Harpia Game Engine

28/05/2022

Game Engine made with learning purposes. My idea is to train my knowledge with C++ language and different aspects of engine/ development.

The original engine was started around 2008, with the name of RGine, being uploaded to Google Code in 2011 and migrated to Github in 2015. In 2022 I decided to give it another try and see how far I can get.

-- Ricardo Bustamante (aka Busta)

22/02/2026

I'm back and I have resurrected my game engine. Now it's improved and have support for other build platforms (Web/ItchIo)

-- Busta

Building

Requirements

All platforms: CMake 3.22+, Git, a C++17 compiler.

macOS: Xcode Command Line Tools (xcode-select --install).

Windows: MinGW-w64 (GCC) or Visual Studio 2022 (MSVC). PowerShell required for scripts.

Web: Python 3 (used by emsdk). The Emscripten SDK is bundled as a submodule.

Checking out

git clone --recurse-submodules https://github.com/ricardobusta/harpia-game-engine.git

If you already cloned without submodules:

git submodule update --init --recursive

---

Desktop Build — macOS

1. Set up asset symlinks (run once after cloning):

./build_scripts/create_symlinks.sh

2. Build:

mkdir cmake-build-release && cd cmake-build-release
cmake .. -DCMAKE_BUILD_TYPE=Release
cmake --build . --parallel

Output: cmake-build-release/bin/

---

Desktop Build — Windows

1. Set up asset symlinks — open PowerShell as Administrator:

.\build_scripts\create_symlinks.ps1

2a. Build with MinGW:

mkdir cmake-build-release && cd cmake-build-release
cmake .. -DCMAKE_BUILD_TYPE=Release -G "MinGW Makefiles"
cmake --build . --parallel

2b. Build with Visual Studio 2022:

mkdir cmake-build-release && cd cmake-build-release
cmake .. -G "Visual Studio 17 2022" -A x64
cmake --build . --config Release

Output: cmake-build-release/bin/ (DLLs are copied automatically on Windows).

---

Web Build — macOS / Linux (Emscripten → itch.io)

1. Install emsdk (one-time):

./build_scripts/install_emsdk.sh

macOS SSL note: If you see a CERTIFICATE_VERIFY_FAILED error, the script handles it automatically via PYTHONHTTPSVERIFY=0 and the system cert bundle.

2. Build:

./build_scripts/build_web.sh

Output in cmake-build-web/bin/:

File	Description
Harpia.SampleGame.html	Open this in a browser to run the game
Harpia.SampleGame.js	Emscripten JavaScript glue
Harpia.SampleGame.wasm	WebAssembly binary
Harpia.SampleGame.data	Preloaded assets

3. Test locally (browsers block WebAssembly over file://):

./build_scripts/serve_web.sh
# Open http://localhost:8080/Harpia.SampleGame.html

4. Package for itch.io:

./build_scripts/package_web.sh

This creates itch_upload.zip in the project root. Upload it to itch.io and set the game kind to HTML. If the game doesn't load, enable SharedArrayBuffer in the itch.io embed options.

---

Web Build — Windows (Emscripten)

1. Install emsdk:

.\build_scripts\install_emsdk.ps1

2. Build (run from the project root in a shell where emsdk is active):

cd harpia\third_party\emsdk
.\emsdk_env.bat
cd ..\..\..
mkdir cmake-build-web
cd cmake-build-web
emcmake cmake .. -DCMAKE_BUILD_TYPE=Release
cmake --build . --parallel

3. Test locally:

cd cmake-build-web\bin
python -m http.server 8080
# Open http://localhost:8080/Harpia.SampleGame.html

---

Project Structure

harpia-game-engine/
├── harpia/                  # Engine library
│   ├── engine/
│   │   ├── audio/           # SDL3_mixer audio system
│   │   ├── core/            # Application loop, input, time
│   │   ├── game/            # Scene and object management
│   │   ├── rendering/       # OpenGL / WebGL rendering
│   │   └── structures/      # Public math types, string utils
│   └── third_party/         # Vendored dependencies
├── sample_game/             # Example game
│   └── assets/              # Shaders, textures, audio, models
└── build_scripts/
    ├── create_symlinks.sh   # macOS asset symlink setup
    ├── create_symlinks.ps1  # Windows asset symlink setup
    ├── install_emsdk.sh     # macOS/Linux emsdk install
    ├── install_emsdk.ps1    # Windows emsdk install
    ├── build_web.sh         # macOS/Linux web build
    └── package_web.sh       # macOS/Linux itch.io packaging

Dependencies (vendored as submodules)

Library	Purpose
SDL3	Windowing, input, audio backend
SDL3_mixer	Audio playback
SDL3_image	Texture loading
SDL3_ttf	Font rendering
GLM	Math (internal only)
GL3W	Desktop OpenGL loader (not used in web builds)
OpenFBX	FBX model loading
emsdk	Emscripten SDK for WebAssembly

---

Useful Links

Google Test

• https://google.github.io/googletest/primer.html

EMScripten

• https://emscripten.org/docs/introducing_emscripten/about_emscripten.html
• https://stackoverflow.com/questions/51868832/integrate-emscripten-in-clion/72578219#72578219
• https://gist.github.com/WesThorburn/00c47b267a0e8c8431e06b14997778e4

Lazy Foo'

Good old SDL tutorials — https://lazyfoo.net/tutorials/SDL/index.php

Math libs

• https://github.com/sgorsten/linalg/blob/main/linalg.h
• https://github.com/g-truc/glm