glsl-imager
Enjoy GLSL shaders from the comfort of your terminal!
Or, save output as a JPG, GIF, PNG, or PPM file.
renderToConsole(width,height,vertexSrc,fragmentSrc);
renderToFile("filename.jpg",width,height,vertexSrc,fragmentSrc);
Table of Contents
Installation
npm i glsl-imagerUsage
Mandelbrot shader example. Shaders originally from headless-gl
Warning - renderToConsole should be used for low resolutions only -- if you want to render regular size images, use renderToFile
var width = 64.0
var height = 64.0
var vertexSrc = `
attribute vec2 a_position;
void main() {
gl_Position = vec4(a_position,0,1);
}
`
var fragmentSrc = `
precision mediump float;
const int max_iterations = 255;
const float width = ${width.toFixed(1)};
const float height = ${height.toFixed(1)};
vec2 complex_square( vec2 v ) {
return vec2(
v.x * v.x - v.y * v.y,
v.x * v.y * 2.0
);
}
void main()
{
vec2 uv = gl_FragCoord.xy - vec2(width,height) * 0.5;
uv *= 2.5 / min( width, height );
#if 0 // Mandelbrot
vec2 c = uv;
vec2 v = vec2( 0.0 );
float scale = 0.06;
#else // Julia
vec2 c = vec2( 0.285, 0.01 );
vec2 v = uv;
float scale = 0.01;
#endif
int count = max_iterations;
for ( int i = 0 ; i < max_iterations; i++ ) {
v = c + complex_square( v );
if ( dot( v, v ) > 4.0 ) {
count = i;
break;
}
}
gl_FragColor = vec4( float( count ) * scale );
}
`
var renderer = require('glsl-imager');
renderer.renderToConsole(width,height,vertexSrc,fragmentSrc);
//or, save directly to file...
//renderer.renderToFile("test_ppm.ppm",width,height,vertexSrc,fragmentSrc);
//renderer.renderToFile("test_png.png",width,height,vertexSrc,fragmentSrc);
//renderer.renderToFile("test_jpg.jpg",width,height,vertexSrc,fragmentSrc);
//renderer.renderToFile("test_gif.gif",width,height,vertexSrc,fragmentSrc);
//alternatively, get+save raw pixel data...
//var pixelDataRaw = renderer.render(width,height,vertexSrc,fragmentSrc);
//renderer.savePixelsToFile("test_png2.png",pixelDataRaw,width,height);Result