如何使用Java在png图像上创建网格图？

Question

The thing is that i'm helping a friend with a java project for the universty, and we have to create a remake of MSX's Knightmare. The game is pretty developed already but we don't know how to create the collision with the scenary's stuff, like the columns and the bridge over the river. In order to do this i thought that we could just create a logical "grid-mapping" over the png (the whole level is this image, invoked on the game like a plain image) and do the logic on it, just a boolean logic.

So the basic way, that i suggest to do, is a 2D array with this grid calculated on our minds. Is there some tool that we could use in order to do this easier or automated somehow?

Knightmare original version video

And this is the image that we are using on the game

Answer 1

I am going to try answering the title question, which seemed like the important one.

I wrote a little platform game in Java some time ago, and there I wrote a method called comprobarColisiones() (check collisions) which I call everytime

// Check collisions
comprobarColisiones();

h.mover(pasadas); //Move hero

// Moving enemies
if (h.x > en.getX()){
    en.mover(h.getdx(), h.getIzq(),pasadas);
}
if (h.x> en2.getX()){
    en2.mover(h.getdx(), h.getIzq(),pasadas);
}

// Moving static objects (rocks)
roca1.mover(h.getdx(),h.getIzq());
roca2.mover(h.getdx(),h.getIzq());
roca3.mover(h.getdx(),h.getIzq());

// REPAINTING
repaint();

// A time calculation that I use to control the game speed somewhere
tiempoAnteriorTipito = System.currentTimeMillis();

When I mean "static objects" it's just to differentiate objects with self-movement with those that just scroll as long as the hero moves, in your game (as in mine's) there probably will not be any static object (well, probably the scores and stuff), even rocks will scroll.

public void comprobarColisiones(){

    // Getting bounds
    Rectangle r1 = en.getBounds();
    Rectangle r2 = en2.getBounds();
    Rectangle rec_roca1 = roca1.getBounds();
    Rectangle rec_roca2 = roca2.getBounds();
    Rectangle rec_roca3 = roca3.getBounds();

    // Getting bounds and resolving collisions with shooting objects
    ArrayList martillos = Heroe.getMartillos();
    for (int i = 0; i < martillos.size(); i++) {

            Martillo m = (Martillo) martillos.get(i);
            Rectangle m1 = m.getBounds();
            if (r1.intersects(m1) && en.vive())
            {
                    en.setVive(false);
                    m.visible = false;
            }
            else if (r2.intersects(m1)&& en2.vive())
            {
                    en2.setVive(false);
                    m.visible = false;                        
            }
    }

    // Checking if hero touches enemies

    Rectangle heroecuad = h.getBounds();
    if (heroecuad.intersects(r1)&&en.vive()){
        perdio = true;
        System.out.println("PERDIO CON EL ENEMIGO 1");
    }
    if (heroecuad.intersects(r2)&&en2.vive()){
        perdio = true;
        System.out.println("PERDIO CON EL ENEMIGO 2");
    }

    // Checking if hero touches static objects

    if(heroecuad.intersects(rec_roca1)){
        System.out.println("CHOCO ROCA 1");
    }

    if(heroecuad.intersects(rec_roca2)){
        System.out.println("CHOCO ROCA 2");
    }        

    if(heroecuad.intersects(rec_roca3)){
        System.out.println("CHOCO ROCA 3");
    }        
}

I created enemies and static stuff and placed them when I load the escenario, just like this:

en = new Enemigo(800, ALTURA_PISO+8);
en2 = new Enemigo(900, ALTURA_PISO+8);

roca1 = new Roca(1650, ALTURA_PISO+17);
roca2 = new Roca(2200, ALTURA_PISO+17);
roca3 = new Roca(3400, ALTURA_PISO+17);

// Being the first number the initial X-Pos and the second the initial Y-Pos, this will change everytime the hero moves, of course

Probably in your game, you'll define any area of the map as explorable, and add some ghost objects to check intersection with the hero and stop his movement. For what I could see, water and columns should NOT be explorable by your hero.

Hope this would give you some ideas.