HTML5 canvas 小游戏练手

时间：2021-08-27 14:56:45

DEMO演示，请猛击

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
*{padding:0;margin:0;color:#fff;}
a {text-decoration:none;}
html,body{background-color:#000;}
#canvas{background-color:#001022;position:absolute;z-index:-1000;top:0}
#game{margin:auto;width:40%;background-color:#001022;}
#lay{width:100%;height:100%;position:relative}
#game p,h2{text-align:center;width:100%}
#gameInfo{position:relative;margin-top:150px;}

#gameState{margin-top:20px;margin-left:-400px;}
#reset{position:absolute;top:20px;text-decoration:none;margin-left:150px;}
#reset:hover{color:blue}
#play{width:80px;height:40px; font-weight:bold;font-size:25px;margin:10px}
h2{font-size:40px}
#footer{margin-top:120px;display:none}
#play {background: #CCC;color: #333;border-radius: 5px;}
</style>
</head>

<body>
<div id="game">
<p><a href="#" id="reset">Reset</a></p>
<a >太空保龄球</a>
<div id="lay">
<div id="gameUI">
<div id="gameInfo">
<p><h2>Space bowling</h2></p>
<p>This is an awesome game.</p>
<p><button id="play">Play</buttom>
</div>
<div id="gameState">
<p>Asteroids:<label id="bowlNum"></label></p>
<p>&nbsp;&nbsp; Clicks:<label id="ClickNum"></label></p>

</div>
<div id="footer">
<h2>You Win!</h2>
<p>Congratulations,you completed</p>
<p>the game in clicks</p>
<p>Play again</p>

</div>
</div>
</div>
<canvas id="canvas"></canvas>
</div>
</body>
</html>
<script type="text/javascript">

var bowlNum=0;
var clickNum=0;
var viewWidth = 0;
var viewHeight = 0;
try{
viewWidth=document.documentElement.clientWidth;
viewHeight = document.documentElement.clientHeight;
}catch(e){
viewWidth = document.body.clientWidth;
viewHeight = document.body.clientHeight;
}
var canvas = document.getElementById("canvas");
//canvas.width=546
canvas.height=viewHeight;
canvas.width=viewWidth/2.5;

var context = canvas.getContext("2d");
var play = document.getElementById("play");


play.onclick=function(){//开始游戏
document.getElementById("gameInfo").style.display="none";
document.getElementById("footer").style.display="none";
drawBegin();
}

//创建小球类
function bowling(x,y,radius,mass,firction){
this.x = x;
this.y=y;
this.radius = radius;
this.mass = mass;
this.firction=firction;
this.vX=0;
this.vY=0;
this.player=true;
this.R=10;
}
var bowlingArr = new Array();


function drawBegin(){
context.fillStyle="#646464";
context.beginPath();
context.arc(canvas.width/2,160,80,0,2*Math.PI,true);
context.closePath();
context.fill();

context.fillStyle="#fff";
context.beginPath();
context.arc(canvas.width/2,canvas.height-60,10,0,2*Math.PI,true);
var playBowling = new bowling(canvas.width/2,canvas.height-60,0,100,10);
bowlingArr.push(playBowling);
context.closePath();
context.fill();

var radius = 0;
//画若干小球在圆台上
for(var i=0;i<8;i++){
var x=canvas.width/2;
var y=100;
radius=Math.PI/4*(i);
x = Math.floor(x+Math.sin(radius)*60);
y = Math.floor(y+60-Math.cos(radius)*60);
var tempalBowling = new bowling(x,y,10,100,0.95);
tempalBowling.vX=0;
tempalBowling.vY=0;
bowlingArr.push(tempalBowling);
context.beginPath();
context.arc(x,y,10,0,Math.PI*2,true);
context.closePath();
context.fill();
}

var tempalBowling = new bowling(canvas.width/2,160,10,100,0.95);
tempalBowling.vX=0;
tempalBowling.vY=0;
bowlingArr.push(tempalBowling);
context.beginPath();
context.arc(canvas.width/2,160,10,0,Math.PI*2,true);
context.closePath();
context.fill();


radius = 0;
for(var i=0;i<5;i++){
var x=canvas.width/2;
var y=130;
radius=Math.PI*0.4*(i+1);
x = Math.floor(x+Math.sin(radius)*30);
y = Math.floor(y+30-Math.cos(radius)*30);
var tempalBowling = new bowling(x,y,10,100,0.95);
tempalBowling.vX=0;
tempalBowling.vY=0;
bowlingArr.push(tempalBowling);
context.beginPath();
context.arc(x,y,10,0,Math.PI*2,true);
context.closePath();
context.fill();
}

//画一个拖动圆台 描述允许拖动的范围

}


//刷新
function UpdateUI(){
context.clearRect(0,0,canvas.width,canvas.height);



context.fillStyle="#646464";
context.beginPath();
context.arc(canvas.width/2,canvas.height-60,10,0,Math.PI*2,false);
context.closePath();
context.fill();
//圆台
context.fillStyle="#646464";
context.beginPath();
context.arc(canvas.width/2,160,80,0,2*Math.PI,true);
context.closePath();
context.fill();
//15个小球
for(var i=0;i<bowlingArr.length;i++){
if(bowlingArr.player==false)
continue;
context.fillStyle="#ffffff";
context.beginPath();
context.arc(bowlingArr[i].x,bowlingArr[i].y,bowlingArr[i].R,0,Math.PI*2,false);
context.closePath();
context.fill();
if(bowlingArr[i].player==true)
bowlNum++;
}
//更新圆台上小球的数量
document.getElementById("bowlNum").innerHTML=bowlNum;
//更新点击释放小球的次数
document.getElementById("ClickNum").innerHTML = clickNum;
deleteBowling();

