GluonEngine::Component Class Reference

Adds functionality to GameObjects, is the final level in the GameObject hierarchy. More...

#include <component.h>

Inheritance diagram for GluonEngine::Component:

Public Member Functions
Q_INVOKABLE	Component (QObject *parent=0)
	Component (const Component &other, QObject *parent=0)
	~Component ()
virtual QString	category () const
virtual QVariant	toVariant (GluonObject *wrapThis)
virtual void	initialize ()
virtual void	start ()
virtual void	update (int elapsedMilliseconds)
virtual void	draw (int timeLapse=0)
virtual void	stop ()
virtual void	cleanup ()
QString	description () const
void	setDescription (const QString &newDescription)
bool	enabled () const
void	setEnabled (bool newEnabled)
GameObject *	gameObject ()
void	setGameObject (GameObject *newGameObject)
void	sanitize ()
virtual QString	stringFromProperty (const QString &propertyName, const QString &indentChars) const
Properties
QString	description
bool	enabled

Detailed Description

Adds functionality to GameObjects, is the final level in the GameObject hierarchy.

Component is a class which defines the required functionality for implementing components for use with Gluon. A component is the place where the vast majority of logic found in GluonEngine games exist. The six most important functions for users are the virtual initialize(), start(), update(), draw(), stop() and cleanup() functions. This class is the final step in the GameObject hierarchy.

Since a component is attached to exactly one GameObject, the position in the world and anything else related to the GameObject can be found by accessing gameObject() (for example finding other Components and such)

Implementation checklist:

Inherit from GluonEngine::Component
- Add the GLUON_OBJECT macro to your class' header
  - Implement using QSharedData since GameObjects can be duplicated and the Components attached to it get duplicated along with it http://doc.trolltech.com/qshareddata.html
    - Expose any properties to be visible in the editor through Q_PROPERTY

Definition at line 61 of file component.h.

Constructor & Destructor Documentation

Component::Component ( QObject * parent = 0 )

Definition at line 33 of file component.cpp.

Component::Component	(	const Component &	other,
		QObject *	parent = `0`
	)

Definition at line 39 of file component.cpp.

Component::~Component ( )

Definition at line 45 of file component.cpp.

Member Function Documentation

QString Component::category ( ) const [virtual]

Return the category of the component. Meta-data used for filtering and sorting components

Reimplemented in GluonEngine::SoundEmitterComponent, GluonEngine::SoundListenerComponent, GluonEngine::CameraControllerComponent, GluonEngine::DiscRendererComponent, GluonEngine::DiscSectionRendererComponent, GluonEngine::SpriteRendererComponent, GluonEngine::TextRendererComponent, GluonEngine::KeyboardInputComponent, GluonEngine::MouseInputComponent, GluonEngine::TouchInputComponent, GluonEngine::QtScriptComponent, GluonEngine::SphereCollisionComponent, and GluonEngine::ScriptingComponent.

Definition at line 50 of file component.cpp.

virtual void GluonEngine::Component::cleanup ( ) [inline, virtual]

The cleanup function is called whenever an object is no longer needed. This happens mostly during scene changes.

Reimplemented in GluonEngine::SoundEmitterComponent, GluonEngine::CameraControllerComponent, GluonEngine::DiscRendererComponent, GluonEngine::DiscSectionRendererComponent, GluonEngine::SpriteRendererComponent, GluonEngine::TextRendererComponent, GluonEngine::QtScriptComponent, and GluonEngine::ScriptingComponent.

Definition at line 143 of file component.h.

QString GluonEngine::Component::description ( ) const

The description of the Component instance. An arbitrary value used to tell other members of the game development team what the Component is used for.

Returns:: The description of the Component instance

See also:: setDescription

void Component::draw ( int timeLapse = 0 ) [virtual]

The draw function is run every time the engine requests a redraw of the screen. Avoid putting any game logic in this function. The optional timeLapse depends on gameloop being used. By default Gluon uses a gameloop which runs update a fixed number of times per second, while draw is called as often as it can be. The timeLapse parameter then tells you how many milliseconds have passed since the last time update was run. This allows you to extrapolate draw positions of items and thus create a potentially smoother gaming experience.

Parameters:

timeLapse

The number of milliseconds passed since the last update

See also:: Game::runGame, update

Reimplemented in GluonEngine::SoundEmitterComponent, GluonEngine::SoundListenerComponent, GluonEngine::CameraControllerComponent, GluonEngine::DiscRendererComponent, GluonEngine::DiscSectionRendererComponent, GluonEngine::SpriteRendererComponent, GluonEngine::TextRendererComponent, GluonEngine::QtScriptComponent, and GluonEngine::ScriptingComponent.

