Intro

I wrote this libGDX library because I needed to group a bunch of game objects together in chunks in a grid to cull them faster. If for whatever reason a quad tree datastructure doesn't suit your needs, feel free to check this library out.

Features

• Create a Grid of Chunks that hold whatever Object you want.
• Grid automatically resizes by creating new chunks to encompass any new Object you add to the Grid that is positioned outside of the Grid.
• Query the grid with a point or polygon to receive chunks in that region.
• Option to add overshoots to the chunks if you want them to overlap over each other.

Installation

Add this in your root build.gradle at the end of repositories:

allprojects { repositories { ... maven { url 'https://jitpack.io' } } }

Then add the dependency

dependencies { implementation 'com.github.BambooBandit:ChunkJunk:6fb5fe1d76' }

Now you should be good to go.

Usage

Make a Grid with initial column, row count (can both be 0 if you want to start with 0 chunks), chunk size, and optionally, overshoot (to allow chunks to overlap)

Grid grid = new Grid(columns, rows, chunkSize, chunkOvershoot);

Now you can add whatever objects you want to the grid by giving it either a point or a polygon, and the grid will add them to the appropriate chunks, or create new chunks if necessary.

grid.add(x, y, object);

grid.add(new float[]{0, 0, 1, 1, 1, 0}, object);

And query the grid for the chunks by giving it either a point or polygon. Keep in mind that grid.getChunks returns a reusable array to prevent garbage creation, so work with it as soon as you call it and don't hold on to it.

Array<Chunk> chunks = grid.getChunks(x, y);

Array<Chunk> chunks = grid.getChunks(new float[]{0, 0, 1, 1, 1, 0});

And that's pretty much it!

Performance

Since the chunks are indexed, you can quickly access a chunk with a point in O(1) time complexity. Querying with a polygon or with overshoots (overlapping chunks) aren't as fast because once necessary chunks are accessed, neighboring chunks have their bounds checked.

Demo

Included in this repo is a libGDX graphical demo of this library. Controls:

• Left mouse click to add new point to grid
• Right mouse click to plot polygon points. Enter to finish polygon and add it to grid.
• Arrow keys to move camera.
• Comma and Period to zoom in and out.
• R to reset the grid.