CodeChickenCore/src/codechicken/lib/render/SpriteSheetManager.java

package codechicken.lib.render;

import codechicken.lib.render.TextureUtils.IIconSelfRegister;
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;
import net.minecraft.client.renderer.texture.IIconRegister;
import net.minecraft.client.renderer.texture.TextureMap;
import net.minecraft.util.IIcon;
import net.minecraft.util.ResourceLocation;

import java.util.ArrayList;
import java.util.HashMap;

public class SpriteSheetManager
{
    @SideOnly(Side.CLIENT)
    public static class SpriteSheet implements IIconSelfRegister
    {
        private int tilesX;
        private int tilesY;
        private ArrayList<Integer> newSprites = new ArrayList<Integer>();
        private TextureSpecial[] sprites;
        private ResourceLocation resource;
        private TextureDataHolder texture;
        private int spriteWidth;
        private int spriteHeight;
        
        public int atlasIndex;
        
        private SpriteSheet(int tilesX, int tilesY, ResourceLocation textureFile)
        {
            this.tilesX = tilesX;
            this.tilesY = tilesY;
            this.resource = textureFile;
            sprites = new TextureSpecial[tilesX*tilesY];
        }
        
        public void requestIndicies(int... indicies)
        {
            for(int i : indicies)
                setupSprite(i);
        }
        
        public void registerIcons(IIconRegister register)
        {
            TextureMap textureMap = (TextureMap)register;
            
            if(TextureUtils.refreshTexture(textureMap, resource.getResourcePath()))
            {
                reloadTexture();
                for (TextureSpecial sprite : sprites)
                    if (sprite != null)
                        textureMap.setTextureEntry(sprite.getIconName(), sprite);
            }
            else
            {
                for(int i : newSprites)
                    textureMap.setTextureEntry(sprites[i].getIconName(), sprites[i]);
            }
            newSprites.clear();
        }
        
        public TextureSpecial setupSprite(int i)
        {
            if(sprites[i] == null)
            {
                String name = resource+"_"+i;
                sprites[i] = new TextureSpecial(name).baseFromSheet(this, i);
                newSprites.add(i);
            }
            return sprites[i];
        }

        private void reloadTexture()
        {
            texture = TextureUtils.loadTexture(resource);
            spriteWidth = texture.width/tilesX;
            spriteHeight = texture.height/tilesY;
        }

        public IIcon getSprite(int index)
        {
            IIcon i = sprites[index];
            if(i == null)
                throw new IllegalArgumentException("Sprite at index: "+index+" from texture file "+resource+" was not preloaded.");
            return i;
        }

        public TextureDataHolder createSprite(int spriteIndex)
        {
            int sx = spriteIndex%tilesX;
            int sy = spriteIndex/tilesX;
            TextureDataHolder sprite = new TextureDataHolder(spriteWidth, spriteHeight);
            TextureUtils.copySubImg(texture.data, texture.width, sx*spriteWidth, sy*spriteHeight, 
                    spriteWidth, spriteHeight, 
                    sprite.data, spriteWidth, 0, 0);
            return sprite;
        }

        public int spriteWidth()
        {
            return spriteWidth;
        }
        
        public int spriteHeight()
        {
            return spriteHeight;
        }

        public TextureSpecial bindTextureFX(int i, TextureFX textureFX)
        {
            return setupSprite(i).addTextureFX(textureFX);
        }

        public SpriteSheet selfRegister(int atlas)
        {
            TextureUtils.addIconRegistrar(this);
            return this;
        }
        
        @Override
        public int atlasIndex()
        {
            return atlasIndex;
        }
    }
    
    private static HashMap<String, SpriteSheet> spriteSheets = new HashMap<String, SpriteSheet>();
    
    public static SpriteSheet getSheet(ResourceLocation resource)
    {
        return getSheet(16, 16, resource);
    }

    public static SpriteSheet getSheet(int tilesX, int tilesY, ResourceLocation resource)
    {
        SpriteSheet sheet = spriteSheets.get(resource.toString());
        if(sheet == null)
            spriteSheets.put(resource.toString(), sheet = new SpriteSheet(tilesX, tilesY, resource));
        return sheet;
    }    
}