GalaxyInPixels/src/com/annimon/gipgame/BackgroundCreator.java

package com.annimon.gipgame;

import java.util.ArrayList;


public class BackgroundCreator {
    
    private static final boolean ANTI_ALIAS = true;
    
    private static final int WIDTH = 5;
    private int height = 12;

    private ArrayList<int[]> background;
    
    public BackgroundCreator() {
        background = new ArrayList<int[]>();
        
        createBackground();
    }
    
    public void setHeight(int height) {
        this.height = height; 
    }
    
    public int[][] getBackground() {
        int[][] array =  background.toArray(new int[0][]);
        if (!ANTI_ALIAS) return array;
        
        // Smooth background colors.
        int[][] antialias = new int[height][WIDTH];
        for(int y = 0; y < height; y++) {
            for (int x = 0; x < WIDTH; x++) {
                int top =     (y > 0)            ? array[y - 1][x] : 0;
                int bottom =  (y < (height - 1)) ? array[y + 1][x] : 0;
                int left =    (x > 0)            ? array[y][x - 1] : 0;
                int right =   (x < (WIDTH - 1))  ? array[y][x + 1] : 0;
                int center = array[y][x];
                
                antialias[y][x] = getAntiAliasColor(new int[] {top, bottom, left, right, center});
            }
        }
        return antialias;
    }
    
    private int getAntiAliasColor(int[] colors) {
        int red = 0;
        int green = 0;
        int blue = 0;
        
        for (int i = 0; i < 4; i++) {
            int color = colors[i];
            red += (color >> 16) & 0xFF;
            green += (color >> 8) & 0xFF;
            blue += color & 0xFF;
        }
        
        red /= 4;
        green /= 4;
        blue /= 4;
        
        red += (colors[4] >> 16) & 0xFF;
        green += (colors[4] >> 8) & 0xFF;
        blue += colors[4] & 0xFF;
        
        return 0xFF000000 | (red << 16) | (green << 8) | blue;
    }

    public void updateBackground(int addValue) {
        background.remove(height - 1);
        background.add(0, createRow(addValue));
    }
    

    private void createBackground() {
        for (int i = 0; i < height; i++) {
            background.add(createRow(0));
        }
    }
    
    private int[] createRow(int addValue) {
        int[] row = new int[WIDTH];
        for (int i = 0; i < WIDTH; i++) {
            row[i] = Util.randomSpaceColor(15 + (addValue / 2));
        }
        if (Util.rand(8) == 5) {
            // Create star.
            int x = Util.rand(WIDTH);
            int add = (addValue / 2);
            row[x] = Util.randomColor(10 + add, 60 + add);
        }
        return row;
    }
}