Purpose: I'm disappointed in the direction that Unity (as a game engine, and as a company) has been going for a while. However, it's taught me so much about game development and API design, and inspired my interest in free, open source, stable, and extensible software with a focus on RPGs for PC and console gaming.
I'm deciding to learn an immense amount of C++, to give me much more freedom as a developer, and perhaps even potential to contribute someday to open source projects like the Godot engine, or learn Unreal engine.
I hope this project helps to provide a human-friendly, more understandable example of working with many C++ libraries to create a small, specialized game engine.
- ✅ Windows
- ✅ MacOS (Intel64 and Arm64 (M1/M2))
- ✅ Linux (tested on Zorin/Ubuntu)
- ✅ Raspberry Pi (tested on arm64 (Debian-based))
Note that I use the Git Bash with VS Code.
1: This repo uses Git submodules for my C++ CMake build scripts, some of the libraries, so you may need to run:
git submodule update --init --recursive2: You can make the build and run commands more easily available using the following command to set some shortcut ("alias") commands for your current terminal session:
source ./cmake-scripts/aliases.shIt will tell you the newly-available commands.
3: Then, you can simply just run the following to build and run the release mode of this project:
build && run-releaseℹ️ For more details on what those build and run scripts are doing, check out the cmake-scripts Git submodule under /cmake-scripts and read its README.md.
See this for descriptions of the libraries/dependencies I use.
- Small (C++ Program) Examples
- (See these for simpler, smaller examples of learning various topics)
- Includes examples for ECS, JSON, OpenGL, UTF-8 cross-platform, File I/O, and more!
This is a learning project, where I gather a lot of my C++/C#/game engine notes over time, and show off small examples for learning purposes.
My complete game engine is private, but this Git repo gives you a lot of the basics to start with, if you're curious about making your own game engine.
Here are some things I'd like to do next:
-
Features/Bugs:
- Upgrade the ServiceLocator implementation (in the main program under
/src) to use templates to let you define the base class that all your systems must inherit from, rather than hard-coding it to use IGameLoopSystems. - (A lot of work) Investigate into performance -- For some reason, the OpenGL draw calls I have with grass tiles are really heavy. I not only want to employ optimization techniques like frustum culling, draw call batching, and GPU instancing, but I also want to understand if there's any ways to optimize the code as-is if my game actually did need to keep 100s of draw calls per frame.
- 🐛 For some reason, I've noticed that changing the shader from our source code's "resources" folder updates the already-built builds upon next run. The C++ program should really be reading from the /out folder's resources folder instead.
- Dear ImGUI:
- 🐛 Dear ImGUI's
ImGui_ImplOpenGL3_RenderDrawData(...)function throws a 1280 (0x500) GL_INVALID_ENUM OpenGL error during drawing on 64bit Raspberry Pi (OpenGL ES 3.1). - 🐛 I need to somehow fix an issue with Dear IMGUI where Tab/Shift + Tab navigation on the keyboard is not working at all.
- I want to restrict all GUI to the GLFW window, so they can't get cut off-screen.
- I want to display float fields without forcing a specific number of decimal places.
- 🐛 Dear ImGUI's
- Upgrade the ServiceLocator implementation (in the main program under
-
Documentation:
- I need to document the setup better for .NET hosting.
- I want to better document how I switch between using OpenGL and OpenGL ES, and the pros/cons of the current approach's use of "pre-assumptions" about the current platform.
- I want to document and measure the most performant way(s) of calling out to C# code, especially during the game loop.
- I want to better document what the setup was for getting the small example UTF-8 program to work.
See my backlog for other, lower priority learning goals.