mirror of
https://github.com/tanema/light_world.lua.git
synced 2024-12-24 20:24:19 +00:00
160 lines
4.2 KiB
GLSL
160 lines
4.2 KiB
GLSL
/*
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caligari's scanlines
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Copyright (C) 2011 caligari
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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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(caligari gave their consent to have this shader distributed under the GPL
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in this message:
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http://board.byuu.org/viewtopic.php?p=36219#p36219
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"As I said to Hyllian by PM, I'm fine with the GPL (not really a bi
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deal...)"
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)
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*/
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extern vec2 textureSize;
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// 0.5 = the spot stays inside the original pixel
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// 1.0 = the spot bleeds up to the center of next pixel
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#define PHOSPHOR_WIDTH 0.9
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#define PHOSPHOR_HEIGHT 0.65
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// Used to counteract the desaturation effect of weighting.
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#define COLOR_BOOST 1.9
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// Constants used with gamma correction.
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#define InputGamma 2.4
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#define OutputGamma 2.2
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// Uncomment to only draw every third pixel, which highlights the shape
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// of individual (remaining) spots.
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// #define DEBUG
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// Uncomment one of these to choose a gamma correction method.
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// If none are uncommented, no gamma correction is done.
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// #define REAL_GAMMA
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#define FAKE_GAMMA
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// #define FAKER_GAMMA
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#ifdef REAL_GAMMA
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#define GAMMA_IN(color) pow(color, vec4(InputGamma))
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#define GAMMA_OUT(color) pow(color, vec4(1.0 / OutputGamma))
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#elif defined FAKE_GAMMA
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/*
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* Approximations:
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* for 1<g<2 : x^g ~ ax + bx^2
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* where a=6/(g+1)-2 and b=1-a
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* for 2<g<3 : x^g ~ ax^2 + bx^3
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* where a=12/(g+1)-3 and b=1-a
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* for 1<g<2 : x^(1/g) ~ (sqrt(a^2+4bx)-a)
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* where a=6/(g+1)-2 and b=1-a
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* for 2<g<3 : x^(1/g) ~ (a sqrt(x) + b sqrt(sqrt(x)))
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* where a = 6 - 15g / 2(g+1) and b = 1-a
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*/
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vec4 A_IN = vec4( 12.0/(InputGamma+1.0)-3.0 );
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vec4 B_IN = vec4(1.0) - A_IN;
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vec4 A_OUT = vec4(6.0 - 15.0 * OutputGamma / 2.0 / (OutputGamma+1.0));
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vec4 B_OUT = vec4(1.0) - A_OUT;
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#define GAMMA_IN(color) ( (A_IN + B_IN * color) * color * color )
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#define GAMMA_OUT(color) ( A_OUT * sqrt(color) + B_OUT * sqrt( sqrt(color) ) )
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#elif defined FAKER_GAMMA
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vec4 A_IN = vec4(6.0/( InputGamma/OutputGamma + 1.0 ) - 2.0);
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vec4 B_IN = vec4(1.0) - A_IN;
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#define GAMMA_IN(color) ( (A_IN + B_IN * color) * color )
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#define GAMMA_OUT(color) color
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#else // No gamma correction
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#define GAMMA_IN(color) color
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#define GAMMA_OUT(color) color
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#endif
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#ifdef DEBUG
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vec4 grid_color( vec2 coords )
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{
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vec2 snes = floor( coords * textureSize );
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if ( (mod(snes.x, 3.0) == 0.0) && (mod(snes.y, 3.0) == 0.0) )
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return texture2D(_tex0_, coords);
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else
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return vec4(0.0);
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}
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#define TEX2D(coords) GAMMA_IN( grid_color( coords ) )
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#else // DEBUG
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#define TEX2D(coords) GAMMA_IN( texture2D(_tex0_, coords) )
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#endif // DEBUG
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vec2 onex = vec2( 1.0/textureSize.x, 0.0 );
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vec2 oney = vec2( 0.0, 1.0/textureSize.y );
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vec4 effect(vec4 vcolor, Image texture, vec2 texCoord, vec2 pixel_coords)
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{
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vec2 coords = (texCoord * textureSize);
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vec2 pixel_start = floor(coords);
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coords -= pixel_start;
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vec2 pixel_center = pixel_start + vec2(0.5);
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vec2 texture_coords = pixel_center / textureSize;
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vec4 color = vec4(0.0);
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vec4 pixel;
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vec3 centers = vec3(-0.25,-0.5,-0.75);
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vec3 posx = vec3(coords.x);
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vec3 hweight;
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float vweight;
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float dx,dy;
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float w;
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float i,j;
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for (j = -1.0; j<=1.0; j++) {
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// Vertical weight
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dy = abs(coords.y - 0.5 - j );
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vweight = smoothstep(1.0,0.0, dy / PHOSPHOR_HEIGHT);
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if (vweight !=0.0 ) {
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for ( i = -1.0; i<=1.0; i++ ) {
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pixel = TEX2D(
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texture_coords
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+ i * onex
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+ j * oney
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);
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/* Evaluate the distance (in x) from
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* the pixel (posx) to the RGB centers
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* (~centers):
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* x_red = 0.25
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* x_green = 0.5
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* x_blue = 0.75
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* if the distance > PHOSPHOR_WIDTH,
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* this pixel doesn't contribute
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* otherwise, smoothstep gives the
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* weight of the contribution
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*/
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hweight = smoothstep(
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1.0, 0.0,
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abs((posx + centers - vec3(i))
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/ vec3(PHOSPHOR_WIDTH))
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);
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color.rgb +=
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pixel.rgb *
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hweight *
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vec3(vweight);
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}
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}
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}
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color *= vec4(COLOR_BOOST);
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color.a = 1.0;
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return clamp(GAMMA_OUT(color), 0.0, 1.0);
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}
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