CODEWITHSUNDEEP
javaarrays
Stas Jaro
Stas Jaro

Reputation: 4885

how to get coordinates of a linear array

i am making a game in which i have a 3d map stored int an array int integers:

int width = 256;
int height = 256;
int depth = 64;
int[] map = new int[width * height * depth];

i need to be able to get get the x, y, z of an index. the current method i came up with is:

private int getX(int blockID) {
    return blockID % width;
}

private int getY(int blockID) {
    return (blockID % depth) / height;
}

private int getDepth(int blockID) {
    return blockID / (width * height);
}

the methods for getting the x and the depth seem to work but i cannot get the getY() to work correctly and i keep getting and ArrayIndexOutOfBoundsException like the one below:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1
at game.Level.updateLighting(Level.java:98)
at game.Level.generateMap(Level.java:58)
at game.Level.<init>(Level.java:21)
at game.mainClass.main(Minecraft.java:6)

please help if you know how to do this.

Upvotes: 0

Views: 444

Answers (2)

NPE
NPE

Reputation: 500903

Try

private int getY(int blockID) {
    return (blockID / width) % height
}

Upvotes: 1

Matt Ball
Matt Ball

Reputation: 360026

Dude. Just use a 3D array.

int[][][] map = new int[width][height][depth];

Then you don't have to worry about demuxing x, y, and z indices from the blockID. They are lineary independent, so keep them that way.

Upvotes: 3

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