gamecore/src/mightypork/gamecore/graphics/textures/TxSheet.java

package mightypork.gamecore.graphics.textures;


import java.util.Random;

import mightypork.utils.logging.Log;


/**
 * Basic sprite sheet (cuts a {@link TxQuad} to a number of same-sized
 * sub-quads)
 *
 * @author Ondřej Hruška (MightyPork)
 */
public class TxSheet {
	
	private final TxQuad original;
	private final TxQuad[] sprites;
	private final int width;
	
	private final Random rand = new Random();
	private final Random randForSeed = new Random();
	private final int count;
	
	
	/**
	 * Make a sprite sheet
	 *
	 * @param tx backing texture quad
	 * @param width number of tiles horizontally
	 * @param height number of tiles vertically
	 */
	public TxSheet(TxQuad tx, int width, int height)
	{
		this.original = tx;
		this.width = width;
		this.count = width * height;
		
		this.sprites = new TxQuad[count];
	}
	
	
	/**
	 * @return number of quads
	 */
	public int getQuadCount()
	{
		return count;
	}
	
	
	/**
	 * Get a quad based on ratio 0-1 (0: first, 1: last)
	 *
	 * @param ratio ratio
	 * @return quad
	 */
	public TxQuad getQuad(double ratio)
	{
		return getQuad((int) Math.round((count - 1) * ratio));
	}
	
	
	/**
	 * Get quad of index
	 *
	 * @param index index
	 * @return the quad
	 */
	public TxQuad getQuad(int index)
	{
		if (index < 0 || index >= count) {
			Log.w("Index out of bounds: " + index + ", allowed: 0.." + count);
			index = index % count;
		}
		
		// lazy - init only when needed
		if (sprites[index] == null) {
			final int x = index % width;
			final int y = index / width;
			
			final double origW = original.uvs.width().value();
			final double origH = original.uvs.height().value();
			
			final TxQuad txq = new TxQuad(original.tx, original.uvs.move(x * origW, y * origH));
			txq.dupeAttrs(original);
			
			sprites[index] = txq;
		}
		
		return sprites[index];
	}
	
	
	/**
	 * Get entirely random TxQuad from this sheet
	 *
	 * @return the picked quad
	 */
	public TxQuad getRandomQuad()
	{
		return getQuad(rand.nextInt(count));
	}
	
	
	/**
	 * Get random TxQuad from this sheet
	 *
	 * @param seed random number generator seed
	 * @return the picked quad
	 */
	public TxQuad getRandomQuad(long seed)
	{
		randForSeed.setSeed(seed);
		return getQuad(randForSeed.nextInt(count));
	}
	
	
	/**
	 * Get random TxQuad from this sheet
	 *
	 * @param seed random number generator seed (double will be converted to
	 *            long)
	 * @return the picked quad
	 */
	public TxQuad getRandomQuad(double seed)
	{
		return getRandomQuad(Double.doubleToLongBits(seed));
	}
}