Snippet Zone

Polar Plots

```
const Pnt = (x, y, p = { x, y }) => (
```

  p.add = o => (p.x += o.x, p.y += o.y, p), p

```
);
```

Pnt.polar = (rad, t) => Pnt(rad * Math.cos(t), rad * Math.sin(t));

```
 
```
```
const pnts = {};
```
```
let index = -1;
```
```
const polar = (inc, rad) => {
```
```
  index++;
```
```
  if (!pnts[index]) pnts[index] = 0;
```

  return Pnt.polar(rad, (pnts[index] += inc));

```
};
```
```
 
```
```
let d = document;
```
```
let b = d.body;
```
```
with (b.appendChild(
```

  Object.assign(d.createElement`canvas`, {

```
    width: 600,
```
```
    height: 500,
```
```
  })
```
```
).getContext`2d`) {
```
```
  canvas.style.transformOrigin = "0 0";
```
```
  canvas.style.transform = "scale(.6)";
```
```
 
```
```
  let p0 = Pnt(80, 100);
```
```
  let p1 = Pnt(270, 100);
```
```
  let p2 = Pnt(480, 40);
```
```
  let p3 = Pnt(170, 180);
```
```
  let p4 = Pnt(430, 300);
```
```
 
```
```
  fillStyle = "black";
```
```
 
```
```
  function loop() {
```
```
    for (let i = 0; i < 20; i++) {
```
```
      index = -1;
```
```
 
```

      p0.add(polar(0.2, 4).add(polar(-0.4, 2).add(polar(0.05, 1))));

```
      fillRect(p0.x, p0.y, 1, 1);
```
```
 
```
```
      p1.add(
```
```
        polar(0.1, 2).add(
```

          polar(-0.2, 2).add(polar(0.03, 1).add(polar(-0.01, 0.5)))

```
        )
```
```
      );
```
```
      fillRect(p1.x, p1.y, 1, 1);
```
```
 
```

      p2.add(polar(0.08, 3).add(polar(-0.2, -12).add(polar(2, 10))));

```
      fillRect(p2.x, p2.y, 1, 1);
```
```
 
```

      p3.add(polar(0.08, 7).add(polar(-0.2, -12).add(polar(2, 11))));

```
      fillRect(p3.x, p3.y, 1, 1);
```
```
 
```

      p4 = p4.add(polar(0.025, 2).add(polar(-0.05, 1)));

```
      fillRect(p4.x, p4.y, 1, 1);
```
```
    }
```
```
    requestAnimationFrame(loop);
```
```
  }
```
```
 
```
```
  loop();
```
```
}
```

Some polar plots…

December 29, 2021

// canvas // javascript // math // speed-coded // speedcoding

Confirm Background Color

```
const btn = document.body.appendChild(
```
```
  document.createElement('button')
```
```
)
```
```
btn.innerHTML = 'click me'
```
```
btn.style.fontSize = '2em'
```
```
btn.style.cursor = 'pointer'
```
```
btn.addEventListener('click', e => {
```

  if (confirm('Do you want to change the background color?')) {

```
    const deg = Math.random() * 360
```

    document.body.style.backgroundColor = `hsl(${deg}deg, 50%, 50%)`

```
  }
```
```
})
```

Change background color with a call to confirm

December 29, 2021

// javascript // ui

Plot Implicit Equation

```
let canvas = document.body.appendChild(
```

  Object.assign(document.createElement('canvas'), {

```
    width: 200,
```
```
    height: 200
```
```
  })
```
```
);
```
```
 
```
```
let c = canvas.getContext("2d"),
```

  pixels = c.createImageData(canvas.width, canvas.height),

```
  size = canvas.width * canvas.height,
```
```
  width = canvas.width,
```
```
  index = 0,
```
```
  x, y,
```
```
  a = 1,
```
```
  col,
```
```
  scale = 0.01;
```
```
 
```
```
for (var i = 0; i < size; i++) {
```
```
  x = i % width;
```
```
  y = parseInt(i / width);
```
```
  x -= 110;
```
```
  y -= 100;
```
```
  x *= scale;
```
```
  y *= scale;
```

  // http://www-history.mcs.st-and.ac.uk/Curves/Trifolium.html

  col = (x * x + y * y) * (y * y + x * (x + a));

```
 
```
```
  if (col >= 4 * a * x * y * y) {
```
```
    col = 155;
```
```
  }
```
```
 
```
```
  pixels.data[index++] = col;
```
```
  pixels.data[index++] = col;
```
```
  pixels.data[index++] = col;
```
```
  pixels.data[index++] = 255;
```
```
}
```
```
 
```
```
c.putImageData(pixels, 0, 0);
```

Plot an implicit equation on a canvas.

