Loading from a sprite sheet

Game Mechanics
#1

Im currently using a very crappy method to load sprites and was wondering if anyone can point me to some documentation on how to create a nice class to load some tiles from.

  • john
#2

First, some basics: What framework are you even using?

#3

I have been building my own from scratch

#4

Stuff a SpriteSheet class needs:


// constructor
(Image, Dimension tileSize) -> SpriteSheet

// indexing function to get the subimages
(Int index) -> Image
   
    // the subimages are defined via rectangles, so we need a index-to-rectangle mapping:
    private (Int index) -> Rectangle
        // this will involve linear interpolation over both dimensions and the size of each subimage as defined in the constructor
   
    // your library of choice should provide a rectangle-to-subimage mapping, so plug it in

Try to break down your problems into functions and dependencies, your life will be easier.

#5

What I’m saying is, “is it based on Java2d or Opengl?”

#6

Java2d

#7

You could load the Spritesheet as a buffered image, determine all your rectangles as @BurntPizza said, and then use:

BufferedImage sprite = image.getSubimage(rectangle.x, rectangle.y, rectangle.width, rectangle.height); 
// rectangle is a given Rectangle object, image is the loaded image

Edit: If you just want a simple code snippet to look at, here’s a simple spritesheet class: http://pastebin.java-gaming.org/5c42f80441819
Note: it only works with the image being evenly divided into sections of Dimension spriteSize

CopyableCougar4

#8

Ive written some code for this , it returns a vertex2d object which is simply a container object with x , y ,u , v;
spritesheet:




package com.lcass.graphics.texture;

import org.lwjgl.opengl.GL11;

public class spritesheet {
	private Texture tex;
	private float x,y,ex,ey,width,height;
	public spritesheet(String location){
		tex = Texture.loadTexture(location);
		this.width = tex.width;
		this.height = tex.height;
	}
	public spritecomponent getcoords(int x, int y, int ex,int ey){
		spritecomponent temp= new spritecomponent();
		this.x = x/width;
		this.y = y/height;
		this.ex = ex/width;
		this.ey = ey/height;
		temp.set(this.x, this.y, this.ex, this.ey, tex);
		return temp;
	}
	public Texture gettexture(){
		return tex;
	}
}

then spritecomponent



package com.lcass.graphics.texture;

public class spritecomponent {
	public void set(float x, float y, float ex, float ey,Texture t){
		this.x = x;
		this.y = y;
		this.ex = ex;
		this.ey = ey;
		this.t = t;
		
	}
	public float x,y,ex,ey;
	public Texture t;
}

Simple and easy to use.
You just need to know how to load in textures , the rest is quite simple where ex ey are the end values x y are the beggining values and T is a texture object containing the width height and id of the texture object.

#9

OP said that he is working with Java2d, which means no GL commands or texture objects.

CopyableCougar4