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` ````
<canvas id="canv"></canvas>
```

` ````
body {
margin: 0;
}
canvas {
display: block;
width: 100vw;
height: 100vh;
}
```

` ````
import GLea from 'https://terabaud.github.io/glea/dist/glea.js';
// this is just for code highlighting in VSCode
// via the glsl-literal extension
const glsl = x => x;
const frag = glsl`
precision highp float;
uniform float time;
uniform float width;
uniform float height;
const float PI = 3.141592654;
const float DEG = PI / 180.0;
vec2 coords() {
float vmin = min(width, height);
return vec2((gl_FragCoord.x - width * .5) / vmin,
(gl_FragCoord.y - height * .5) / vmin);
}
vec2 rotate(vec2 p, float a) {
return vec2(p.x * cos(a) - p.y * sin(a),
p.x * sin(a) + p.y * cos(a));
}
vec2 repeat(in vec2 p, in vec2 c) {
return mod(p, c) - 0.5 * c;
}
// Distance functions by Inigo Quilez
// https://iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm
float circle(in vec2 p, float radius) {
return length(p) - radius;
}
float pie( in vec2 p, in vec2 c, in float r )
{
p.x = abs(p.x);
float l = length(p) - r;
float m = length(p-c*clamp(dot(p,c),0.0,r)); // c = sin/cos of the aperture
return max(l,m*sign(c.y*p.x-c.x*p.y));
}
// function from https://www.shadertoy.com/view/3ll3zr
float sdHeart(in vec2 p, float s) {
p /= s;
vec2 q = p;
q.x *= 0.5 + .5 * q.y;
q.y -= abs(p.x) * .63;
return (length(q) - .7) * s;
}
float symmetricDiff(float a, float b)
{
// (A ∪ B) \ (A ∩ B)
return max(min(a, b), -max(a, b));
}
float subtract(float a, float b)
{
return max(-a, b);
}
vec3 shade(in vec2 p)
{
vec3 background = vec3(.2 + sin(time * .1) * .2, .1, .2);
vec3 foreground = vec3(.5 + .5 * sin(.015 + time * .1), .2 + p.y * .01, .9);
vec2 h = vec2(sin(90.0 * 3.14/180.0), cos(90.0 * 3.14/180.0));
float sdf0 = circle(p, 50.0);
sdf0 = subtract(circle(p, 40.0), sdf0);
float sdf = mix(sdf0, sdHeart(p + vec2(0, 2.0 +sin(time) * 4.0), 40.0), clamp(2.0 * sin(time * .1), 0.0, 1.0));
if (sdf > 0.0 && sdf < 1.0) {
// anti alias
return mix(background, foreground, sqrt(1.0 - sdf));
}
if (sdf < 0.0) {
return foreground;
}
float sdf2 = circle(p, 50.0);
vec3 col = sdf2 < 0.0 ? vec3(0) : background;
// Darken around surface
col = mix(col, col*1.0-exp(-2.0 * abs(min(sdf, sdf2))), 0.4);
// repeating lines
return col;
}
void main () {
float rota2 = 45. * DEG;
float zoom2 = .33;
vec2 p0 = repeat(rotate(coords() * zoom2, rota2), vec2(.125));
float zoom = 900.0;
float rota = mix(mod(time * .1, 2.0 * PI), 0.0, clamp(2.0 * sin(time * .1), 0.0, 1.0));
vec2 p1 = rotate(p0 * zoom, rota - rota2);
vec3 col = shade(p1);
gl_FragColor = vec4(col, 1.0);
}
`
const vert = glsl`
precision mediump float;
attribute vec2 position;
void main () {
gl_Position = vec4(position, 0, 1.0);
}
`;
const glea = new GLea({
shaders: [
GLea.fragmentShader(frag),
GLea.vertexShader(vert)
],
buffers: {
position: GLea.buffer(2, [1, 1, -1, 1, 1,-1, -1,-1])
}
}).create();
function loop(time) {
const { gl } = glea;
glea.clear();
glea.uni('width', glea.width);
glea.uni('height', glea.height);
glea.uni('time', time * .005);
gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
requestAnimationFrame(loop);
}
function setup() {
const { gl } = glea;
window.addEventListener('resize', () => {
glea.resize();
});
loop(0);
}
setup();
```

999px

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