OpenMV

An open source Metroidvania.

Created from the ground up in C99.

Features

• Basic Rendering.
• Resource management.
• Code hot-reloading for game logic.
• Windows support.
• Physics.
• Audio.
• In-game GUI.
• Debug IMGUI.
• Save-game system.
• Room system.
• Resource Packing.
• Tilemap system.
• Dialogue system for NPCs.
• Scripting language.
• Command system to allow for easy configuration.
• Post processing.
• Actually make a damn game.

Building

Generate a Makefile using Premake and use that to compile everything.

Before you can run the game in release mode, build the packer project and run it from the project root to create a file named res.pck which contains all of the game's resources. The game reads from this file in release mode so that shipping the entire resource folder isn't required. The packer packs all of the files listed in packed.include; This file is sometimes out of date, so if the game struggles to load in release mode, try debug mode instead.

Dependencies on Linux:

• libdl
• libGL
• libm
• libX11
• libpthread

Dependencies on Windows:

• opengl32
• gdi32
• user32
• kernel32
• winmm

I develop everything under 64-bit GNU/Linux, with Clang and glibc. There's no reason why it wouldn't work under a 32-bit system with GCC, though (The Premake scripts will need to be modified to build under 32-bit). Windows should work, but I rarely test it, so some minor modifications might be needed here and there.

Note for MSVC users

OpenMV builds and runs under MSVC, as of recent. It relies on the __LINE__ preprocessor directive that is a part of ANSI C. However, Microsoft's edit and continue debugging feature does something stupid that causes this directive to be variable, which breaks the build. To "fix" this, you must disable the edit and continue feature in the project settings, by selecting "Program Database" under "Debug info" instead of "Program Database for Edit and Continue".

Using the Engine

You may use this project as a fairly solid foundation for other game projects. The renderer, entity component system, map loader, resource manager and audio systems are all fairly stable and bug-free to my knowledge. The scripting language and the IMGUI probably have bugs.

Using mksdk

Use mksdk if you want to use the bootstrapper with code hot reloading. This offers less control, but allows rapid prototyping.

A utility in util/mksdk exists so that manually copying files isn't required in order to create a new project. Simply build this project and run it from the project root to create a file named sdk.tar. Extract this file and start creating.

The default project creates a blank window and spams the console every frame. Edit the code in logic/src/main.c to create your game logic. All the code compiled in this project is hot-reloadable, meaning you can re-compile it and have the code update in real time without needing to restart the program. The default project also creates a loading screen while the on_init function in the logic project is running. Comment out lines 32-65 in bootstrapper/src/main.c to remove this if you don't want it.

Using the Core Library

Alternatively, you can simply use the core project by itself to manage things for a game. Doing this, you have manual control over things like the game loop.

By default, the core is built as a dynamic library. It can also be built as a static library, by editing the premake script. Note that this has some technical implications.

Levels

Levels are created using the Tiled level editor and exported using a custom binary format. An extension for Tiled to add this format can be found in tiledext/mapformat.js.

Vim

c.vim contains a Vim syntax file to highlight common types used in OpenMV's code, such as entity, null and v2f. It should be placed in your after/syntax folder, as c.vim.

Stuff by Other People

Below is a list of pieces of code that I didn't write:

• glad.
• microtar.
• miniaudio.
• stb_rect_pack.
• stb_truetype.

Everything else was written by me, from scratch.

Contributing

If you have plans to contribute code to this repository: First of all, thank-you for your time! Second, please follow the general style of the existing code as much as possible. This includes: Using tabs for indentation (not spaces), using double instead of float for timing and not typedef'ing structures or enumerations. Everything should adhere to standard C99 where possible or at the very least compile with Clang (minimise the use of GNU extensions). External libraries should also be avoided, though single-header utilities are fine.