Problem with splitting BufferedImage

Newbie & Debugging Questions
#1

so here is where the problem is

	public void init(int worldSize, BufferedImage map){
		this.worldSize = worldSize;
		this.map = map;
		

		//createChunks
		int chunkW = map.getWidth() / worldSize;
		int chunkH = map.getHeight() / worldSize;
		
     	int count = 0;
		
		BufferedImage imgs[] = new BufferedImage[chunkW*chunkH];
		
		for (int x = 0; x < worldSize; x++) {  
            for (int y = 0; y < worldSize; y++) { 
				imgs[count] = new BufferedImage(chunkW, chunkH, map.getType());

        		Chunk chunke = new Chunk(x*8*32, y*8*32,imgs[count++]);	
            	chunkList.add(chunke);
				
				System.out.println(count+" IMG: "+map.getData()+" RGB: "+map.getRGB(x, y));
            }	
        }

		for(Chunk chunks : chunkList){
			chunks.initChunk();
		}
		
	}

what i’am trying to do is get 8 pixels out off the BF and create a chunk out off it then jump another 8 pixels and make a new chunk but they are all black when they go into the array why?

tell me if you need more info this is the chunk init

	public void initChunk(){
		
		
		if(currChunkImg != null){
			for(int w = 0; w < chunkSize; w++){
				for(int h = 0; h < chunkSize; h++){
					 int rgb = currChunkImg.getRGB(w, h);
					 
					 switch(rgb & 0x000000){
					 	case 0x000000:
					 		blocks.add(new Block(pos.xpos + w*32,pos.ypos + h*32));
						break;
//					 	case 0xFFFFFF:
//					 		blocks.add(new Block(pos.xpos + w*32,pos.ypos + h*32));
//						break;
					 }
					 
					 
				}
		        	 
			}
		}
		
	}

and when i render with

g.drawImage(currChunkImg,(int)pos.xpos, (int)pos.ypos,64,64,null);

in the chunk class
it shows a black image

#2

I don’t see where you are drawing to the BufferedImage. Of course the internal array is going to be all 0’s when you first create it, so all black.

#3

Depending on whether they actually need to be separate instances, you may get utility out of getSubImage().

E.g:


/** Split parent into numX by numY spritesheet */
public static BufferedImage[][] split(BufferedImage parent, int numX, int numY) {
    BufferedImage[][] tiles = new BufferedImage[numX][numY];
    int tileW = parent.getWidth() / numX;
    int tileH = parent.getHeight() / numY;

    for (int x = 0; x < numX; x++)
        for (int y = 0; y < numY; y++)
            tiles[x][y] = parent.getSubImage(x * tileW, y * tileH, tileW, tileH);

    return tiles;
}
#4

i want to get the data out off the map image and split in to smaller temp images

#5

Then do what BurntPizza suggests. I used a similar method for a thing I scribbled some two years ago (also implemented it in NodeJS since I was getting into that at the time) which cuts a sprite sheet into smaller icon-sized images - which then serves a random of these icons on each request through http.

http://d.heartpirates.com:40000/

http://twimg.jin.fi/

source for the nodejs implementation