https://github.com/albin-johansson/abby

A header-only implementation of an AABB tree, written in C++17.
https://github.com/albin-johansson/abby

aabb aabb-trees axis-aligned-bounding-box collision-detection cpp17 cpp17-library game-development header-only hitbox mit-license

Last synced: 2 months ago
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A header-only implementation of an AABB tree, written in C++17.

• Host: GitHub
• URL: https://github.com/albin-johansson/abby
• Owner: albin-johansson
• License: other
• Created: 2020-07-04T16:12:38.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2021-01-09T19:01:33.000Z (almost 4 years ago)
• Last Synced: 2023-03-09T16:32:33.213Z (almost 2 years ago)
• Topics: aabb, aabb-trees, axis-aligned-bounding-box, collision-detection, cpp17, cpp17-library, game-development, header-only, hitbox, mit-license
• Language: C++
• Homepage:
• Size: 363 KB
• Stars: 7
• Watchers: 2
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# abby [![Build status](https://ci.appveyor.com/api/projects/status/p0ej0hg4cmemaeau?svg=true)](https://ci.appveyor.com/project/AlbinJohansson/abby) [![Build Status](https://travis-ci.org/albin-johansson/abby.svg?branch=dev)](https://travis-ci.org/albin-johansson/abby) ![version](https://img.shields.io/badge/version-0.2.0-blue.svg) [![Language](https://img.shields.io/badge/C%2B%2B-17-blue.svg)](https://en.wikipedia.org/wiki/C%2B%2B#Standardization) [![License](https://img.shields.io/badge/license-MIT-blue.svg)](https://opensource.org/licenses/MIT)

A header-only implementation of an AABB tree.

## Purpose

Collision detection is common in many applications, especially games. Subsequently, collision

detection often require checking for potential collision between many different game objects, and

as such it is important that the collision detection is efficient. A naive implementation will end

up with quadratic complexity, which isn't very scalable. By using an AABB tree, bounding hitboxes

are stored in a tree according to their position and size, which in turn enables logarithmic

complexity for collision detection.

## Example

```C++

  #include 

  #include  // back_inserter

  #include    // vector

  #include  // clog

  void foo()

  {

    // Constructs an AABB tree that uses integers as identifiers and AABBs with double precision

    abby::tree tree;

    // Inserts a few AABBs, takes a lower and upper bound

    tree.insert(1, {150.0, 165.0}, {50.0, 50.0});

    tree.insert(2, {88.0, 63.0}, {150.0, 343.0});

    tree.insert(3, {412.0, 132.0}, {566.0, 291.0});

    // Could also use a stack buffer

    std::vector candidates;  

    // Find collision candidates

    tree.query(1, std::back_inserter(candidates));  

    for (const auto candidate : candidates) {

      // Obtains an AABB

      const auto& aabb = tree.get_aabb(candidate);

    }

  

    // Prints the tree using a stream

    tree.print(std::clog);

    // Updates an existing AABB

    tree.update(2, {33.0, 76.0}, {123.0, 155.0});

    // Sets the position of an AABB

    tree.relocate(2, {12.0, 34.0});

    // Removes an AABB from the tree

    tree.erase(2);

    // Rebuild as optimal tree

    tree.rebuild();

    // Clear the tree of all entries

    tree.clear();

  }

```

## Acknowledgements

This library is an adapted and improved version of the [AABBCC](https://github.com/lohedges/aabbcc)

library. Furthermore, the AABB tree in the [Simple Voxel Engine](https://github.com/JamesRandall/SimpleVoxelEngine)

project also influenced the design of this library.