December 28, 2021

// canvas // javascript // math // tricks

Shorthand Primitives Golfing

```
!0 // true
```
```
 
```
```
!1 // false
```
```
 
```
```
1/0 // Infinity
```
```
 
```
```
0[0] // undefined (any digit works)
```

This is from user Isiah Meadows on the codegolf stackexchange…

December 27, 2021

// codegolf // javascript // speedcoding

WebGL Tangled Supershape Points

```
(() => {
```
```
  const TWO_PI = Math.PI * 2;
```
```
  const m = new Float32Array([
```
```
    0, 0, 0, 0,
```
```
    0, 0, 0, 0,
```
```
    0, 0, 0, 0,
```
```
    0, 0, 0, 0
```
```
  ])
```
```
 
```
```
 
```
```
  const vert = `
```
```
    attribute vec3 vec;
```
```
    uniform mat4 mat;
```
```
    void main(void) {
```

      gl_Position = mat * vec4(vec, 1.0);

```
      gl_PointSize = 2.0;
```
```
    }
```
```
  `
```
```
 
```
```
  const frag = `
```
```
    void main(void) {
```

      gl_FragColor = vec4(1., 1., 1., .25);

```
    }
```
```
  `
```
```
 
```

  document.body.style.background = '#232323'

```
  const gl = document.body
```

    .appendChild(document.createElement('canvas'))

```
    .getContext('webgl', {
```
```
      preserveDrawingBuffer: true,
```

      powerPreference: 'high-performance'

```
    })
```
```
 
```
```
  Object.assign(gl.canvas.style, {
```
```
    position: 'absolute',
```
```
    left: '50%',
```
```
    top: '50%',
```
```
    transform: 'translate(-50%, -50%)',
```
```
    outline: '1px solid gray'
```
```
  })
```
```
 
```
```
 
```
```
  with(gl) {
```
```
    const NUM = 120
```
```
    const radius = 0.7
```
```
    let verts = []
```
```
 
```
```
    // Superformula (equations from):
```

    // https://bsapubs.onlinelibrary.wiley.com/doi/10.3732/ajb.90.3.333

    // http://en.wikipedia.org/wiki/Superformula

    function superShape(a, b, m, n1, n2, n3, scale, x = 0, y = 0, z = 0) {

      const { random, pow, abs, cos, sin } = Math

      // with(Math) { // destrucuring vs the dreaded `with`

```
        let r = 0
```
```
        let p = 0
```
```
        let xp = 0
```
```
        let yp = 0
```
```
        let zp = 0
```
```
 
```
```
        let rotX = random() * TWO_PI
```
```
        let rotY = random() * TWO_PI
```
```
        let rotZ = random() * TWO_PI
```
```
 
```
```
        let cosX = cos(rotX)
```
```
        let cosY = cos(rotY)
```
```
        let sinX = sin(rotX)
```
```
        let sinY = sin(rotY)
```
```
 
```
```
        while (p <= TWO_PI) {
```
```
          let ang = (m * p) / 4
```
```
 
```

          r = pow(pow(abs(cos(ang) / a), n2) + pow(abs(sin(ang) / b), n3), -1 / n1)

```
          xp = r * cos(p)
```
```
          yp = r * sin(p)
```
```
 
```
```
          p += 0.05
```
```
 
```
```
          zp = zp * cosX - xp * sinX
```
```
          xp = zp * sinX + xp * cosX
```
```
          yp = yp * cosY - zp * sinY
```
```
          zp = yp * sinY + zp * cosY
```
```
 
```
```
          verts[inc] = xp * scale + x
```

          verts[inc + 1] = yp * scale + y

          verts[inc + 2] = zp * scale + z

```
          inc += 3;
```
```
        }
```
```
      // }
```
```
    }
```
```
 
