73 lines
1.8 KiB
JavaScript
73 lines
1.8 KiB
JavaScript
'use strict';
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class Vector{
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constructor(x, y){
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this.x = x;
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this.y = y;
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}
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scalarProduct(other){
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return this.x*other.x + this.y*other.y;
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}
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magnitude(){
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return Math.sqrt(this.x**2 + this.y**2);
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}
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//vector product would be useless because the resultant would be in the z-axis
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angle(other = new Vector(1, 0)){ //need some magnitude for origin vector to avoid division by 0
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//cosθ = a.b/|a||b|
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return Math.acos(this.scalarProduct(other)/(this.magnitude()*other.magnitude()));
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}
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//figuring out coordinates from angle and distance
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positionFromAngle(angle, distance){
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return new Vector((this.x + distance) * Math.cos(angle), (this.y+distance)*Math.sin(angle));
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}
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}
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class Asteroid{
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//FIXME: Asteroid generation is very wonky
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constructor(size, position, edges=5){
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this.size = size;
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this.edges = edges;
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this.position = position;
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this.nodes = [this.position];
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for(let i=0; i<this.edges; i++){
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let pos = this.nodes[i].positionFromAngle( this.nodes[i].angle() + (Math.max(Math.PI/6, Math.random()*(Math.PI/3))), 5);
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this.nodes.push(pos);
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}
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}
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draw(ctx){
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ctx.beginPath();
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this.nodes.forEach((node, _) => {
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ctx.lineTo(node.x,node.y);
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})
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ctx.closePath();
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ctx.stroke();
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}
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}
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//initializing canvas
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const canvas = document.getElementById("canvas");
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canvas.width = window.innerWidth;
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canvas.height = window.innerHeight;
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const ctx = canvas.getContext("2d");
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const asteroid = new Asteroid(50, new Vector(300, 240));
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function animate(){
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requestAnimationFrame(animate);
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ctx.clearRect(0, 0, canvas.width, canvas.height);
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asteroid.draw(ctx);
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}
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animate();
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