Castle Game EngineIntroduction Units Class Hierarchy Classes, Interfaces, Objects and Records Types Variables Constants Functions and Procedures Identifiers |
Class TX3DEvent
Unit
X3DFields
Declaration
type TX3DEvent = class(TX3DFieldOrEvent)
Description
X3D event.
Hierarchy
Overview
Methods
Properties
Description
Methods
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destructor Destroy; override; |
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procedure Parse(Lexer: TX3DLexer); |
This only reads (optional) "IS" clause of the event, as may occur in VRML nodeBodyStatement.
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procedure SaveToStream(Writer: TX3DWriter); override; |
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procedure Send(Field: TX3DField; const Time: TX3DTime); |
Send a value to event. For input fields, this is used by routes, scripts etc. to send an event to a field. For output fields, this is used by node itself to send event to routes, scripts etc.
Field must be non-nil, of class FieldClass.
The Field instance doesn't become owned in any way by the TX3DEvent. That is, it's the caller responsibility to free the Field instance at any comfortable time, possibly right after calling Send.
Overloaded versions without explicit Time parameter just take time from ParentNode.Scene.GetTime. If ParentNode is Nil (which should not happen with normal fields within nodes) or if ParentNode.Scene is Nil (which may happen only if events processing is not turned on, that is TCastleSceneCore.ProcessEvents is False ) then event is not send.
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procedure RemoveHandler(Handler: TX3DEventReceive); |
Safely remove a callback from OnReceive list.
Contrary to direct OnReceive.Remove call, this works correctly even if we're right now in the middle of this event's processing. In the latter case, the handler will be actually removed with some delay (when it's safe).
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function SendNeeded: boolean; |
Is anything actually listening on this events Send?
Sometimes, even preparing a value to Send is quite time-consuming (example: CoordinateInterpolator, where a long MFVec3f value has to be computer). Then checking SendNeeded is useful: if SendNeeded = False , you know that there's no point in preparing Value to send, because actually Send will do nothing.
For example, event out to which no ROUTE is connected, and no Script can listen to it.
For now, this simply returns whether any OnReceive callback is registered.
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Properties
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property InEvent: boolean read FInEvent; |
Is it "in" or "out" event ?
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property ParentExposedField: TX3DField
read FParentExposedField write FParentExposedField; |
If this event is an exposed event belonging to some field, this references parent field. Otherwise it's Nil .
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property OnReceive: TX3DEventReceiveList read FOnReceive; |
Notifications about receiving an item. For input fields, these are used by node itself to listen to events send to it. For output fields, these are used by routes, scripts to listen to events occuring.
All callbacks here are simply called by Send method.
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