Question

我试图将敌人的船只画在右边的画布上，随机的x是画布的高度，随机的y经过右边+ 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？你需要的任何更多信息，它真的在煎我的大脑我一行一行地走了大约3个小时，看不出问题。

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之后:(它看起来有点重叠） http://www.taffatech.com/test.html

全局：

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);
}

反过来调用敌人类：

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;
     }
}

Answer 1

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();
}

......或者你会一遍又一遍地吸引同一个敌人。

Answer 2

在你的drawAllEnemies函数中，不应该

enemies[1].draw();

是

enemies[i].draw();

Answer 3

当你循环enemies数组时，你应该使用你设置的索引i，这样它就不会连续绘制相同的元素：

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

画布超过1到画布不会工作？

3 个答案: