slang-shaders/retro/shaders/ascii.slang

67 lines
1.6 KiB
Plaintext
Executable file

#version 450
// Bitmap to ASCII (not really) fragment shader by movAX13h, September 2013
// --- This shader is now used in Pixi JS ---
// Pixi JS is MIT-licensed
layout(push_constant) uniform Push
{
vec4 SourceSize;
vec4 OriginalSize;
vec4 OutputSize;
uint FrameCount;
} params;
layout(std140, set = 0, binding = 0) uniform UBO
{
mat4 MVP;
} global;
float character(float n, vec2 p) // some compilers have the word "char" reserved
{
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;
}
#pragma stage vertex
layout(location = 0) in vec4 Position;
layout(location = 1) in vec2 TexCoord;
layout(location = 0) out vec2 vTexCoord;
void main()
{
gl_Position = global.MVP * Position;
vTexCoord = TexCoord;
}
#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;
void main()
{
vec2 uv = vTexCoord * params.OutputSize.xy;
vec3 col = texture(Source, floor(uv/8.0)*8.0/params.OutputSize.xy).rgb;
float gray = dot(col.rgb, vec3(0.299, 0.587, 0.114));
float n = 65536.0; // .
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);
col = col*character(n, p);
FragColor = vec4(col, 1.0);
}