Table of Contents

About the sample

This sample is a minimal Game DLL implementation meant to showcase how a game project can be built using only C++ code, as opposed to combining C++ with C# and / or Lua.

The sample implements the following:

• Animated Entity - Basic entity that with the help of editor properties can play raw animations (Does not use Mannequin!)
• Environment Probe - Native implementation of an environment probe, normally loaded via Lua in the GameSDK and GameZero projects.
• Physicalized Entity - Native entity implementation that allows physicalizing a specified model as a rigid or static entity.

Code Breakdown

Startup

1. The Launcher application (see <engine root>/Code/Launcher/WindowsLauncher/ for an example) loads the sample Game DLL and invokes the external 'CreateGameStartup' function.
2. The sample function CreateGameStartup in <sample root>/Code/Game/GameDll/Main.cpp is invoked and calls CGameStartup::Create, resulting in the CGameStartup instance being created.
3. The Launcher application calls IGameStartup::Init, which in turn initializes the engine and its modules.
   • This function is responsible for initializing the Game Framework (contained in CryAction.dll), which in turn initializes the engine via the CrySystem module.
4. The Launcher then calls IGameStartup::Run, invoking the main game loop that runs until the engine is shut down.
   • This function largely delegates the actual process of updating to the IGame implementation inside the game module, which in turn calls IGameFramework::PreUpdate and IGameFramework::PostUpdate in order to start the engine update and render flow.

Entities

Entities in the sample all implement the CNativeEntityBase helper, a class that in turn implements ISimpleExtension and IGameObjectExtension in order to expose a few helper methods for setting and getting Entity properties that can be manipulated via the Sandbox Editor's Properties panel. The sample also implements a custom IEntityPropertyHandler implementation (instantiated once per entity class) in order to provide support for pure C++ entities. Without this, entities need a Lua script in order to expose properties to designers.

Each entity is registered in <sample root>/Code/Game/GameDll/Game/GameFactory.cpp, inside the CGameFactory::Init function. The entity being registered can specify any number of entity properties and then register using CGameFactory::RegisterNativeEntity in order to have the engine recognize and expose the entity to designers.

Dummy Player

The "Player" in this sample is merely a dummy entity automatically spawned at the center of the map in CGameRules::OnClientConnect (called shortly after level load). The entity has no responsibility barring a manual update of the view camera position each frame to match the entity position.