Building your game

Give your project its own C++ code, and build it into a game you can run outside the editor.

Build, near the right end of the toolbar, has everything on this page.

Item	What it does
Generate Game Project...	Adds a C# or C++ project to your project folder. Once it exists, this becomes Open C# Project Folder or Open C++ Project Folder.
Build Game	Compiles that project into a game executable.
Package Game	Makes a standalone copy of the game to share. See Packaging a build.

This page covers C++; switch to C# at the top of the page.

Building from the editor is Windows-only for now.

Generate the C++ project

Save your project first, then choose Build › Generate Game Project... and pick C++. The editor adds a Source folder to your project and opens it (or opens it in Visual Studio, if Open in Visual Studio is ticked):

Projects/MyGame/
  MyGame.hypproject
  Source/
    CMakeLists.txt
    Game/
      MyGameGame.hpp
      MyGameGame.cpp
    Launcher/
      main.cpp

The names come from your .hypproject file's name. These files are yours to edit, and the editor won't overwrite them.

File	What's in it
Game/MyGameGame.hpp, .cpp	Your `Game` class. This is where your game's code goes.
Launcher/main.cpp	The executable's entry point. It starts the engine and creates your `Game`.
CMakeLists.txt	Builds the two above against the engine. Every `.cpp` and `.hpp` under `Game/` is picked up automatically.

Your Game class

The generated class overrides a few hooks from Game:

void MyGameGame::OnLaunch()
{
    Game::OnLaunch();

    HYP_LOG(Game, Info, "MyGameGame launched");

    StartSimulating();
}

void MyGameGame::OnUpdate(float delta)
{
    Game::OnUpdate(delta);
}

Function	When it's called
OnLaunch	Once, after the startup world has loaded.
OnUpdate	Every frame, with the time since the last frame.
OnInputEvent	For each input event. Returns `true` if something handled it.
BeforeConnectingToServer	When the game starts as a client, before it has joined a server.
BeforeContentLoaded, AfterContentLoaded	Either side of loading the startup world.

The last three drive a plain status screen (ShowStatus and HideStatus in the same file), so the window says "Loading...", "Connecting to..." or why it couldn't connect instead of sitting black. Swap it for your own loading and connect screens.

CodeGenTool doesn't run on game code yet, so HYP_CLASS() and friends aren't available here. The generated .cpp registers the class by hand; leave that block at the bottom of the file in place.

Build

Choose Build › Build Game. Compiler output goes to the Console, and you'll get a message box if the build fails.

The build needs Visual Studio, or the Visual Studio Build Tools, with:

The Desktop development with C++ workload.
C++ Clang tools for Windows. Not needed if you built the editor yourself with MSVC.
C++ CMake tools for Windows.

If something's missing, the editor tells you what and offers to install the Build Tools for you.

The result lands in your project's Binaries folder:

Projects/MyGame/
  Binaries/Windows/
    MyGame.exe
    MyGameGame.dll
    hyperion.dll
    Config/
  Build/Windows/
    Build.bat

MyGameGame.dll holds your game's code, and MyGame.exe is the launcher that loads it. The engine's own libraries and config are copied in next to them. Build.bat runs the same build outside the editor.

Run it

Run MyGame.exe. It loads your project's content straight from the project folder, so there's nothing to cook: save in the editor, and the next run has your changes.

By default the game starts in single player. The same executable also hosts and joins multiplayer games:

Command	What it does
`MyGame`	Single player
`MyGame --server`	A headless dedicated server
`MyGame --singleplayer=false --host=127.0.0.1`	Joins the server at that address

The single player default comes from Binaries/Windows/Config/GlobalConfig.json; anything you pass on the command line overrides it. More in Running a server.

In the editor

Once the game is built, the editor loads MyGameGame.dll when it opens your project, and play-in-editor runs your Game class.

There's no hot reload for C++. You can rebuild while the project is open, but the editor keeps using the build it loaded until you restart it.

A project that's been saved with your Game class needs its built game to open. If the editor reports that the game module isn't built, run Build/Windows/Build.bat in the project folder, then open the project again.