Definition at line 73 of file component.cpp.

bool GluonEngine::Component::enabled ( ) const

Whether or not the Component is enabled for use by the GameObject it is contained within.

Returns:: True if the Component is enabled, false if not

See also:: setEnabled

GameObject * Component::gameObject ( )

Returns a pointer to the GameObject instance this instance of the Component is attached to. Use this for example to get the position or rotation relevant to the Component, or any other functionality found on GameObject (such as finding other Components)

Returns:: A pointer to the GameObject instance this Component is attached to

See also:: setGameObject, GameObject

Definition at line 126 of file component.cpp.

virtual void GluonEngine::Component::initialize ( ) [inline, virtual]

The initialize function is called whenever an initialized object is needed. This includes scene changes.

Reimplemented in GluonEngine::SoundEmitterComponent, GluonEngine::CameraControllerComponent, GluonEngine::DiscRendererComponent, GluonEngine::DiscSectionRendererComponent, GluonEngine::SpriteRendererComponent, GluonEngine::TextRendererComponent, GluonEngine::KeyboardInputComponent, GluonEngine::MouseInputComponent, GluonEngine::TouchInputComponent, GluonEngine::QtScriptComponent, and GluonEngine::ScriptingComponent.

Definition at line 99 of file component.h.

void Component::sanitize ( ) [virtual]

Function used on instantiation to fix the parent/child relationship. Used specifically by GDLHandler in the parseGDL() function. If you do not work on GDLHandler, it is unlikely you will need this function.

See also:: GDLHandler::parseGDL

Reimplemented from GluonCore::GluonObject.

Definition at line 79 of file component.cpp.

void Component::setDescription ( const QString & newDescription )

Set the description of the Component

Parameters:

newDescription

The new description

Definition at line 102 of file component.cpp.

void Component::setEnabled ( bool newEnabled )

Set the enabled parameter of the Component instance

Parameters:

newEnabled

The new value for the parameter

See also:: enabled

Definition at line 114 of file component.cpp.

void Component::setGameObject ( GameObject * newGameObject )

Move this Component to another GameObject. Please note that this will remove the Component from its current GameObject!

Parameters:

newGameObject

The GameObject instance to move this Component onto

See also:: gameObject, GameObject

Definition at line 132 of file component.cpp.

virtual void GluonEngine::Component::start ( ) [inline, virtual]

The start function is run once after each scene change, immediately before the first update

See also:: Game::setCurrentScene, update

Reimplemented in GluonEngine::SoundEmitterComponent, GluonEngine::SoundListenerComponent, GluonEngine::CameraControllerComponent, GluonEngine::DiscRendererComponent, GluonEngine::DiscSectionRendererComponent, GluonEngine::SpriteRendererComponent, GluonEngine::TextRendererComponent, GluonEngine::KeyboardInputComponent, GluonEngine::MouseInputComponent, GluonEngine::TouchInputComponent, GluonEngine::QtScriptComponent, GluonEngine::SphereCollisionComponent, and GluonEngine::ScriptingComponent.

Definition at line 105 of file component.h.

virtual void GluonEngine::Component::stop ( ) [inline, virtual]

The stop function is run once when the gameloop is stopped. Use it for removing temporary data between runs. Reimplement this function if you have something that needs cleaning up between runs.

Reimplemented in GluonEngine::SoundEmitterComponent, GluonEngine::KeyboardInputComponent, GluonEngine::MouseInputComponent, GluonEngine::TouchInputComponent, GluonEngine::QtScriptComponent, GluonEngine::SphereCollisionComponent, and GluonEngine::ScriptingComponent.

Definition at line 137 of file component.h.

QString Component::stringFromProperty	(	const QString &	propertyName,
		const QString &	indentChars
	)			const `[virtual]`

Adapted function which special cases access to properties with the type GluonEngine::Asset* - used by GDLHandler.

Parameters:

propertyName

The name of the property you wish to get in GDL property string form

Parameters:

indentChars

The characters used for indenting the string

Returns:: The GDL representation of the property

Reimplemented from GluonCore::GluonObject.

Definition at line 138 of file component.cpp.

virtual QVariant GluonEngine::Component::toVariant ( GluonObject * wrapThis ) [virtual]

If you wish to be able to use your objects as properties, make sure to implement this function to return a QVariant which is of the type of your class.

void Component::update ( int elapsedMilliseconds ) [virtual]

The update function is run each time the game logic needs to be updated. Implement this function in inherited classed to allow for updates along with the rest of the GameObject hierarchy. Note that this is only for updating the game logic - any drawing functionality should be put into the draw function.

Parameters:

elapsedMilliseconds

The amount of time in milliseconds which has passed since the last update