Can I use one set of images to represent multiple sprites in Java?

Saturday, November 26, 2011 by Nate Bross

Someone asked on Game Development:

I’ve got a game that has 3 basic sprites, at the moment I’m loading 8 images into each sprite for animating. Each character class has a sprite object. if I’ve got 10 characters on screen at once then that’s 80 images loaded in to memory. Can I make a central sprite class that only holds 8 images for each of the 3 sprites, then get the character objects to request the relevant images from the central sprite class, thereby massively reducing the memory required for the images?

I posted the following answer, which was chosen as the accepted answer and received 2 upvotes:

You can and you probably should. I believe that in Java (as in C#) objects are going to be passed by reference, so you should get this behavior by default without doing any extra work.

Code like this:

Sprite spr = Sprite.LoadFromFile("c:\sprite.s");

Character c1 = new Character(spr, x1, y1);
Character c2 = new Character(spr, x2, y2);
Character c3 = new Character(spr, x3, y3);

Should give you three Character objects all referencing the same Sprite object.

A quick search shows that I stand corrected. Java is in fact pass-by-value; however, since java has “pointers” the result in the code above should remain the same. Java passes the pointer to the sprite by value; but they will all still “reference” the same sprite.

Originally posted on Game Development — 2 upvotes (accepted answer). Licensed under CC BY-SA.