AS3 Embed images class and then get these images i

问题:

For example, right now I have a class called "Balls.as". Here I load 10 different balls-images. You know, like this:

[Embed(source = "/ball1.png")]
[Embed(source = "/ball2.png")]

The problem is that if I spawn 5 balls, these balls images gonna get embeded 5 * 5 times right? Correct me if I'm wrong! So I though, can't I have a ballimageloading class? That loads these images once, and then in Balls.as I can load whatever ball i want for the moment?

回答1:

The best practice is to have an Assets class which will contain static embeded images, like this:

[Embed(source="ball1.png")]
public static var BallImage1:Class;

Then all you'll have to do is declare a variable for your loaded Bitmap and use it, like so:

protected var mBall1:Bitmap = new Assets.BallImage1() as Bitmap;

This will create a Bitmap instance of your loaded image and you can then add it to the display list. Loading will happen only once per image and you'll have all your images at your fingertips, accessible from every class you have.

回答2:

You won't need to "load" them, they are embedded. You just have to instantiate the images. It's a good idea to have one class that manage shared ressources, as such:

public class TextureAssets 
{
    [Embed(source = "../lib/ball1.png")]
    private static var Ball1:Class;

    [Embed(source = "../lib/ball2.png")]
    private static var Ball2:Class;

    public static var ball1Texture:BitmapData;
    public static var ball2Texture:BitmapData;

    public static function init():void
    {
        ball1Texture = (new Ball1() as Bitmap).bitmapData;
        ball2Texture = (new Ball2() as Bitmap).bitmapData;
    }

Then you would call TextureAssets.init() once (in the Main.as for example) and when you need the bitmapData: use new Bitmap(TextureAssets.ball1Texture)
This way your program needs uses only memory required for one bitmapData instead of having many which ends up being the same.
If you need to perform operations on a bitmapData while keeping the original you can use:

var modified:bitmapData = TextureAssets.ballTexture.clone();

Also, if you are instantiating all balls images from within one class it's a good idea to drop static access and instead initialise the bitmapDatas in the constructor, create a new TextureAssets() and call the textures through the variable
(Static field access is slower than direct (.) access : http://jacksondunstan.com/articles/1690)