48 lines
1.9 KiB
GLSL
48 lines
1.9 KiB
GLSL
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precision mediump float;
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varying vec2 v_texcoord;
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uniform sampler2D tex;
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const float temperature = 3500.0;
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const float temperatureStrength = 1.0;
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#define WithQuickAndDirtyLuminancePreservation
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const float LuminancePreservationFactor = 1.0;
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// function from https://www.shadertoy.com/view/4sc3D7
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// valid from 1000 to 40000 K (and additionally 0 for pure full white)
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vec3 colorTemperatureToRGB(const in float temperature){
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// values from: http://blenderartists.org/forum/showthread.php?270332-OSL-Goodness&p=2268693&viewfull=1#post2268693
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mat3 m = (temperature <= 6500.0) ? mat3(vec3(0.0, -2902.1955373783176, -8257.7997278925690),
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vec3(0.0, 1669.5803561666639, 2575.2827530017594),
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vec3(1.0, 1.3302673723350029, 1.8993753891711275)) :
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mat3(vec3(1745.0425298314172, 1216.6168361476490, -8257.7997278925690),
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vec3(-2666.3474220535695, -2173.1012343082230, 2575.2827530017594),
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vec3(0.55995389139931482, 0.70381203140554553, 1.8993753891711275));
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return mix(
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clamp(vec3(m[0] / (vec3(clamp(temperature, 1000.0, 40000.0)) + m[1]) + m[2]), vec3(0.0), vec3(1.0)),
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vec3(1.0),
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smoothstep(1000.0, 0.0, temperature)
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);
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}
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void main() {
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vec4 pixColor = texture2D(tex, v_texcoord);
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// RGB
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vec3 color = vec3(pixColor[0], pixColor[1], pixColor[2]);
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#ifdef WithQuickAndDirtyLuminancePreservation
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color *= mix(1.0,
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dot(color, vec3(0.2126, 0.7152, 0.0722)) / max(dot(color, vec3(0.2126, 0.7152, 0.0722)), 1e-5),
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LuminancePreservationFactor);
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#endif
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color = mix(color, color * colorTemperatureToRGB(temperature), temperatureStrength);
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vec4 outCol = vec4(color, pixColor[3]);
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gl_FragColor = outCol;
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}
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