在游戏中绘制收藏品的最佳方法？

Question

I want my game to draw coins from a sprite and then my main character would be able to pick them up. I'm trying to use array list for this but i have no idea how to implement this feature. Do I make an array list of Sprites I need to draw and then reuse it ? If so , how ? Or do I use some other function ? I'm a begginer , so sorry if this question seems odd .

Answer 1

I recommend using Libgdx's Array class instead of a Java ArrayList, as it is optimized for game performance.

Create an Array to hold all the active coins.

Array<Sprite> activeCoins = new Array<Sprite>();

Then create a coin pool. A pool is a helper for creating copies of something without causing garbage collection hiccups. You need to make a subclass of Pool to use. It describes how to create a new coin when one is needed.

public class CoinPool extends Pool<Sprite> {
    TextureRegion coinTextureRegion;

    public CoinPool(TextureRegion coinTextureRegion){
        this.coinTextureRegion = coinTextureRegion;
    }

    protected Sprite newObject(){
        return new Sprite(coinTextureRegion);
    }
}

Then create an instance of CoinPool to use in your game.

Now whenever you want a new coin, pull one from the pool. It will only instantiate a new one if necessary. Otherwise, it will hand you a recycled one from earlier. And once you get it, set it's position and other parameters wherever you want it. Keep in mind it might still have old values attached to it, so if you are rotating your coins and moving them around or changing color, you'll want to be sure you reset position and rotation, and color.

Sprite newCoin = coinPool.obtain();
newCoin.setPosition(x,y,z); //as desired 
newCoin.setRotation(0); //if you are rotating them
newCoin.setColor(Color.WHITE); //if you have been changing their color

activeCoins.add(newCoin); //Add your new coin to the list of active coins

And whenever you are done with a coin (when it has been collected), you need to remove it from the active coins list and return it to the pool:

for (Sprite coin : activeCoins){
    boolean grabbed = isCoinGrabbed(coin); //however you want to do this
    if (grabbed){
        coinGrabbed(); //whatever you want to happen when a coin is grabbed

        activeCoins.remove(coin);
        coinPool.free(coin); //return it to the pool
    }
}

And to draw them, you can just submit all the sprites currently in the activeCoins list to the sprite batch.

Answer 2

I recently designed a game in Java that was a 2D side scrolling role playing game. Part of the game was to walk around and pick up items like swords and armor.

The way that I accomplished loading the sprites to my game was to give a JLabel my image (which was retrieved locally on start of the game) by setting it's icon to the image.

Next I would randomly place my JLabel on the game map. I didn't use an array list, although you could if you had multiple types of swords, or coins, etc.

The array list could contain types of swords (JLabel's with their icon set to a sprite) such as a bronze, silver, and a gold sword.

Once your JLabel('s) is loading to your map you can give them a hit box and if your character moves inside the hit box then remove the JLabel from the map and into the players backpack (or whatever it is, maybe append a coin amount?).