w3schools game canvas

by Artem

HTML

<br>
<button id="acc">ACCELERATE</button>
<p>Use the ACCELERATE button to stay in the air</p>
<p>How long can you stay alive?</p>

CSS

canvas {
  border: 1px solid #d3d3d3;
  background-color: #f1f1f1;
}

JavaScript

var myGamePiece;
var myObstacles = [];
var myScore;

function startGame() {
  myGamePiece = new component(30, 30, "red", 10, 120);
  myGamePiece.gravity = 0.05;
  myScore = new component("30px", "Consolas", "black", 280, 40, "text");
  myGameArea.start();
}

var myGameArea = {
  canvas: document.createElement("canvas"),
  start: function() {
    this.canvas.width = 480;
    this.canvas.height = 270;
    this.context = this.canvas.getContext("2d");
    document.body.insertBefore(this.canvas, document.body.childNodes[0]);
    this.frameNo = 0;
    this.interval = setInterval(updateGameArea, 20);
  },
  clear: function() {
    this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
  }
}

function component(width, height, color, x, y, type) {
  this.type = type;
  this.score = 0;
  this.width = width;
  this.height = height;
  this.speedX = 0;
  this.speedY = 0;
  this.x = x;
  this.y = y;
  this.gravity = 0;
  this.gravitySpeed = 0;
  this.update = function() {
    ctx = myGameArea.context;
    if (this.type == "text") {
      ctx.font = this.width + " " + this.height;
      ctx.fillStyle = color;
      ctx.fillText(this.text, this.x, this.y);
    } else {
      ctx.fillStyle = color;
      ctx.fillRect(this.x, this.y, this.width, this.height);
    }
  }
  this.newPos = function() {
    this.gravitySpeed += this.gravity;
    this.x += this.speedX;
    this.y += this.speedY + this.gravitySpeed;
    this.hitBottom();
  }
  this.hitBottom = function() {
    var rockbottom = myGameArea.canvas.height - this.height;
    if (this.y > rockbottom) {
      this.y = rockbottom;
      this.gravitySpeed = 0;
    }
  }
  this.crashWith = function(otherobj) {
    var myleft = this.x;
    var myright = this.x + (this.width);
    var mytop = this.y;
    var mybottom = this.y + (this.height);
    var otherleft = otherobj.x;
    var otherright = otherobj.x + (otherobj.width);
    var othertop = otherobj.y;
    var otherbottom = otherobj.y + (otherobj.height);
    var...