Hop

A lightweight 2D game engine, in C++ with embedded Lua

Features

• Free, MIT open sourced..
• Use as a standalone engine or as a drop in component (e.g. with SFML)..
• Entity component system (ECS) based.
• Physics (Discrete element method):
  • [x] collision primitives (circles, rects).
  • [x] collision meshes built from primitives (rigid and soft).
  • [x] configurable friction, gravity, drag, and restitution.
  • [x] super-sampling.
  • [ ] (good) multithreading.
  • [x] Cell list collision detection.
  • [ ] Quad tree collision detection.
  • [x] Object-object and object-world collisions.
  • [ ] collision islands and other optimisations.
• Rendering (provided by jGL, Vulkan is a WIP):
  • [x] OpenGL.
  • [ ] Vulkan.
  • [x] sprites (atlasing, and animateable atlases).
  • [x] collision primitives (circles/rects).
  • [x] Freetype fonts.
  • [ ] shapes (it is in jGL).
  • [ ] lightmaps and shadows.
  • [x] msaa.
  • [ ] particle effects (it is in jGL).
  • [x] texture management.
  • [ ] (compressed) texture asset packs.
  • [ ] Engine UI (Dear ImGui).
• Window management:
  • [x] Single window creation.
  • [ ] Multi-window.
  • [x] Key and mouse events.
  • [x] Frame limiting.
  • [ ] Snapping and resizing.
  • [x] Screenspace bbs.
• Worlds:
  • [x] Perlin (marching squares).
  • [x] Tile maps.
  • [x] object-world collisions.
  • [ ] editable.
  • [x] saveable.
  • [ ] tile textures.
• Lua console
  • [x] ECS bindings (object management).
  • [x] Compressed script asset archive support.
  • [ ] Live in game console
• Cross platform:
  • [x] Linux.
  • [x] Windows.
  • [x] macOS.
  • [x] Android.
  • [ ] IOS (mostly held up by jGL rendering).
• Tooling
  • [x] mesh editor.
  • [x] Lua script packer.
  • [ ] World editor.
  • [ ] Texture packer.

Documentation

Checkout the docs here, and also the jGL docs here

Setup

• clone, and init the submodules (you can use submodules.sh)
• the build.sh can be used to build

OSS Dependencies and Licenses

• Freetype is licensed under the The FreeType Project LICENSE
• GLEW is licensed under aModified BSD License, the Mesa 3-D License (MIT) and the Khronos License (MIT).
• GLFW is licensed under the zlib/libpng
• GLM is licensed under the MIT License (but also, no bunnies have been made unhappy)
• Lua is licensed under the MIT license
• Miniaudio is licensed under the MIT-0 license
• stduuid is licensed under the MIT license
• vorbis and ogg is licensed under a BSD license
• zlib is licensed under the zlib license

Thanks to all the OSS developers: David Turner, Robert Wilhelm, and Werner Lemberg (Freetype), Milan Ikits <milan ikits[]ieee org>, Marcelo E. Magallon <mmagallo[]debian org>, and Lev Povalahev Brian Paul, The Khronos Group Inc (GLEW), Marcus Geelnard and Camilla Löwy (GLFW), G-Truc Creation (GLM), Lua.org, PUC-Rio (Lua), David Reid (Miniaudio), Marius Bancila https://github.com/mariusbancila/stduuid#MIT-1-ov-file (stduuid), Xiph.org Foundation (vorbis, ogg), and Jean-loup Gailly and Mark Adler (zlib).