Example 1: how to draw a flower in javascript
const ctx = canvas.getContext("2d");
const petal = [
[
[0, 0],
[0.3, -1],
[0.7, -1],
[1, 0],
[0.7, 1],
[0.3, 1],
[0, 0]
],
[
[0, 0],
[1, 0]
],
];
function drawPetal(path, width, height) {
var i = 0;
do {
const p = path[i];
let j = 0;
ctx.moveTo(p[j][0] * width, p[j++][1] * height);
while (j < p.length - 1) {
ctx.lineTo(p[j][0] * width, p[j++][1] * height);
}
if (p[j][0] === p[0][0] && p[j][1] === p[0][1]) {
ctx.closePath();
} else {
ctx.lineTo(p[j][0] * width, p[j][1] * height)
}
} while (++i < path.length);
}
function drawPetals(x, y, count, startAt, petal, width, height) {
const step = (Math.PI * 2) / count;
ctx.setTransform(1, 0, 0, 1, x, y);
ctx.rotate(startAt);
for (var i = 0; i < count; i += 1) {
drawPetal(petal, width, height);
ctx.rotate(step);
}
ctx.setTransform(1, 0, 0, 1, 0, 0);
}
function drawFlower(col, lineWidth, fitScale, petalCount) {
ctx.strokeStyle = col;
ctx.lineWidth = lineWidth;
const size = Math.min(ctx.canvas.width, ctx.canvas.height) * fitScale * 0.5;
ctx.beginPath();
drawPetals(ctx.canvas.width / 2, ctx.canvas.height / 2, 5, -Math.PI / 2, petal, size, size * 0.2);
ctx.stroke();
ctx.beginPath();
ctx.arc(ctx.canvas.width / 2, ctx.canvas.height / 2, size * 0.15, 0, Math.PI * 2);
ctx.fillStyle = col;
ctx.fill();
}
drawFlower("black", 4, 0.95, 5);
Example 2: make dots in three js
var dotGeometry = new THREE.Geometry();
dotGeometry.vertices.push(new THREE.Vector3( 0, 0, 0));
var dotMaterial = new THREE.PointsMaterial( { size: 1, sizeAttenuation: false } );
var dot = new THREE.Points( dotGeometry, dotMaterial );
scene.add( dot );