thump 0.2.1

A simple axis-aligned bounding box collisions system.

Thump

Description

A simple 2D collision system for axis-aligned bounding boxes.

Features

• Tunneling - No matter the speed of an object it will hit anything it collides with, provided the dimensions of the objects is >= 1.
• Slide, Pass, Touch, Bounce behaviors when resolving collisions.

Example

import 'package:thump/thump.dart';

void main() {
  final Object block = Object();
  final Object man = Object();
  final World world = World(1024, 1024);
  world.add(block, AABB.xywh(x: 64, y: 16, width: 16, height: 16));
  world.add(man, AABB.xywh(x: 47, y: 16, width: 16, height: 16));
  MoveResult result = world.move(man, 2, 0);
  print(result.collisions.length);
}

Algorithm

1. Store objects in quadtree.
2. Create a union AABB around the starting point and ending point.
3. Query quadtree with the union to find potential collisions.
4. Move the object <= 1 units (Nyquist frequency) at a time checking against potential collisions and resolving behaviors.

To do

• Create infastructure to run all benchmarks.

Potential optimizations

1. Instead of using a union AABB to calculate potential collisions, use a convex hull around starting and ending AABB.
2. Sort potential collisions based on their distance to the starting point.
3. Have a private AABB that is mutable to avoid generating garbage.
4. Make potentials come back as a mini quadtree
5. Divide large Move()'s into smaller moves

Recognitions

The API was inspired by bump.lua. That is an excellent physics engine and much more impressive than this one. This is a simplified equivalent that I implemented when really wanted it for Dart.

License

MIT