时间:2021-07-01 10:21:17 帮助过:8人阅读
桌球游戏
整个桌球游戏就两个类,一个是球,一个是辅助瞄准线。如果想把改游戏弄的更复杂,还可以再抽象一个形状类,用于检测球与边角的碰撞以及进球。我做的这个游戏采取了最简单的墙壁碰撞检测,所以没有进行球与不规则形状的碰撞检测,如果想玩更复杂的碰撞,可以戳 关于简单的碰撞检测 岑安大大讲的还是很好的。好,接下来就一步一步来:
【球】
先贴代码:
[/code]var Ball = function(x , y , ismine){
this.x = x;
this.y = y;
this.ismine = ismine;
this.oldx = x;
this.oldy = y;
this.vx = 0;
this.vy = 0;
this.radius = ballRadius;
this.inhole = false;this.moving = true;
}
Ball.prototype = {
constructor:Ball,
_paint:function(){
var b = this.ismine?document.getElementById("wb") : document.getElementById("yb")
if(b.complete) {
ctx.drawImage(b , this.x-this.radius , this.y-this.radius , 2*this.radius , 2*this.radius);
}
else {
b.onload = function(){
ctx.drawImage(b , this.x-this.radius , this.y-this.radius , 2*this.radius , 2*this.radius);
}
}
},
_run:function(t){
this.oldx = this.x;
this.oldy = this.y;
this.vx = Math.abs(this.vx)<0.1? 0 : (this.vx>0? this.vx-mcl*t : this.vx+mcl*t);
this.vy = Math.abs(this.vy)<0.1? 0 : (this.vy>0? this.vy-mcl*t : this.vy+mcl*t);
// this.vx += this.vx>0? -mcl*t : mcl*t;
// this.vy += this.vy>0? -mcl*t : mcl*t;
this.x += t * this.vx * pxpm;
this.y += t * this.vy * pxpm;
if((this.x<50 && this.y<50) || (this.x>370 && this.x<430 && this.y<50) || (this.x > 758 && this.y<50) || (this.x<46 && this.y>490) || (this.x>377 && this.x<420 && this.y>490) || (this.x > 758 && this.y>490)){
this.inhole = true;
if(this.ismine){
var that = this;
setTimeout(function(){
that.x = 202;
that.y = canvas.height/2;
that.vx = 0;
that.vy = 0;
that.inhole = false;
} , 500)
}
else {
document.getElementById("shotNum").innerHTML = parseInt(document.getElementById("shotNum").innerHTML)+1
}
}
else {
if(this.y > canvas.height - (ballRadius+tbw) || this.y < (ballRadius+tbw)){
this.y = this.y < (ballRadius+tbw) ? (ballRadius+tbw) : (canvas.height - (ballRadius+tbw));
this.derectionY = !this.derectionY;
this.vy = -this.vy*0.6;
}
if(this.x > canvas.width - (ballRadius+tbw) || this.x < (ballRadius+tbw)){
this.x = this.x < (ballRadius+tbw) ? (ballRadius+tbw) : (canvas.width - (ballRadius+tbw));
this.derectionX = !this.derectionX;
this.vx = -this.vx*0.6;
}
}
this._paint();
if(Math.abs(this.vx)<0.1 && Math.abs(this.vy)<0.1){
this.moving = false;
}
else {
this.moving = true;
}
}
}[/code]
球类的属性:x,y球的位置,vx,vy球的水平速度以及求得垂直速度,ismine代表是白球还是其他球(不同球在_paint方法中绘制的图片不一样),oldx,oldy用于保存球的上一帧位置,不过暂时还没用上,应该有用吧。_paint方法没什么好说的,_run方法就是跟踪小球位置,根据小球每一帧的时间来算出小球的位移增量以及速度增量,mcl和pxpm都是常量,mcl是摩擦力,pxpm是大概算个像素和现实转换比例。。。。然后就是碰撞检测,这个很容易理解了,就计算小球的位置有没有超过边界,超过了就反弹。不过这种碰撞检测很不严谨,如果真要做游戏建议用更复杂一些的。还有就是根据小球的速度来让小球静止。
【多球碰撞检测】
将速度增量赋给碰撞小球。因为两个球碰撞那一帧,两个球是有部分重叠的,所以得进行位置修正,不然小球会一直处于碰撞然后就黏在一起了,位置修正的原理也简单,算出两球的球心距离,通过勾股定理计算出两球的重叠区域的宽度,然后把宽度除于2后赋给小球新的位置,新的位置就是两个球的半径刚好等于球心距。
【鼠标动作】
document.querySelector(".shotPower").style.display = "block";
document.querySelector(".shotPower").style.top = balls[0].y-60 + "px";
