<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style>
canvas {
border:1px solid
background-color:
}
</style>
</head>
<body onload="startGame()">
<script>
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
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
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>
<br>
<button onmousedown="accelerate(-0.2)" onmouseup="accelerate(0.05)">ACCELERATE</button>
<p>Use the ACCELERATE button to stay in the air</p>
<p>How long can you stay alive?</p>
</body>
</html>