Working with Scenes

Amphora uses the concept of scenes to manage game levels. At its most basic, a scene is simply a collection of three functions: an init function, an update function, and a destroy function. When a scene is loaded, its init function is run once, then its update function is run once per frame, and finally its destroy function is run when it's unloaded.

Creating a Scene

Scenes are managed using the scene_list.h file and the same X-macro pattern we've scene before. An example scene_list.h file could look as follows:

#define SCENES \
    SCENE(MainMenu) \
    SCENE(Level1) \
    SCENE(Level2) \
    SCENE(Level3)

Typically each scene will have its own file where its functions will reside. The functions require the following prototypes:

void {SceneName}_Init(void);
void {SceneName}_Update(Uint32, const InputState *);
void {SceneName}_Destroy(void);

Somewhere above the functions you will also need to include the following macro:

Amphora_BeginScene(name)

So a completed scene file for the MainMenu scene could look as so:

#include "engine/amphora.h"

Amphora_BeginScene(MainMenu)

MainMenu_Init(void) {}
MainMenu_Update(Uint32 frame, const InputState *input_state) {}
MainMenu_Destroy(void) {}

Loading Scenes

A scene is loaded using Amphora_LoadScene(name). This will call the current scene's destroy function, free other allocated resources, then call the new scene's init function and begin running its update function.

For example, to load level 1, it'd be as simple as:

Amphora_LoadScene("Level1");

07 March 2025