}
//删除小球 重置小球
function deleteBowling(){
for(var i=1;i<bowlingArr.length;i++){
if(bowlingArr[i].vX!=0||bowlingArr[i].vY!=0){
var dx=Math.abs(bowlingArr[i].x-canvas.width/2);
var dy=Math.abs(bowlingArr[i].y-160);
var distance = Math.floor(Math.sqrt(dx*dx+dy*dy));
if(distance>80){
bowlingArr[i].R-=0.5;
if(bowlingArr[i].R<=0)
bowlingArr[i].R=0;
bowlingArr[i].player=false;//不将其计入游戏了
}
}
}
//重置拖拽的小球
if(bowlingArr[0].x>canvas.width||bowlingArr[0].y<0||bowlingArr[0].y>canvas.height||bowlingArr[0].y<0){
bowlingArr[0].R=10;
bowlingArr[0].x=canvas.width/2;
bowlingArr[0].y=canvas.height-60;
bowlingArr[0].vX=0;
bowlingArr[0].vY=0;
}
}

//重置游戏
document.getElementById("reset").onclick = function(e){
var evt = e||window.event;
if(!!evt.preventDefualt){
evt.preventDefualt();
}
else{
evt.returnValue=false;
}
document.getElementById("gameInfo").style.display="block";
context.clearRect(0,0,canvas.width,canvas.height);
bowlingArr.length=0;
}



//小球动画
function animate(){
//bowlingArr[0].y-=bowlingArr[0].vy;
for(var i=0;i<bowlingArr.length;i++){
//碰撞检测 方法是两两比较，如果碰撞，能量转化
var tempalA = bowlingArr[i];
for(var j=i+1;j<bowlingArr.length;j++){
var tempalB=bowlingArr[j];
var dx = Math.abs(tempalB.x-tempalA.x);
var dy = Math.abs(tempalB.y-tempalA.y);
var distanceAB = Math.sqrt(dx*dx+dy*dy); //勾股定理

//检测碰撞
if(distanceAB<=tempalA.R+tempalB.R){
//碰了
var angle =Math.atan2(dy,dx);

var sine = Math.sin(angle);
var cosin = Math.cos(angle);

var x=0;
var y=0;

var xB=dx*cosin+dy*sine;
var yB=dy*cosin+dx*sine;

var vy=tempalA.vX*cosin+tempalA.vY*sine;
var vx=tempalA.vY*cosin+tempalA.vX*sine;

var vBX = tempalB.vX*cosin+tempalB.vY*sine;
var vBY = tempalB.vY*cosin+tempalB.vX*sine;

var xTotal = vx-vBX;
vX = ((tempalA.mass-tempalB.mass)*vx+2*tempalB.mass*vBX)/(tempalA.mass+tempalB.mass);
vBX = xTotal+vx;
vY = ((tempalA.mass-tempalB.mass)*vy+2*tempalB.mass*vBY)/(tempalA.mass+tempalB.mass);
vBY = xTotal+vy;

xB = x+(tempalA.radius+tempalB.radius);

tempalA.x = tempalA.x+(x*cosin-y*sine);
tempalA.y = tempalA.y+(y*cosin+x*sine);

tempalB.x = tempalB.x+(xB*cosin-yB*sine);
tempalB.y = tempalB.y+(yB*cosin+yB*sine);



tempalA.vX = vx*cosin - vy*sine;
tempalA.vY = vy*cosin + vx*sine;

tempalB.vX = vBX*cosin - vBY*sine;
tempalB.vY = vBY*cosin + vBY*sine;

}
}
bowlingArr[i].x+=bowlingArr[i].vX;
bowlingArr[i].y+=bowlingArr[i].vY;

}
UpdateUI();
setTimeout(arguments.callee,40);
}

//监听鼠标拖拽，释放小球
var moveAble=false;
var dragable=false;
var clickYN = false;
canvas.onmousedown = function(){
if(bowlingArr[0].y>=canvas.height-60)//必须在这个范围才能拖拽小球
clickYN=true;
}
canvas.onmousemove = function(e){
if(clickYN==true){
dragable=true;
}
if(dragable==true){

//计算拖动角度
bowlingArr[0].x = e.clientX-canvas.offsetLeft;
bowlingArr[0].y = e.clientY-canvas.offsetTop;
bowlingArr[0].vX = -(bowlingArr[0].x-canvas.width/2);
bowlingArr[0].vY = -(bowlingArr[0].y-canvas.height+60);
UpdateUI();
}
}
canvas.onmouseup = function(){
clickYN=false;
if(dragable==true){
clickNum++;//点击次数增加
dragable=false;
moveAble=true;

//开始游戏
if(moveAble)
animate();
}
}
</script>

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