Documentation | Getting Started | Examples

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A cross-platform 2D game engine written in C++, designed for performance and ease of use. Astera combines modern rendering techniques with scripting flexibility to provide a comprehensive development environment for 2D games.

Architecture

• Entity Component System (ECS) - Flexible, composition-based entity management
• Cross-platform - Supports Windows and Linux
• OpenGL Rendering - Hardware-accelerated 2D graphics with sprite batching
• Lua Scripting - Full engine API exposed to Lua with complete type definitions

Getting Started

Prerequisites

• CMake 3.14 or higher
• C++20 compatible compiler
• OpenGL 4.6
• Lua >= 5.1

Building

1. Clone the repository:

git clone https://github.com/jakerieger/Astera.git
cd Astera

2. Install library dependencies:

Linux:

sudo apt install libfmt-dev \
  libspdlog-dev \
  libpugixml-dev \
  libcli11-dev \
  libglfw3-dev \
  libluajit-5.1-dev \
  libsndfile1-dev

Windows:

Important

Windows requires the use of vcpkg to install dependencies.

In the project root run this:

git clone https://github.com/microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg install pkgconf \
    fmt \
    spdlog \
    pugixml \
    cli11 \
    glfw3 \
    luajit \
    libsndfile \
    --triplet x64-windows

3. Build using CMake:

mkdir build
cd build
cmake ..
cmake --build .

Alternatively, use the provided build script:

lua build.lua

build.lua contains a lot of helpful commands. Run lua build.lua --help for a full list.

Examples

Lua Script Example

The following script demonstrates a basic entity controller with movement and audio:

--- BallController.lua
--- Movement controller with background music

ballSpeed = 500
bgMusicID = 1

function OnAwake(this)
    Log:Debug(string.format("OnAwake() called for entity: %s", this.name))

    if AudioPlayer:IsInitialized() then
        AudioPlayer:SetSoundVolume(bgMusicID, 0.5)
        AudioPlayer:PlaySound(bgMusicID, true)
    end
end

function OnUpdate(this, clock)
    local transform = this.transform
    local dT = clock:GetDeltaTime()
    local newPosition = Vec2(0, 0)

    if Input:GetKeyDown(KeyCode.W) then
        newPosition.y = ballSpeed * dT
    end
    if Input:GetKeyDown(KeyCode.S) then
        newPosition.y = -ballSpeed * dT
    end
    if Input:GetKeyDown(KeyCode.A) then
        newPosition.x = -ballSpeed * dT
    end
    if Input:GetKeyDown(KeyCode.D) then
        newPosition.x = ballSpeed * dT
    end

    transform:Translate(newPosition)
end

function OnDestroyed(this)
    Log:Debug(string.format("OnDestroyed() called for entity: %s", this.name))
end

Scene Definition Example

Scenes are defined using XML format:

<?xml version="1.0" encoding="UTF-8" ?>
<Scene name="Sandbox">
    <Entities>
        <Entity id="0" name="Ball">
            <Components>
                <Transform>
                    <Position x="640" y="360"/>
                    <Rotation x="0" y="0"/>
                    <Scale x="64" y="64"/>
                </Transform>
                <SpriteRenderer>
                    <Texture>ball.png</Texture>
                </SpriteRenderer>
                <Behavior>
                    <Script id="0">BallController.lua</Script>
                </Behavior>
                <Rigidbody2D>
                    <BodyType>Dynamic</BodyType>
                    <Mass>1.0</Mass>
                    <Restitution>0.5</Restitution>
                    <Friction>0.3</Friction>
                    <GravityScale>1.0</GravityScale>
                </Rigidbody2D>
            </Components>
        </Entity>
    </Entities>
</Scene>

Scene serialization is currently in development.

Documentation

Full API documentation is generated using Doxygen and hosted at: https://jakerieger.github.io/Astera/

Lua type definitions can be found in EngineContent/Scripts/types/ for IDE autocomplete support.

Development Status

Astera is an ongoing personal project and is provided as-is. The engine is functional but under active development. Features and APIs may change as the project evolves.

Current Status:

• Core engine systems functional
• Scripting API complete for basic 2D games
• Asset loading in original format only (no compression/packing yet)

Known Limitations:

• No built-in editor
• Asset pipeline requires manual organization
• Limited documentation coverage
• Scene format may change in future versions
• Mix of asserts and exceptions, consistent error handling is a work-in-progress

Contributing

While Astera is primarily a personal project, issue reports are welcome. However, please note that issues may not be addressed until the engine reaches an official release milestone.

License

Astera is licensed under the Apache License 2.0. See LICENSE for details.

Acknowledgments

See THIRD_PARTY.md for a list of third-party licenses for libraries used by Astera.

Contact

For questions or feedback, please open an issue on GitHub.

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Note: This is a work-in-progress project. Use at your own risk for production purposes.