h5的游戏开发详解

//ball 球function Ball(sx, sy, rad, stylestring) {    this.sx = sx;    this.sy = sy;    this.rad = rad;    this.draw = drawball;    this.moveit = moveball;    this.fillstyle = stylestring;

}function drawball() {

    ctx.fillStyle = this.fillstyle;

    ctx.beginPath();    //ctx.fillStyle= rgb(0,0,0);

    ctx.arc(this.sx, this.sy, this.rad, 0, Math.PI * 2, true);

    ctx.fill();

}function moveball(dx, dy) {    this.sx += dx;    this.sy += dy;

}//Rect 方形function Myrectangle(sx, sy, swidth, sheight, stylestring) {    this.sx = sx;    this.sy = sy;    this.swidth = swidth;    this.sheight = sheight;    this.fillstyle = stylestring;    this.draw = drawrects;    this.moveit = moveball;//move方法是一样的}function drawrects() {

    ctx.fillStyle = this.fillstyle;

    ctx.fillRect(this.sx, this.sy, this.swidth, this.sheight);

}//多边形function Polycard(sx, sy, rad, n, frontbgcolor, backcolor, polycolor) {    this.sx = sx;    this.sy = sy;    this.rad = rad;    this.draw = drawpoly;    this.frontbgcolor = frontbgcolor;    this.backcolor = backcolor;    this.polycolor = polycolor;    this.n = n;    this.angle = (2 * Math.PI) / n;  //parens may not be needed.

    this.moveit = generalmove;

}//画多边形function drawpoly() {

    ctx.fillStyle = this.frontbgcolor;

    ctx.strokeStyle = this.backcolor;

    ctx.fillRect(this.sx - 2 * this.rad, this.sy - 2 * this.rad, 4 * this.rad, 4 * this.rad);

    ctx.beginPath();

    ctx.fillStyle = this.polycolor;    var i;    var rad = this.rad;

    ctx.beginPath();

    ctx.moveTo(this.sx + rad * Math.cos(-.5 * this.angle), this.sy + rad * Math.sin(-.5 * this.angle));    for (i = 1; i < this.n; i++) {

        ctx.lineTo(this.sx + rad * Math.cos((i - .5) * this.angle), this.sy + rad * Math.sin((i - .5) * this.angle));

    }

    ctx.fill();

}function generalmove(dx, dy) {    this.sx += dx;    this.sy += dy;

}//图像function Picture(sx, sy, swidth, sheight, imga) {    this.sx = sx;    this.sy = sy;    this.img = imga;    this.swidth = swidth;    this.sheight = sheight;    this.draw = drawAnImage;

}function drawAnImage() {

    ctx.drawImage(this.img, this.sx, this.sy, this.swidth, this.sheight);

}

(ev.layerX || ev.layerX == 0) {

       mx ==  (ev.offsetX || ev.offsetX == 0) {

       mx ==