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/*=========================================================================
Program: Visualization Toolkit
Module: vtkScenePicker.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/**
* @class vtkScenePicker
* @brief Picks an entire viewport at one shot.
*
* The Scene picker, unlike conventional pickers picks an entire viewport at
* one shot and caches the result, which can be retrieved later.
* The utility of the class arises during <b>Actor Selection</b>. Let's
* say you have a couple of polygonal objects in your scene and you wish to
* have a status bar that indicates the object your mouse is over. Picking
* repeatedly every time your mouse moves would be very slow. The
* scene picker automatically picks your viewport every time the camera is
* changed and caches the information. Additionally, it observes the
* vtkRenderWindowInteractor to avoid picking during interaction, so that
* you still maintain your interactivity. In effect, the picker does an
* additional pick-render of your scene every time you stop interacting with
* your scene. As an example, see Rendering/TestScenePicker.
*
* @warning
* - Unlike a vtkHoverWidget, this class is not timer based. The hover widget
* picks a scene when the mouse is over an actor for a specified duration.
* - This class uses a vtkHardwareSelector under the hood. Hence, it will
* work only for actors that have opaque geomerty and are rendered by a
* vtkPolyDataMapper.
*
* @sa
* vtkHoverWidget vtkHardwareSelector
*/
#ifndef vtkScenePicker_h
#define vtkScenePicker_h
#include "vtkObject.h"
#include "vtkRenderingCoreModule.h" // For export macro
class vtkRenderer;
class vtkProp;
class vtkHardwareSelector;
class vtkRenderWindowInteractor;
class vtkScenePickerSelectionRenderCommand;
class VTKRENDERINGCORE_EXPORT vtkScenePicker : public vtkObject
{
friend class vtkRenderer;
friend class vtkScenePickerSelectionRenderCommand;
public:
static vtkScenePicker* New();
vtkTypeMacro(vtkScenePicker, vtkObject);
void PrintSelf(ostream& os, vtkIndent indent) override;
//@{
/**
* Set the renderer. Scene picks are restricted to the viewport.
*/
virtual void SetRenderer(vtkRenderer*);
vtkGetObjectMacro(Renderer, vtkRenderer);
//@}
/**
* Get cell id at the pick position.
* Returns -1 if no cell was picked.
* Makes sense only after Pick has been called.
*/
vtkIdType GetCellId(int displayPos[2]);
/**
* Get cell id at the pick position.
* Returns -1 if no cell was picked.
* Makes sense only after Pick has been called.
*/
vtkIdType GetVertexId(int displayPos[2]);
/**
* Get actor at the pick position.
* Returns NULL if none.
* Makes sense only after Pick has been called.
*/
vtkProp* GetViewProp(int displayPos[2]);
//@{
/**
* Vertex picking (using the method GetVertexId()), required
* additional resources and can slow down still render time by
* 5-10%. Enabled by default.
*/
vtkSetMacro(EnableVertexPicking, vtkTypeBool);
vtkGetMacro(EnableVertexPicking, vtkTypeBool);
vtkBooleanMacro(EnableVertexPicking, vtkTypeBool);
//@}
protected:
vtkScenePicker();
~vtkScenePicker() override;
// Pick render entire viewport
// Automatically invoked from vtkRenderer at the end of a still render.
void PickRender();
// Pick render a region of the renderwindow
void PickRender(int x0, int y0, int x1, int y1);
// Internal update method retrieves info from the Selector
void Update(int displayPos[2]);
// The RenderWindowInteractor must be set, so that avoid scene picks (which
// involve extra renders) during interaction. This is done by observing the
// RenderWindowInteractor for start and end interaction events.
void SetInteractor(vtkRenderWindowInteractor*);
vtkTypeBool EnableVertexPicking;
vtkHardwareSelector* Selector;
vtkRenderer* Renderer;
vtkRenderWindowInteractor* Interactor;
vtkIdType VertId;
vtkIdType CellId;
vtkProp* Prop;
bool NeedToUpdate;
int LastQueriedDisplayPos[2];
vtkScenePickerSelectionRenderCommand* SelectionRenderCommand;
vtkTimeStamp PickRenderTime;
private:
vtkScenePicker(const vtkScenePicker&) = delete;
void operator=(const vtkScenePicker&) = delete;
};
#endif