1

我正在尝试将敌舰绘制到画布上，该画布将从右侧随机出现 x 是画布的高度，随机 y 超过右侧 + 1000。

这工作正常但是我试图使其自动化并且代码运行运行它只是在屏幕上不起作用，只绘制了 1？您需要的任何更多信息都可以问，这真的让我的大脑很煎熬，我一行一行地走了大约 3 个小时，但看不到任何问题。

在我添加此代码并手动调用之前：http ://www.taffatech.com/DarkOrbit.html

在我为自动添加此代码后：（看起来有点重叠） http://www.taffatech.com/test.html

全局变量：

var spawnInterval;
var totalEnemies = 0; //leave as is
var enemies = [];  //array of enemy objects
var spawnRate = 2000; //every 2 seconds
var spawnAmount = 3; //amount of enemies spawned

然后我的 init() 调用一个 startLoop：

function startLoop()
{

isPlaying = true;
Loop();
startSpawningEnemies();

}

function stopLoop()
{
isPlaying = false;
stopSpawningEnemies();
}

function Loop()
{
if (isPlaying == true)
{
Player1.draw();
requestAnimFrame(Loop);
 drawAllEnemies();

}

然后他们使用这些功能：

function spawnEnemy(n) //total enemies starts at 0 and every-time you add to array
{
  for (var x = 0; x < n; x++)
   {

     enemies[totalEnemies] = new Enemy();
     totalEnemies++; 
   }

}

function drawAllEnemies()
{

  ClearEnemyCanvas();
  for(var i = 0; i < enemies.length; i++)
   {
      enemies[1].draw();

   }
}

function startSpawningEnemies()
{
  stopSpawningEnemies();

  spawnInterval = setInterval(function() {spawnEnemy(spawnAmount);}, spawnRate); //this calls spawnEnemy every spawnRate
  /////////spawn 'spawnAmount' enemies every 2 seconds




}


function stopSpawningEnemies()
{

clearInterval(

spawnInterval);
}

它又调用 Enemy 类：

function Enemy()  //Object
{

//////Your ships values
this.EnemyHullMax = 1000;
this.EnemyHull = 1000;
this.EnemyShieldMax = 1000;
this.EnemyShield = 347;
this.SpaceCrystalReward = 2684;
this.EnemySpeed = 2; //should be around 6 pixels every-time draw is called by interval, directly linked to the fps global variable
////////////



////Pick Ship
this.type = "Hover";
this.srcX = EnemySrcXPicker(this.type);
this.srcY = EnemySrcYPicker(this.type);

this.enemyWidth = EnemyWidthPicker(this.type);
this.enemyHeight = EnemyHeightPicker(this.type);

this.drawX = EnemydrawXPicker(this.type);
this.drawY = EnemydrawYPicker(this.type);
////


}

Enemy.prototype.draw = function()
{

this.drawX -= this.EnemySpeed;
ctxEnemy.globalAlpha=1;
ctxEnemy.drawImage(spriteImage,this.srcX,this.srcY,this.enemyWidth,this.enemyHeight,this.drawX,this.drawY,this.enemyWidth,this.enemyHeight);

}



function EnemySrcXPicker(type)
{
if (type == "Hover")

    {

        return 906;
      }
}

function EnemySrcYPicker(type)
{
if (type == "Hover")

   {
        return 616;
     }
}

function EnemydrawXPicker(type)
{
if (type == "Hover")

     {
        return Math.floor(Math.random() *  1000) + canvasWidthEnemy;
     }
}

function EnemydrawYPicker(type)
{
if (type== "Hover")

     {
        return Math.floor(Math.random() * (canvasHeightEnemy - 72));
     }
}


function EnemyWidthPicker(type)
{
if (type == "Hover")

     {
        return 90;
     }
}

function EnemyHeightPicker(type)
{
if (type == "Hover")

     {

        return 72;
     }
}
4

3 回答 3

2 
for(var i = 0; i < enemies.length; i++)
{
   enemies[1].draw();
}

应该是

for(var i = 0; i < enemies.length; i++)
{
   enemies[i].draw();
}

...or you'll draw the same enemy over and over.

于 2013-06-04T18:56:20.103 回答
0

In your drawAllEnemies function, shouldn't

enemies[1].draw();

be

enemies[i].draw();

?

于 2013-06-04T18:58:04.777 回答
0

When you loop the enemies array you should use the index i that you setup so that it doesn't continually draw the same element:

for(var i = 0; i < enemies.length; i++)
{
   enemies[i].draw();
}
于 2013-06-04T19:16:09.063 回答