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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Rotatio clone</title>
<script>
var W,H,R;
var cvs,ctx;
var fwd,speed,rot,podx,pody;
var walldir,walladv,wallspeed,wallgate;
//dir in [0..3] (0 right, 1 up etc)
//adv in pixels (distance the wall has advanced)
//gate in [0.0..1.0] (0 at start, 1 at end of line)
function init(){
W=480;
H=640;
R=15;
fwd=1;
speed=1;
rot=Math.random()*2*Math.PI;
podx=W/2;
pody=H/2;
walldir=0;
walladv=0;
wallspeed=1;
wallgate=0.5;
cvs=document.getElementById("cvs");
ctx=cvs.getContext("2d");
cvs.width=W;
cvs.height=H;
ctx.fillStyle="#fff";
ctx.beginPath();
ctx.rect(0,0,W,H);
ctx.fill();
// ctx.clearRect(0,0,W,H);
document.addEventListener("keydown",keydown);
document.addEventListener("keyup",keyup);
document.addEventListener("mousedown",keydown);
document.addEventListener("mouseup",keyup);
runloop();
}
function runloop(){
var id=requestAnimationFrame(runloop);
increment();
draw();
if(checks()){
cancelAnimationFrame(id);
}
}
function draw(){
ctx.clearRect(0,0,W,H);
ctx.strokeStyle="#000";
ctx.lineWidth=4;
var d=Math.sqrt(W*W+H*H),dx=d*Math.cos(rot),dy=d*Math.sin(rot);
ctx.beginPath();
ctx.moveTo(-dx+podx,-dy+pody);
ctx.lineTo(dx+podx,dy+pody);
ctx.stroke();
ctx.beginPath();
ctx.arc(podx,pody,R,0,2*Math.PI,true);
ctx.stroke();
var wall2pos=function(perc){
switch(walldir){
case 0: return [walladv,perc*H];
case 1: return [perc*W,H-1-walladv];
case 2: return [W-1-walladv,perc*H];
case 3: return [perc*W,walladv];
}
};
var p0=wall2pos(0),pgate1=wall2pos(wallgate-.1),pgate2=wall2pos(wallgate+.1),p1=wall2pos(1);
ctx.beginPath();
ctx.moveTo(p0[0],p0[1]);
ctx.lineTo(pgate1[0],pgate1[1]);
ctx.moveTo(pgate2[0],pgate2[1]);
ctx.lineTo(p1[0],p1[1]);
ctx.stroke();
}
function increment(){
rot+=0.015;
podx+=Math.cos(rot)*fwd*speed*2.5;
pody+=Math.sin(rot)*fwd*speed*2.5;
walladv+=wallspeed;
}
function checks(){
if(checklose()){
alert("You lost!");
return true;
}
}
function checklose(){
if(podx-R<=0||podx+R>=W-1||pody-R<=0||pody+R>=H-1)return true;
switch(walldir){
case 0: if(abs(walladv- podx)<R+4)return true; break;
case 1: if(abs(walladv-H+pody)<R+4)return true; break;
case 2: if(abs(walladv-W+podx)<R+4)return true; break;
case 3: if(abs(walladv- pody)<R+4)return true; break;
}
return false;
}
function keydown(ev){
fwd=-1;
}
function keyup(ev){
fwd=1;
}
function modb(v,m){ //modbound
if(v<0)return m-(-v%m);
if(v>=m)return v%m;
}
//shim
var requestAnimationFrame=requestAnimationFrame||webkitRequestAnimationFrame||function(c){return setTimeout(c,1000/60);};
var cancelAnimationFrame=cancelAnimationFrame||webkitCancelAnimationFrame||webkitCancelRequestAnimationFrame||function(i){return clearTimeout(i);};
window.addEventListener("load",init);
</script>
<style>
body{
background-color:#eee;
}
canvas#cvs{
border-radius:4px;
background-color:#fff;
}
</style>
</head>
<body>
<div style="text-align:center">
<canvas id="cvs"></canvas>
</div>
</body>
</html>
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