```
```
    let inc = 0; 
```
```
    for (let i = 0; i < NUM; i++) {
```

      superShape(1, 1, 1 + ~~(Math.random() * 20),

```
        ~~(Math.random() * 30),
```
```
        ~~(Math.random() * 30),
```

        ~~(Math.random() * 30), Math.random() * .2,

```
        Math.random() - .5,
```
```
        Math.random() - .5,
```
```
        Math.random() - .5 )
```
```
    }
```
```
 
```
```
 
```
```
    console.log(verts.length)
```
```
    const overts = verts.concat()
```
```
    const leng = verts.length / 3
```
```
 
```

    bindBuffer(ARRAY_BUFFER, createBuffer())

    bufferData(ARRAY_BUFFER, new Float32Array(verts), STATIC_DRAW)

```
 
```

    const vs = createShader(VERTEX_SHADER)

```
    shaderSource(vs, vert)
```
```
    compileShader(vs)
```
```
 
```

    const fs = createShader(FRAGMENT_SHADER)

```
    const sp = createProgram()
```
```
 
```
```
    shaderSource(fs, frag)
```
```
    compileShader(fs)
```
```
    attachShader(sp, vs)
```
```
    attachShader(sp, fs)
```
```
    linkProgram(sp)
```
```
    useProgram(sp)
```
```
 
```

    const vec = getAttribLocation(sp, 'vec')

    vertexAttribPointer(vec, 3, FLOAT, false, 0, 0)

```
    enableVertexAttribArray(vec)
```
```
 
```

    const matLoc = getUniformLocation(sp, 'mat')

```
 
```
```
    function rot(x, y, z) {
```

      // https://wikimedia.org/api/rest_v1/media/math/render/svg/a8e16f4967571b7a572d1a19f3f6468512f9843e

```
 
```
```
      const sinA = Math.sin(x)
```
```
      const cosA = Math.cos(x)
```
```
      const sinB = Math.sin(y)
```
```
      const cosB = Math.cos(y)
```
```
      const sinY = Math.sin(z)
```
```
      const cosY = Math.cos(z)
```
```
 
```
```
      m[0] = cosA * cosB
```

      m[1] = cosA * sinB * sinY - sinA * cosY

      m[2] = cosA * sinB * cosY + sinA * sinY

```
      m[3] = 0
```
```
 
```
```
      m[4] = sinA * cosB
```

      m[5] = sinA * sinB * sinY + cosA * cosY

      m[6] = sinA * sinB * cosY - cosA * sinY

```
      m[7] = 0
```
```
 
```
```
      m[8] = -sinB
```
```
      m[9] = cosB * sinY
```
```
      m[10] = cosB * cosY
```
```
      m[11] = m[12] = m[13] = 0
```
```
      m[15] = 1
```
```
 
```

      uniformMatrix4fv(matLoc, false, m)

```
    }
```
```
 
```
```
    onresize = () => {
```
```
      const {
```
```
        canvas
```
```
      } = gl
```

      const size = Math.min(innerWidth, innerHeight) - 20

      canvas.width = canvas.height = size

```
      viewport(0, 0, size, size)
```
```
    }
```
```
 
```
```
    onresize()
```
```
 
```
```
    let rx = 0, ry = 0, rz = 0
```
```
 
```
```
    function loop() {
```
```
      rx += 0.01
```
```
      ry += 0.01
```
```
      rz += 0.01
```
```
      rot(rx, ry, rz)
```
```
 
```
```
      disable(DEPTH_TEST)
```
```
      enable(BLEND)
```

      blendFunc(SRC_ALPHA, ONE_MINUS_SRC_ALPHA)

```
      clearColor(0, 0, 0, 1)
```
```
      clear(COLOR_BUFFER_BIT)
```
```
      drawArrays(POINTS, 0, leng)
```

      window.requestAnimationFrame(loop)

```
    }
```
```
    loop()
```
```
  }
```
```
})()
```

An interesting accident while playing around with Supershapes and WebgGL points…

December 26, 2021

// animation // graphics // hacks // javascript // math // matrix // webgl

Older Posts

Newer Posts

Polar Plots

Confirm Background Color

Plot Implicit Equation

Shorthand Primitives Golfing

WebGL Tangled Supershape Points

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