60 lines
1.6 KiB
GLSL
60 lines
1.6 KiB
GLSL
!!cvardf r_glsl_ascii_mono=0
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!!samps screen=0
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//derived from https://www.shadertoy.com/view/lssGDj
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#include "sys/defs.h"
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varying vec2 texcoord;
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#ifdef VERTEX_SHADER
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void main()
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{
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texcoord = v_texcoord.xy;
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texcoord.y = 1.0 - texcoord.y;
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gl_Position = ftetransform();
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}
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#endif
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#ifdef FRAGMENT_SHADER
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uniform vec2 e_sourcesize;
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float character(float n, vec2 p)
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{
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p = floor(p*vec2(4.0, -4.0) + 2.5);
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if (clamp(p.x, 0.0, 4.0) == p.x && clamp(p.y, 0.0, 4.0) == p.y)
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{
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if (int(mod(n/exp2(p.x + 5.0*p.y), 2.0)) == 1) return 1.0;
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}
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return 0.0;
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}
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void main(void)
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{
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vec2 uv = floor(texcoord.xy * e_sourcesize); //in pixels.
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vec3 col = texture2D(s_screen, (floor(uv/8.0)*8.0+4.0)/e_sourcesize.xy).rgb;
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float gray = 0.3 * col.r + 0.59 * col.g + 0.11 * col.b;
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if (r_glsl_ascii_mono != 0.0)
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gray = gray = pow(gray, 0.7); //quake is just too dark otherwise.
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else
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gray = gray = pow(gray, 0.45); //col*char is FAR too dark otherwise, and much of the colour will come from the col term anyway.
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float n = 0.0; // space
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if (gray > 0.1) n = 4096.0; // .
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if (gray > 0.2) n = 65600.0; // :
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if (gray > 0.3) n = 332772.0; // *
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if (gray > 0.4) n = 15255086.0; // o
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if (gray > 0.5) n = 23385164.0; // &
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if (gray > 0.6) n = 15252014.0; // 8
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if (gray > 0.7) n = 13199452.0; // @
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if (gray > 0.8) n = 11512810.0; // #
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vec2 p = mod(uv/4.0, 2.0) - vec2(1.0);
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if (r_glsl_ascii_mono != 0.0)
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col = vec3(character(n, p));
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else
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col = col*character(n, p); //note that this is kinda cheating.
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gl_FragColor = vec4(col, 1.0);
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}
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#endif
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