77 lines
3.2 KiB
Plaintext
77 lines
3.2 KiB
Plaintext
//C++ header - Open Scene Graph - Copyright (C) 1998-2002 Robert Osfield
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//Distributed under the terms of the GNU Library General Public License (LGPL)
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//as published by the Free Software Foundation.
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#ifndef OSGGA_GUIACTIONADAPTER
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#define OSGGA_GUIACTIONADAPTER 1
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#include <osgGA/Export>
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namespace osgGA{
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/**
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Abstract base class defining the interface by which GUIEventHandlers may request
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actions of the GUI system in use. These requests for actions should then be honoured
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by the GUI toolkit of the user's application.
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To provide more detail, when a GUIEventHandler (e.g. a TrackballManipulator)
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handles an incoming event, such as a mouse event, it may wish to make
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a request of the GUI. E.g. if a model is 'thrown', the trackball manipulator
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may wish to start a timer, and be repeatedly called, to continuously refresh the
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camera's position and orientation. However, it has no way of doing this, as it
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knows nothing of the window system in which it's operating. Instead, the
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GUIEventHandler issues it's request via a GUIActionAdapter, and the viewer
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in use should honour the request, using the GUI system in play.
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There is more than one way of using the GUIActionAdapter. E.g. it may be inherited
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into a Viewer class, as is done with osgGLUT::Viewer. Alternatively, a simple
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subclass of GUIActionAdapter (e.g. osgQt::QtActionAdapter) may be passed to
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the GUIEventHandler::handle() function; once the function has returned, the viewer
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will then unpack the results and work out what to do to respond to the
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requests.
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Also there are several ways to run your app and handle the updating of
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the window. osgGLUT::Viewer always has a idle callback registered which does a
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redraw all the time. osgGLUT::Viewer can safely ignore both requestRedraw() and
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requestContinousUpdate() as these are happening all the time anyway.
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Other apps will probably want to respond to the requestRedraw() and
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requestContinousUpdate(bool) and again there is more than one way to handle it.
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You can override requestRedraw() and implement to call your own window
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redraw straight away. Or you can implement so that a flag is set and
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then you then respond the flag being set in your own leisure.
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*/
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class GUIActionAdapter
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{
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public:
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/**
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requestRedraw() requests a single redraw.
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*/
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virtual void requestRedraw() = 0;
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/**
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requestContinousUpdate(bool) is for en/disabling a throw or idle
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callback to be requested by a GUIEventHandler (typically a CameraManipulator,
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though other GUIEventHandler's may also provide functionality).
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GUI toolkits can respond to this immediately by registering an idle/timed
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callback, or can delay setting the callback and update at their own leisure.
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*/
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virtual void requestContinuousUpdate(bool needed=true) = 0;
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/**
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requestWarpPointer(int,int) is requesting a repositioning of the mouse pointer
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to a specified x,y location on the window. This is used by some camera manipulators
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to initialise the mouse pointer when mouse position relative to a controls
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neutral mouse position is required, i.e when mimicking a aircrafts joystick.
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*/
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virtual void requestWarpPointer(int x,int y) = 0;
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};
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}
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#endif
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