从零开始手把手教你使用javascript+canvas开发一个塔防游戏07塔的升级和出售

//画出塔的攻击范围以及升级等信息
    drawScope : function(tower){
        var select = Game.canvasList.select;
        Canvas.clear(select,500,500);
        Canvas.fillArc(select,tower.x+25,tower.y+25,TowerType[tower.type]["level_"+tower.level].scope,"rgba(25,174,70,0.5)");
        if(tower.level < 3)Canvas.drawImg(select,Game.imgList.btn_img,0,0,20,20,tower.x,tower.y,20,20);
        Canvas.drawImg(select,Game.imgList.btn_img,20,0,20,20,tower.x+30,tower.y+30,20,20);
    },
    //升级或卖掉
    upgradeOrSell : function(x,y){
        var tower = Game.nowSelectTower;
        //升级
        if(tower.level < 3 && T.pointInRect({x:x,y:y},{x:tower.x,y:tower.y,width:20,height:20})){
            if(this.score - TowerType[tower.type]["level_"+(tower.level+1)].buyIt < 0)return false;
            tower.level += 1;
            this.updateScore(TowerType[tower.type]["level_"+tower.level].buyIt * -1);
            this.drawScope(tower);
            //update
        }
        //卖掉
        else if(T.pointInRect({x:x,y:y},{x:tower.x+30,y:tower.y+30,width:20,height:20})){
            var money = Math.floor((tower.level * TowerType[tower.type]["level_1"].buyIt)/2);
            this.updateScore(money);
            delete this.installTower[Math.floor(tower.x/50)+"_"+Math.floor(tower.y/50)];
            Game.towerList.remove(tower);
            Canvas.clearRect(Game.canvasList.tower,tower.x,tower.y,tower.width,tower.height);
            Canvas.clear(Game.canvasList.select,500,500);
            tower = null;
            //sell
        }
    }

//初始化绑定塔的事件
    initBind : function(){
        var select = document.getElementById("select");
        select.onclick = function(e){
            var x = e.offsetX || e.layerX,
                y = e.offsetY || e.layerY;
            //遍历塔的列表
            for(var i=0,l=Game.towerList.length;i<l;i++){
                //判断是否选择到了塔
                if(T.pointInRect({x:x,y:y},Game.towerList[i])){
                    //画出范围
                    Info.drawScope(Game.towerList[i]);
                    if(Game.nowSelectTower){
                        //升级或卖掉
                        Info.upgradeOrSell(x,y);
                    }
                    Game.nowSelectTower = Game.towerList[i];
                    break;
                }
            }
            //没有选中,清除
            if(i == l){
                Canvas.clear(Game.canvasList.select,500,500);
                Game.nowSelectTower = null;
            }
        }
    }

//重新开始
    restart : function(){
        this.stop();
        this.towerList = [];
        this.enemyList = [];
        this.bulletList = [];
        this.mission = 0;
        this.missionEnemey = 0;
        this.missionLazy = 2000;
        this.enemyLazy = 0;
        this.nowSelectTower = null;
        Info.score = 100;
        Info.life = 10;
        Info.mission = 1;
        Info.installTower = {};
        Canvas.clear(this.canvasList.map,500,500);
        Canvas.clear(this.canvasList.main,500,500);
        Canvas.clear(this.canvasList.tower,500,500);
        Canvas.clear(this.canvasList.select,500,500);
        Info.redraw();
        this.start();
    },
    //停止
    stop : function(){
        clearInterval(this.timer);
    },
    //结束
    over : function(){
        this.stop();
        alert("你输了!");
    },
    //赢了
    win : function(){
        this.stop();
        alert("你赢了!");
    }