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 crash = true;
if ((mybottom < othertop) || (mytop > otherbottom) || (myright < otherleft) || (myleft > otherright)) {
crash = false;
}
return crash;
}
}
function updateGameArea() { var x, height, gap, minHeight, maxHeight, minGap, maxGap; for (i = 0; i < myObstacles.length; i += 1) { if (myGamePiece.crashWith(myObstacles[i])) { return; } } myGameArea.clear(); myGameArea.frameNo += 1; if (myGameArea.frameNo == 1 || everyinterval(150)) { x = myGameArea.canvas.width; minHeight = 20; maxHeight = 200; height = Math.floor(Math.random()(maxHeight-minHeight+1)+minHeight); minGap = 50; maxGap = 200; gap = Math.floor(Math.random()(maxGap-minGap+1)+minGap); myObstacles.push(new component(10, height, "green", x, 0)); myObstacles.push(new component(10, x - height - gap, "green", x, height + gap)); } for (i = 0; i < myObstacles.length; i += 1) { myObstacles[i].x += -1; myObstacles[i].update(); } myScore.text="SCORE: " + myGameArea.frameNo; myScore.update(); myGamePiece.newPos(); myGamePiece.update(); }
function everyinterval(n) { if ((myGameArea.frameNo / n) % 1 == 0) {return true;} return false; }
function accelerate(n) {
myGamePiece.gravity = n;
}
</script>
ACCELERATE
Use the ACCELERATE button to stay in the air
How long can you stay alive?