8daf812930* Sync of all the shaders from upstream + LoadFontData did not match anymore with C and crashed on MacOS * Updated JuliaSet demo. Did not work with the new shader version. * Removed unused `pause` variable from JuliaSet example. --------- Co-authored-by: Meatcorps <info@meatcorps.nl>
43 lines
1.5 KiB
GLSL
43 lines
1.5 KiB
GLSL
#version 100
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precision mediump float;
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const int MAX_INDEXED_COLORS = 8;
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// Input vertex attributes (from vertex shader)
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varying vec2 fragTexCoord;
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varying vec4 fragColor;
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// Input uniform values
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uniform sampler2D texture0;
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uniform ivec3 palette[MAX_INDEXED_COLORS];
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//uniform sampler2D palette; // Alternative to ivec3, palette provided as a 256x1 texture
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void main()
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{
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// Texel color fetching from texture sampler
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vec4 texelColor = texture2D(texture0, fragTexCoord)*fragColor;
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// Convert the (normalized) texel color RED component (GB would work, too)
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// to the palette index by scaling up from [0..1] to [0..255]
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int index = int(texelColor.r*255.0);
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ivec3 color = ivec3(0);
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// NOTE: On GLSL 100 we are not allowed to index a uniform array by a variable value,
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// a constant must be used, so this logic...
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if (index == 0) color = palette[0];
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else if (index == 1) color = palette[1];
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else if (index == 2) color = palette[2];
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else if (index == 3) color = palette[3];
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else if (index == 4) color = palette[4];
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else if (index == 5) color = palette[5];
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else if (index == 6) color = palette[6];
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else if (index == 7) color = palette[7];
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//gl_FragColor = texture2D(palette, texelColor.xy); // Alternative to ivec3
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// Calculate final fragment color. Note that the palette color components
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// are defined in the range [0..255] and need to be normalized to [0..1]
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gl_FragColor = vec4(float(color.x)/255.0, float(color.y)/255.0, float(color.z)/255.0, texelColor.a);
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}
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