mirror of
https://github.com/libretro/RetroArch
synced 2025-02-01 00:32:46 +00:00
113 lines
3.9 KiB
GLSL
113 lines
3.9 KiB
GLSL
#version 310 es
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precision highp float;
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layout(location = 0) in vec2 vTexCoord;
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layout(location = 0) out vec4 FragColor;
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layout(set = 0, binding = 2) uniform highp sampler2D Source;
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layout(std140, set = 0, binding = 0) uniform UBO
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{
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mat4 MVP;
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float contrast; /* 2.0f; */
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float paper_white_nits; /* 200.0f; */
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float max_nits; /* 1000.0f; */
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float expand_gamut; /* 1.0f; */
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float inverse_tonemap;
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float hdr10;
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} global;
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/* Inverse Tonemap section */
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#define kMaxNitsFor2084 10000.0f
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#define kEpsilon 0.0001f
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#define kLumaChannelRatio 0.25f
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vec3 InverseTonemap(vec3 sdr)
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{
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vec3 hdr;
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if(global.inverse_tonemap > 0.0f)
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{
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sdr = pow(abs(sdr), vec3(global.contrast / 2.2f)); /* Display Gamma - needs to be determined by calibration screen */
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float luma = dot(sdr, vec3(0.2126, 0.7152, 0.0722)); /* Rec BT.709 luma coefficients - https://en.wikipedia.org/wiki/Luma_(video) */
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/* Inverse reinhard tonemap */
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float maxValue = (global.max_nits / global.paper_white_nits) + kEpsilon;
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float elbow = maxValue / (maxValue - 1.0f);
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float offset = 1.0f - ((0.5f * elbow) / (elbow - 0.5f));
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float hdrLumaInvTonemap = offset + ((luma * elbow) / (elbow - luma));
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float sdrLumaInvTonemap = luma / ((1.0f + kEpsilon) - luma); /* Convert the srd < 0.5 to 0.0 -> 1.0 range */
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float lumaInvTonemap = (luma > 0.5f) ? hdrLumaInvTonemap : sdrLumaInvTonemap;
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vec3 perLuma = sdr / (luma + kEpsilon) * lumaInvTonemap;
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vec3 hdrInvTonemap = offset + ((sdr * elbow) / (elbow - sdr));
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vec3 sdrInvTonemap = sdr / ((1.0f + kEpsilon) - sdr); /* Convert the srd < 0.5 to 0.0 -> 1.0 range */
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vec3 perChannel = vec3(sdr.x > 0.5f ? hdrInvTonemap.x : sdrInvTonemap.x,
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sdr.y > 0.5f ? hdrInvTonemap.y : sdrInvTonemap.y,
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sdr.z > 0.5f ? hdrInvTonemap.z : sdrInvTonemap.z);
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hdr = mix(perLuma, perChannel, vec3(kLumaChannelRatio));
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}
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else
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{
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hdr = sdr;
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}
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return hdr;
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}
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/* HDR10 section */
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#define kMaxNitsFor2084 10000.0f
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const mat3 k709to2020 = mat3 (
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0.6274040f, 0.3292820f, 0.0433136f,
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0.0690970f, 0.9195400f, 0.0113612f,
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0.0163916f, 0.0880132f, 0.8955950f);
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/* START Converted from (Copyright (c) Microsoft Corporation - Licensed under the MIT License.) https://github.com/microsoft/Xbox-ATG-Samples/tree/master/Kits/ATGTK/HDR */
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const mat3 kExpanded709to2020 = mat3 (
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0.6274040f, 0.3292820f, 0.0433136f,
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0.0457456, 0.941777, 0.0124772,
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-0.00121055, 0.0176041, 0.983607);
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vec3 LinearToST2084(vec3 normalizedLinearValue)
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{
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vec3 ST2084 = pow((0.8359375f + 18.8515625f * pow(abs(normalizedLinearValue), vec3(0.1593017578f))) / (1.0f + 18.6875f * pow(abs(normalizedLinearValue), vec3(0.1593017578f))), vec3(78.84375f));
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return ST2084; /* Don't clamp between [0..1], so we can still perform operations on scene values higher than 10,000 nits */
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}
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/* END Converted from (Copyright (c) Microsoft Corporation - Licensed under the MIT License.) https://github.com/microsoft/Xbox-ATG-Samples/tree/master/Kits/ATGTK/HDR */
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vec3 Hdr10(vec3 hdr)
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{
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vec3 hdr10;
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if(global.hdr10 > 0.0f)
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{
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/* Now convert into HDR10 */
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vec3 rec2020 = hdr * k709to2020;
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if(global.expand_gamut > 0.0f)
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{
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rec2020 = hdr * kExpanded709to2020;
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}
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vec3 linearColour = rec2020 * (global.paper_white_nits / kMaxNitsFor2084);
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hdr10 = LinearToST2084(linearColour);
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}
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else
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{
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hdr10 = hdr;
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}
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return hdr10;
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}
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void main()
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{
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vec4 sdr = texture(Source, vTexCoord);
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vec4 hdr = vec4(InverseTonemap(sdr.rgb), sdr.a);
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FragColor = vec4(Hdr10(hdr.rgb), hdr.a);
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}
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