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You.i Engine
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You.i Engine
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Events and event dispatching.
You.i Engine's event system is based on the W3C Dom Level 3 events standard.
The CYIApp instance generates and dispatches most of the events that are dealt with. Events that users are typically interested in are touch and move events (CYIActionEvent), key input events (CYIKeyEvent) and trackpad events (CYITrackpadEvent).
When user input is detected by the CYIApp instance, one or more corresponding events are generated and broadcast. The object which receives the events depends on the event type, and on which object are registered as events listener.
For CYIActionEvent, a CYIRay is generated at the screen coordinates specified in the event. The ray is then transformed into the scene nodes' local space to find the scene node that should receive the event. This node is called the event target. The Capture phase of the event system is then initiated. Starting at the root node of the scene tree, the ancestors of the event target are traversed one by one. This gives ancestors the opportunity to 'capture' the event from the event target by setting the CYIEvent::bStopPropagation flag to true. If the propagation isn't stopped, the event is then given to the event target to process. Again, the event target can stop propagation by setting CYIEvent::bStopPropagation to true. Once processed by the event target, and if the propagation hasn't been stopped, the ancestors of the event target are traversed again but starting at the event target and going towards the root node. This last traversal is called the Bubble phase.
For CYIKeyEvent and CYITrackpadEvent, only the scene node that has been registered as capturing events receives the event. This registration is done using the CYISceneNode::StartCaptureKeyboardEvents() and CYISceneNode::StartCaptureTrackpadEvents() functions. While a pick ray is not used to determine the event target, the Capture and Bubble phases are still performed for key and trackpad events.
There are multiple event classes used in You.i Engine, all having CYIEvent as the base class. There exist functions on the CYIEvent class which can be used to determine, at runtime, what class an event is. Additionally, the YI_EVENT_TYPE enum lists various subtypes that each event can be. For example, the CYIKeyEvent class can be of type YI_KEY_DOWN, YI_KEY_UP or YI_KEY_INPUT. It is often desirable to check the event's type in a scene node's CYIEventHandler::HandleEvent() function.
Namespaces | |
| yi::deprecated | |
| Deprecated classes. | |
Classes | |
| class | CYIActionEvent |
| Stores data related to a user Action event. More... | |
| class | CYIAbstractDeferredDeletionEvent |
| Abstract event for handling deferred deletion of data. More... | |
| class | CYIDeferredDeletionEvent< YI_TYPE, SfinaeHelper > |
| Event for handling deferred deletion of data of type YI_TYPE. SfinaeHelper type is used to control a partial-specialization for CYISceneNode, to ensure the CYISceneNode is removed from it's parent in the scenetree. More... | |
| class | CYIDeferredDeletionEventHandler |
| Handles events where data deletion needs to be deferred. More... | |
| class | CYIEvent |
| Base class for events. More... | |
| class | IYIEventDispatcherListener |
| Implementors of this Listener interface can register themselves with the CYIEventDispather and become Observers of various event dispatching actions. More... | |
| class | CYIEventDispatcher |
| Stores, queues and dispatches events as well as sending notifications to IYIEventDispatcherListener objects regarding different actions being taken on the events. More... | |
| class | CYIEventFilter |
| Allows children that inherit from this class to implement processing before and after events are handled. More... | |
| class | CYIEventFilterProxy |
| Proxy for a CYIEventFilter allowing safe destruction of the internal event filter objects. More... | |
| class | CYIEventHandler |
| Allows registering of event filters which can be used to perform processing on an event before and after the event has been handled and/or dispatched. More... | |
| class | CYIEventHandlerProxy |
| Proxy for a CYIEventHandler allowing safe destruction of the internal event handler objects. More... | |
| class | CYIEventTarget |
| Represents an event target of type YI_SPECIAL_EVENT_TARGET_TYPE. More... | |
| class | CYIFocusEvent |
| Focus events represent when a view receives or loses focus. More... | |
| class | CYIKeyEvent |
| Class for key events. More... | |
| class | CYIRay |
| Encapsulates the origin and direction points of a ray. More... | |
| class | CYITaskEvent |
| Event class containing CYITaskBase items. Supports the task being executed when the event is handled. More... | |
| class | CYITaskEventHandler |
| Handles events where tasks are executed when the event is processed on an event queue. More... | |
| class | CYITrackpadEvent |
| Stores data related to trackpad input. More... | |
Functions | |
| template<typename YI_TYPE > | |
| void | YiDeleteLater (std::unique_ptr< YI_TYPE > pPtr) |
| Adds the given pointer to the deferred deletion queue. More... | |
| enum YI_ASCII_CODE |
Ascii codes for key characters.
| enum YI_EVENT_PHASE |
The current processing phase of the event.
| enum YI_EVENT_PRIORITY |
| enum YI_EVENT_TYPE |
The event type of the CYIEvent class instance.
| enum YI_KEY_CODE |
Key code for CYIKeyEvent events.
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inline |
Adds the given pointer to the deferred deletion queue.
The data is passed in a
1.8.11