@node Games and Scenes
@chapter Games and Scenes

In Sly, games are defined declaratively. Game objects define
things such as the title and screen resolution. Games are composed of
many scenes, which encapsulate a particular aspect of the
game. Examples would be a main menu, a world map, or a battle screen.

@menu
* Games::
* Scenes::
@end menu

@node Games
@section Games

@anchor{2d game make-game}@defun make-game [#:title] [#:resolution] [#:fullscreen] [#:first-scene]
Return a new game.  All game properties have some reasonable default
value.

@end defun

@anchor{2d game define-game}@defspec define-game name kwargs ...
Syntactic sugar over define and make-game.

@end defspec

@anchor{2d game game?}@defspec game?
@end defspec

@anchor{2d game game-first-scene}@defspec game-first-scene
@end defspec

@anchor{2d game game-fullscreen?}@defspec game-fullscreen?
@end defspec

@anchor{2d game game-resolution}@defspec game-resolution
@end defspec

@anchor{2d game game-title}@defspec game-title
@end defspec

@anchor{2d game run-game}@defun run-game game
Open a window and start the game loop for GAME.

@end defun

@node Scenes
@section Scenes

@anchor{2d game make-scene}@defun make-scene [#:title] [#:events] [#:update] [#:draw] [#:state]
Return a new scene.  TITLE is a human readable name for the scene.
EVENTS is an alist of event handlers.  UPDATE is a procedure that
updates the scene.  DRAW is a procedure that renders the scene.  STATE
is an object that encapsulates the scene state.

@end defun

@anchor{2d game define-scene}@defspec define-scene name kwargs ...
Syntactic sugar over define and make-scene.  Return a procedure that
creates a new scene.

@end defspec

@anchor{2d game scene?}@defspec scene?
@end defspec

@anchor{2d game scene-draw-proc}@defspec scene-draw-proc
@end defspec

@anchor{2d game scene-observer}@defspec scene-observer
@end defspec

@anchor{2d game scene-state}@defspec scene-state
@end defspec

@anchor{2d game scene-title}@defspec scene-title
@end defspec

@anchor{2d game scene-update-proc}@defspec scene-update-proc
@end defspec

@anchor{2d game current-fps}@defun current-fps
Return the current FPS value.

@end defun

@anchor{2d game default-scene-events}@defun default-scene-events
@end defun

@anchor{2d game draw-scene}@defun draw-scene scene
Draw SCENE.

@end defun

@anchor{2d game pop-scene}@defun pop-scene
Exit the current scene and resume the previous scene.  If there is no
previous scene, the game loop will terminate.

@end defun

@anchor{2d game push-scene}@defun push-scene scene
Pause the current scene and start SCENE upon next game tick.

@end defun

@anchor{2d game replace-scene}@defun replace-scene scene
@end defun

@anchor{2d game scene-trigger}@defun scene-trigger scene event-type . args
Trigger an event on the scene observer.

@end defun

@anchor{2d game update-scene}@defun update-scene scene
Update SCENE.

@end defun