragma parameter wp_blue "Blue Shift" 0.0 -1.0 1.0 0.01
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vec3 wp_adjust(vec3 color){
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float temp = temperature / 100.;
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float k = temperature / 10000.;
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float lk = log(k);
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vec3 wp = vec3(1.);
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// calculate RED
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wp.r = (temp <= 65.) ? 1. : 0.32068362618584273 + (0.19668730877673762 * pow(k - 0.21298613432655075, - 1.5139012907556737)) + (- 0.013883432789258415 * lk);
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// calculate GREEN
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float mg = 1.226916242502167 + (- 1.3109482654223614 * pow(k - 0.44267061967913873, 3.) * exp(- 5.089297600846147 * (k - 0.44267061967913873))) + (0.6453936305542096 * lk);
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float pg = 0.4860175851734596 + (0.1802139719519286 * pow(k - 0.14573069517701578, - 1.397716496795082)) + (- 0.00803698899233844 * lk);
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wp.g = (temp <= 65.5) ? ((temp <= 8.) ? 0. : mg) : pg;
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// calculate BLUE
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wp.b = (temp <= 19.) ? 0. : (temp >= 66.) ? 1. : 1.677499032830161 + (- 0.02313594016938082 * pow(k - 1.1367244820333684, 3.) * exp(- 4.221279555918655 * (k - 1.1367244820333684))) + (1.6550275798913296 * lk);
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// clamp
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wp.rgb = clamp(wp.rgb, vec3(0.), vec3(1.));
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// R/G/B independent manual White Point adjustment
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wp.rgb += vec3(wp_red, wp_green, wp_blue);
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// Linear color input
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return color * wp;
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}
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vec3 white_point(vec3 in_col){
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vec3 original = sRGB_to_linear(in_col, 2.20);
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vec3 adjusted = wp_adjust(original);
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vec3 base_luma = XYZtoYxy(sRGB_to_XYZ(original));
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vec3 adjusted_luma = XYZtoYxy(sRGB_to_XYZ(adjusted));
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adjusted = (luma_preserve > 0.5) ? adjusted_luma + (vec3(base_luma.r,0.,0.) - vec3(adjusted_luma.r,0.,0.)) : adjusted_luma;
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return linear_to_sRGB(XYZ_to_sRGB(YxytoXYZ(adjusted)), 2.20);
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}
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#endif
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