The Scene class¶
The scene class wraps together game logic, asset loading draw calls & properties that all belong to one part of your game. A scene could be a menu screen, or a single game level, or a score board, or an intro video.
For an example on how to use the scene class in your game. See game.set_scene(scene)
This is a constructor function used for creating new scenes. Use it like this:
local scene = Scene("My Scene")
The first argument is optional, and is the display name of the scene, not to be confused with scene which is the variable name.
The examples below use
scene... to demonstrate various techniques. However
this assumes you have created a “scene” variable like the one above.
This property lets you get or set an optional display name of the scene.
on method allows you to subscribe to a named built-in or custom event. The
built in events are really useful as these allow you to hook in and control
scene game logic, drawing etc…
Here are some code examples for key events you should be aware of:
The init event¶
scene.on('init', function() -- do something here end)
init event is called when the scene is ready to start loading assets for
your scene. It can only be fired once, and it’s called when
used, however you can also trigger the event manually by using
The shown event¶
scene.on('shown', function(dt) -- do something here end)
As a scene can be shown more than once, an event called shown is made available to allow you to handle what happens when a specific scene is selected as the active one. If a previous scene was active, a hidden event is fired on the previous scene before hand.
The update event¶
scene.on('update', function(dt) -- do something here end)
update event is called to give your scene the opportunity to update game
logic. This callback provides a dt argument which is a float representing the
delta time since update was last called, useful for timing animations, or game logic.
The draw event¶
scene.on('draw', function() renderer.clear() renderer.begin() -- do something here renderer.present() end)
draw event is called to give your scene the opportunity to draw graphics
specific to the scene.
Trigger allows you to trigger custom events throughout your code. These events
can be handled by the
on method shown above. To trigger an event, simply write
something like this:
The first argument is the name of the event to trigger. The base trigger method does not support passing additional arguments.