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fteqw/engine/shaders/glsl/postproc_ascii.glsl

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!!cvardf r_glsl_ascii_mono=0
!!samps 1
//derived from https://www.shadertoy.com/view/lssGDj
#include "sys/defs.h"
varying vec2 texcoord;
#ifdef VERTEX_SHADER
void main()
{
texcoord = v_texcoord.xy;
texcoord.y = 1.0 - texcoord.y;
gl_Position = ftetransform();
}
#endif
#ifdef FRAGMENT_SHADER
uniform vec2 e_sourcesize;
float character(float n, vec2 p)
{
p = floor(p*vec2(4.0, -4.0) + 2.5);
if (clamp(p.x, 0.0, 4.0) == p.x && clamp(p.y, 0.0, 4.0) == p.y)
{
if (int(mod(n/exp2(p.x + 5.0*p.y), 2.0)) == 1) return 1.0;
}
return 0.0;
}
void main(void)
{
vec2 uv = floor(texcoord.xy * e_sourcesize); //in pixels.
vec3 col = texture2D(s_t0, (floor(uv/8.0)*8.0+4.0)/e_sourcesize.xy).rgb;
float gray = 0.3 * col.r + 0.59 * col.g + 0.11 * col.b;
if (r_glsl_ascii_mono != 0.0)
gray = gray = pow(gray, 0.7); //quake is just too dark otherwise.
else
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.
float n = 0.0; // space
if (gray > 0.1) n = 4096.0; // .
if (gray > 0.2) n = 65600.0; // :
if (gray > 0.3) n = 332772.0; // *
if (gray > 0.4) n = 15255086.0; // o
if (gray > 0.5) n = 23385164.0; // &
if (gray > 0.6) n = 15252014.0; // 8
if (gray > 0.7) n = 13199452.0; // @
if (gray > 0.8) n = 11512810.0; // #
vec2 p = mod(uv/4.0, 2.0) - vec2(1.0);
if (r_glsl_ascii_mono != 0.0)
col = vec3(character(n, p));
else
col = col*character(n, p); //note that this is kinda cheating.
gl_FragColor = vec4(col, 1.0);
}
#endif