gistfile1.java

public class Blur {
    final static int RED   = 0;
    final static int GREEN = 1;
    final static int BLUE  = 2;

    final static int width  = 640;
    final static int height = 480;

    final static int frames = 1000;
    final static int N = 13;
    
    private static int index(int x, int y, int color) {
        return (y*width + x)*3 + color;
    }
    
    private static int unsigned(byte b) {
        return b & 0xFF;
    }

    private static void blur(byte in[], byte out[]) {
        for (int y=1; y<height-1; y++) {
            for (int x=1; x<width-1; x++) {
                for (int c = RED; c<=BLUE; c++)
                    out[index(x,y,c)] = (byte) ((unsigned(in[index(x,y-1,c)]) + 
                                                 unsigned(in[index(x,y+1,c)]) + 
                                                 unsigned(in[index(x-1,y,c)]) + 
                                                 unsigned(in[index(x+1,y,c)])) /4);
            }
        }
    }

    public static void main(String argv[]) {        
        final int len = width * height * (BLUE+1);
        byte a1[] = new byte[len];
        byte a2[] = new byte[len];
        System.out.println("start");
        long time = System.currentTimeMillis();
        
        for (int f = 0; f<frames; f++) {
            for (int n = 0; n<N; n++) {
                blur(a1,a2);
                blur(a2,a1);
            }
        }
        System.out.println(System.currentTimeMillis() - time);
    }
}