35 lines
1.0 KiB
GLSL
35 lines
1.0 KiB
GLSL
#ifdef GL_ES
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precision mediump float;
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#endif
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uniform sampler2D texture;
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uniform mat3 color_matrix;
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varying vec2 top_left_uv;
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varying vec2 top_right_uv;
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varying vec2 bottom_left_uv;
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varying vec2 bottom_right_uv;
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void main() {
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// Note the coordinates for texture samples need to be a varying, as the
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// Mali-400 has this as a fast path allowing 32-bit floats. Otherwise
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// they end up as 16-bit floats and that's not accurate enough.
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vec4 samples = vec4(
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texture2D(texture, top_left_uv).r,
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texture2D(texture, top_right_uv).r,
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texture2D(texture, bottom_left_uv).r,
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texture2D(texture, bottom_right_uv).r);
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// Assume BGGR for now. Currently this just takes 3 of the four samples
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// for each pixel, there's room here to do some better debayering.
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vec3 color = samples.wyx;
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// Fast SRGB estimate. See https://mimosa-pudica.net/fast-gamma/
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vec3 srgb_color = (vec3(1.138) * inversesqrt(color) - vec3(0.138)) * color;
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// Slow SRGB estimate
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// vec3 srgb_color = pow(color, vec3(1.0 / 2.2));
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gl_FragColor = vec4(color_matrix * srgb_color, 0);
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}
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