mirror of
https://github.com/italicsjenga/slang-shaders.git
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112 lines
3.7 KiB
Plaintext
112 lines
3.7 KiB
Plaintext
#version 450
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/*
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mix_frames_smart - performs 50:50 blending between the current and
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previous frames, but only if pixels repeatedly switch state on alternate
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frames (i.e. prevents flicker on games that use LCD ghosting for transparency,
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without blurring the entire screen). This is not 100% effective, but 'good
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enough' in many cases (e.g. it fixes map rendering issues in F-Zero GP on the GBA).
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Works best when flickering objects are in a fixed location.
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Author: jdgleaver
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This program is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at your option)
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any later version.
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*/
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// User-specified fudge factor. Increasing this value loosens up the
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// detection of repeated 'flicker' frames. This is required for
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// games like Boktai on the GBA, where the character shadow flickers
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// on and off between frames, but is sometimes overlaid with a screen
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// shading effect (so checking for pixel RGB equality fails - need to
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// check whether pixels are 'almost' equal)
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#pragma parameter DEFLICKER_EMPHASIS "Deflicker Emphasis" 0.0 0.0 1.0 0.01
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layout(push_constant) uniform Push
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{
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float DEFLICKER_EMPHASIS;
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} registers;
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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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} global;
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#pragma stage vertex
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layout(location = 0) in vec4 Position;
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layout(location = 1) in vec2 TexCoord;
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layout(location = 0) out vec2 vTexCoord;
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/*
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VERTEX_SHADER
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*/
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void main()
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{
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gl_Position = global.MVP * Position;
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vTexCoord = TexCoord;
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}
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#pragma stage fragment
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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 sampler2D Source;
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layout(set = 0, binding = 3) uniform sampler2D OriginalHistory1;
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layout(set = 0, binding = 4) uniform sampler2D OriginalHistory2;
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layout(set = 0, binding = 5) uniform sampler2D OriginalHistory3;
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layout(set = 0, binding = 6) uniform sampler2D OriginalHistory4;
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layout(set = 0, binding = 7) uniform sampler2D OriginalHistory5;
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#define EPSILON 0.000001
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float is_equal(vec3 x, vec3 y)
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{
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vec3 result = 1.0 - abs(sign(x - y));
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return min(min(result.r, result.g), result.b);
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}
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float is_approx_equal(vec3 x, vec3 y)
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{
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vec3 result = 1.0 - step(EPSILON + registers.DEFLICKER_EMPHASIS, abs(x - y));
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return min(min(result.r, result.g), result.b);
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}
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/*
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FRAGMENT SHADER
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*/
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void main()
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{
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// Get pixel colours of current + last 5 frames
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// NB: Using fewer frames results in too many false positives
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vec3 colour0 = texture(Source, vTexCoord.xy).rgb;
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vec3 colour1 = texture(OriginalHistory1, vTexCoord.xy).rgb;
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vec3 colour2 = texture(OriginalHistory2, vTexCoord.xy).rgb;
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vec3 colour3 = texture(OriginalHistory3, vTexCoord.xy).rgb;
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vec3 colour4 = texture(OriginalHistory4, vTexCoord.xy).rgb;
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vec3 colour5 = texture(OriginalHistory5, vTexCoord.xy).rgb;
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// Determine whether mixing should occur
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// i.e. whether alternate frames have the same pixel colour, but
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// adjacent frames do not (don't need to check colour0 != colour1,
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// since if this is true the mixing will do nothing)
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float doMix = (1.0 - is_equal(colour0, colour3))
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* (1.0 - is_equal(colour0, colour5))
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* (1.0 - is_equal(colour1, colour2))
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* (1.0 - is_equal(colour1, colour4))
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* (1.0 - is_equal(colour2, colour3))
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* (1.0 - is_equal(colour2, colour5))
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* min(
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(is_approx_equal(colour0, colour2) * is_approx_equal(colour2, colour4)) +
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(is_approx_equal(colour1, colour3) * is_approx_equal(colour3, colour5)),
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1.0
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);
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// Mix colours
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colour0.rgb = mix(colour0.rgb, colour1.rgb, doMix * 0.5);
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FragColor = vec4(colour0.rgb, 1.0);
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}
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