Created
January 31, 2020 09:29
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moving ball
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| class Ball { | |
| constructor(x, y) { | |
| this.pos = new Vector(x, y); | |
| this.r = 10; | |
| this.vel = new Vector(10, 3); | |
| this.forces = []; | |
| } | |
| draw(ctx) { | |
| ctx.save(); | |
| ctx.beginPath(); | |
| ctx.arc(this.pos.x, this.pos.y, this.r, 0, Math.PI * 2); | |
| ctx.fillStyle = 'blue'; | |
| ctx.fill(); | |
| ctx.restore(); | |
| } | |
| move() { | |
| this.forces.forEach(force => this.vel.add(force)); | |
| this.pos.add(this.vel); | |
| if (this.pos.x >= w - this.r && this.vel.x <= 0) this.pos.x = w - this.r; | |
| if (this.pos.y >= h - this.r && this.vel.y <= 0) this.pos.y = h - this.r; | |
| if (this.pos.x < 0 || this.pos.x > w - this.r) this.vel.x *= -1; | |
| if (this.pos.y < 0 || this.pos.y > h - this.r) this.vel.y *= -1; | |
| // Friction. | |
| if (this.pos.y === h - this.r) { | |
| if (this.vel.x > 0) { | |
| this.vel.add(new Vector(-0.1, 0)); | |
| } else { | |
| this.vel.add(new Vector(0.1, 0)); | |
| } | |
| } | |
| } | |
| applyForce(force) { | |
| this.forces = [...this.forces, force]; | |
| } | |
| startOver() { | |
| this.pos.x = random(0, w); | |
| this.pos.y = random(0, 100); | |
| this.vel = new Vector(10, 3); | |
| } | |
| } |
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <title>Ball</title> | |
| </head> | |
| <body> | |
| <canvas id="canvas" width="700" height="400"></canvas> | |
| <script type="text/javascript" src="tool.js"></script> | |
| <script type="text/javascript" src="vector.js"></script> | |
| <script type="text/javascript" src="ball.js"></script> | |
| <script type="text/javascript" src="script.js"></script> | |
| </body> | |
| </html> |
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| let c, ctx, w, h; | |
| let ball; | |
| let gravity; | |
| function setup() { | |
| c = document.querySelector('#canvas'); | |
| ctx = c.getContext('2d'); | |
| w = c.width; | |
| h = c.height; | |
| ball = new Ball(random(0, w), random(0, 100)); | |
| gravity = new Vector(0, 1); | |
| ball.applyForce(gravity); | |
| c.onclick = () => ball.startOver(); | |
| } | |
| function draw() { | |
| ctx.fillStyle = 'lightgray'; | |
| ctx.fillRect(0, 0, w, h); | |
| ball.draw(ctx); | |
| ball.move(); | |
| window.requestAnimationFrame(draw); | |
| } | |
| setup(); | |
| window.requestAnimationFrame(draw); |
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| function random(min, max) { | |
| min = Math.ceil(min); | |
| max = Math.floor(max); | |
| return Math.floor(Math.random() * (max - min + 1)) + min; //The maximum is inclusive and the minimum is inclusive | |
| } |
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| class Vector { | |
| constructor(x, y) { | |
| this.x = x; | |
| this.y = y; | |
| } | |
| add(vec) { | |
| this.x += vec.x; | |
| this.y += vec.y; | |
| } | |
| } |
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