mirror of
https://github.com/0ldsk00l/nestopia.git
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54 lines
2 KiB
GLSL
54 lines
2 KiB
GLSL
/*
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MIT License
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Sharp Bilinear (Modified)
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Copyright (c) 2020-2022 Rupert Carmichael
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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// Based on Public Domain work by Themaister
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precision highp float;
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uniform sampler2D source;
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uniform vec4 sourceSize;
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uniform vec4 targetSize;
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in vec2 texCoord;
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out vec4 fragColor;
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void main() {
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float prescale = floor(targetSize.y / sourceSize.y + 0.01);
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if (prescale == 0.0) prescale = 1.0;
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vec2 texel = texCoord.xy * sourceSize.xy;
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vec2 texel_floored = floor(texel);
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vec2 s = fract(texel);
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float region_range = 0.5 - 0.5 / prescale;
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/* Figure out where in the texel to sample to get correct pre-scaled
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bilinear. Uses the hardware bilinear interpolator to avoid having to
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sample 4 times manually.
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*/
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vec2 center_dist = s - 0.5;
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vec2 f = (center_dist - clamp(center_dist, -region_range, region_range)) *
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prescale + 0.5;
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vec2 mod_texel = texel_floored + f;
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fragColor = texture(source, mod_texel / sourceSize.xy);
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}
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