document.querySelector(".shotPower").style.left = balls[0].x-40 +"px";
document.getElementById("pow").className = "animate";
var x = event.clientX + document.body.scrollLeft + document.documentElement.scrollLeft - document.querySelector(".view").offsetLeft;
var y = event.clientY + document.body.scrollTop + document.documentElement.scrollTop - document.querySelector(".view").offsetTop;
dotline.display = true;
dotline.x0 = balls[0].x;
dotline.y0 = balls[0].y;
dotline.x1 = x;
dotline.y1 = y;
window.addEventListener("mouseup" , muHandle , false);
window.addEventListener("mousemove" , mmHandle , false);
function mmHandle(){
var x = event.clientX + document.body.scrollLeft + document.documentElement.scrollLeft - document.querySelector(".view").offsetLeft;
var y = event.clientY + document.body.scrollTop + document.documentElement.scrollTop - document.querySelector(".view").offsetTop;
dotline.x1 = x;
dotline.y1 = y;
}
function muHandle(){
var x = event.clientX + document.body.scrollLeft + document.documentElement.scrollLeft - document.querySelector(".view").offsetLeft;
var y = event.clientY + document.body.scrollTop + document.documentElement.scrollTop - document.querySelector(".view").offsetTop;
var angle = Math.atan((y - balls[0].y)/(x - balls[0].x));
var h = document.getElementById("pow").offsetHeight/document.getElementById("powbar").offsetHeight;
var v = 60*h;
document.getElementById("pow").style.height = h*100+"%"
balls[0].vx = x - balls[0].x>0 ? v*Math.abs(Math.cos(angle)) : -v*Math.abs(Math.cos(angle));
balls[0].vy = y - balls[0].y>0 ? v*Math.abs(Math.sin(angle)) : -v*Math.abs(Math.sin(angle));
document.getElementById("pow").className = "";
window.removeEventListener("mouseup" , muHandle , false);
window.removeEventListener("mousemove" , muHandle , false);
dotline.display = false;
document.querySelector(".shotPower").style.display = "none";
}
},false);
【动画舞台】
collision();
balls.foreach(function(){
if(!this.inhole) this._run(t);
});
if(dotline.display){
dotline.x0 = balls[0].x;
dotline.y0 = balls[0].y;
dotline._paint();
}
t0 = t1;
if(!animateStop){
if("requestAnimationFrame" in window){
requestAnimationFrame(animate);
}
else if("webkitRequestAnimationFrame" in window){
webkitRequestAnimationFrame(animate);
}
else if("msRequestAnimationFrame" in window){
msRequestAnimationFrame(animate);
}
else if("mozRequestAnimationFrame" in window){
mozRequestAnimationFrame(animate);
}
else {
setTimeout(animate , 16);
}
}
}
window.onload = function(){
var myball = new Ball(202 , canvas.height/2 , true);
balls.push(myball);
for(var i=0;i<6;i++){
for(var j=0;j var other = new Ball(520+i*(ballRadius-2)*2 , (canvas.height-i*2*ballRadius)/2+ballRadius+2*ballRadius*j , false);
balls.push(other);
}
}
t0 = new Date();
dotline = new dotLine(0,0,0,0);
animateStop = false;
animate();
}
源码地址:https://github.com/whxaxes/canvas-test/tree/gh-pages/src/Game-demo/snooker