50 lines
2.0 KiB
HLSL
50 lines
2.0 KiB
HLSL
// Adapted from https://github.com/microsoft/terminal/blob/1283c0f5b99a2961673249fa77c6b986efb5086c/src/renderer/atlas/dwrite.hlsl
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// Copyright (c) Microsoft Corporation.
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// Licensed under the MIT license.
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float color_brightness(float3 color) {
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// REC. 601 luminance coefficients for perceived brightness
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return dot(color, float3(0.30f, 0.59f, 0.11f));
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}
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float light_on_dark_contrast(float enhancedContrast, float3 color) {
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float brightness = color_brightness(color);
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float multiplier = saturate(4.0f * (0.75f - brightness));
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return enhancedContrast * multiplier;
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}
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float enhance_contrast(float alpha, float k) {
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return alpha * (k + 1.0f) / (alpha * k + 1.0f);
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}
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float3 enhance_contrast3(float3 alpha, float k) {
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return alpha * (k + 1.0f) / (alpha * k + 1.0f);
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}
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float apply_alpha_correction(float a, float b, float4 g) {
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float brightness_adjustment = g.x * b + g.y;
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float correction = brightness_adjustment * a + (g.z * b + g.w);
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return a + a * (1.0f - a) * correction;
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}
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float3 apply_alpha_correction3(float3 a, float3 b, float4 g) {
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float3 brightness_adjustment = g.x * b + g.y;
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float3 correction = brightness_adjustment * a + (g.z * b + g.w);
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return a + a * (1.0f - a) * correction;
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}
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float apply_contrast_and_gamma_correction(float sample, float3 color, float enhanced_contrast_factor, float4 gamma_ratios) {
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float enhanced_contrast = light_on_dark_contrast(enhanced_contrast_factor, color);
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float brightness = color_brightness(color);
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float contrasted = enhance_contrast(sample, enhanced_contrast);
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return apply_alpha_correction(contrasted, brightness, gamma_ratios);
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}
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float3 apply_contrast_and_gamma_correction3(float3 sample, float3 color, float enhanced_contrast_factor, float4 gamma_ratios) {
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float enhanced_contrast = light_on_dark_contrast(enhanced_contrast_factor, color);
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float3 contrasted = enhance_contrast3(sample, enhanced_contrast);
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return apply_alpha_correction3(contrasted, color, gamma_ratios);
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}
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