如何从andEngine GLES2中的精灵表中获取特定的精灵？

Question

I have sprite sheet which is not managed row and column wise. But i have the pixel cordinates,height and width of the each sprite in the sprite sheet. I far i as know i should be able to get one particular image by

    spaceshipTexture = new BitmapTextureAtlas(getTextureManager(),1024,512,TextureOptions.BILINEAR_PREMULTIPLYALPHA);
    playerTextureRegion= BitmapTextureAtlasTextureRegionFactory.createFromAsset(spaceshipTexture, 
            this, "spaceshipsheet.png",0,119);

Here i have supplied the x-cordinate and y-cordinate of sprite as last two parameter in createFromAsset function. Shouldn't it return me that particular image located in that coordinate in sprite sheet? Instead it is return me the whole sprite. If i am not getting the function properly then please explain me what does those last two parameters means? How can i get a particular sprite?? Help me i am just new to andEngine.

Answer 1

Because your spritesheet is not managed row or column wise you wont benefit from BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset which allows you to set your row and column numbers.

However, I am in the same position as you so here is what I done (using your code).

spaceshipTexture = new BitmapTextureAtlas(getTextureManager(), 1024, 512, TextureOptions.BILINEAR_PREMULTIPLYALPHA);

playerTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(spaceshipTexture, 
        this, "spaceshipsheet.png", 0, 0); // start reading from the start of your spritesheet, so you can set multiple sprites

playerTextureRegion.set(0, 109, 20, 20); // pTextureX, pTextureY, pTextureWidth, pTextureHeight -- here you grab the sprite from the spritesheet

The last two parameters (from your initial question) are pTextureX and pTextureY which set the location to start reading from your spritesheet. Which is why you were still getting everything returned to you.

Hope this helps.

Answer 2

the procedure is: Set the texture atlas - done; Set the texture region - done // imagine them as a stickers on the sheet of paper, you can have a lot of them, just keep in mind that they cannot overlap, or go over the atlas

and now its easy: you set your sprite like this:

 Sprite yourSprite = new Sprite(x, y, playerTextureRegion, vertexBufferObjectManager);

As you can see you put your textureregion as the parametr in the construcotr. This way you do not have to put any coordinates for the texture region here.

Also remember to attach your sprite to the scene:

mScene.attachChild(yourSprite);