SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package dev.shadowtail.squirrelquarrel;

import java.io.IOException;
import java.io.InputStream;
import java.util.Random;
import javax.microedition.lcdui.Image;

/**
 * This manages the world map which consists of tiles.
 *
 * @since 2019/07/01
 */
public final class TileMap
{
    /** Each tile is 16x16 pixels. */
    public static final int TILE_PIXELS =
        16;
    
    /** Mask for pixels. */
    public static final int TILE_PIXELS_MASK =
        15;
    
    /** The tile background mask. */
    public static final int TILE_BACKGOUND_MASK =
        0b0000_0011;
    
    /** Background tile images. */
    private static final Image[] _CACHE_BACKGROUND =
        new Image[4];
    
    /** The size of the map. */
    public final MapSize size;
    
    /** The width of the map in tiles. */
    public final int tilewidth;
    
    /** The height of the map in tiles. */
    public final int tileheight;
    
    /** The internal tile data. */
    final byte[] _tiles;
    
    /**
     * Initializes the tile map.
     *
     * @param __rand The random level generator.
     * @param __size The map size to use.
     * @param __numpl The number of players to make room for.
     * @throws IllegalArgumentException If the player count is zero or
     * negative.
     * @throws NullPointerException On null arguments.
     * @since 2019/07/01
     */
    public TileMap(Random __rand, MapSize __size, int __numpl)
        throws IllegalArgumentException, NullPointerException
    {
        if (__rand == null || __size == null)
            throw new NullPointerException("NARG");
        
        /* {@squirreljme.error BE0r Negative or zero players, there must be
        at least one player. (The player count)} */
        if (__numpl < 1)
            throw new IllegalArgumentException("BE0r " + __numpl);
        
        // Get and store size of the level
        int tilewidth = __size.width,
            tileheight = __size.height,
            tiledens = tilewidth * tileheight;
        this.size = __size;
        this.tilewidth = tilewidth;
        this.tileheight = tileheight;
        
        // Initialize data areas
        byte[] tiles = new byte[tiledens];
        this._tiles = tiles;
        
        for (int i = 0; i < tiledens; i++)
            tiles[i] = (byte)__rand.nextInt();
    }
    
    /**
     * Looks into the cache and returns the specified image.
     *
     * @param __cache The cache to look in.
     * @param __dx The index to cache.
     * @param __prefix The resource prefix.
     * @return The resulting image.
     * @throws NullPointerException On null arguments.
     * @since 2019/07/02
     */
    public static Image cacheImage(Image[] __cache, int __dx, String __prefix)
        throws NullPointerException
    {
        if (__cache == null || __prefix == null)
            throw new NullPointerException("NARG");
        
        // If the cache has the image, use it
        Image rv = __cache[__dx];
        if (rv != null)
            return rv;
        
        // Otherwise load it!
        try (InputStream in = TileMap.class.getResourceAsStream(
            __prefix + __dx + ".xpm"))
        {
            rv = Image.createImage(in);
        }
        
        /* {@squirreljme.error BE0t Could not cache the image. (The index;
        The prefix)} */
        catch (IOException e)
        {
            throw new RuntimeException("BE0t " + __dx + " " + __prefix, e);
        }
        
        // Store into the cache then return
        __cache[__dx] = rv;
        return rv;
    }
    
    /**
     * Gets the image used for the background.
     *
     * @param __b The tile data.
     * @return The image to use.
     * @since 2019/07/02
     */
    public static Image imageBackground(byte __b)
    {
        // Read cached image
        return TileMap.cacheImage(
            TileMap._CACHE_BACKGROUND, __b & TileMap.TILE_BACKGOUND_MASK,
            "tile");
    }
}