The HOpCameraZoomBox class zooms the camera to a selected area. More...

#include <HOpCameraZoomBox.h>

Public Member Functions

virtual HBaseOperatorClone ()
bool EnforceMinCameraSize () const
bool GetLightFollowsCamera ()
virtual const char * GetName ()
 HOpCameraZoomBox (HBaseView *view, int DoRepeat=0, int DoCapture=1)
virtual int OnLButtonDblClk (HEventInfo &hevent)
virtual int OnLButtonUp (HEventInfo &hevent)
void SetEnforceMinCameraSize (bool enforceMinCameraSize)
void SetLightFollowsCamera (bool follow)
- Public Member Functions inherited from HOpConstructRectangle
 HOpConstructRectangle (HBaseView *view, int DoRepeat=0, int DoCapture=1, bool UseCenterMarker=true)
virtual int OnLButtonDown (HEventInfo &hevent)
virtual int OnLButtonDownAndMove (HEventInfo &hevent)
virtual int OnRButtonUp (HEventInfo &hevent)
- Public Member Functions inherited from HBaseOperator
int Capture ()
 Returns whether we are currently in mouse capture mode. See this class' constructor for a more detailed description of what this means. This method has been deprecated.
HPoint const GetFirstPoint ()
 Returns the initial selection point.
HPoint const GetNewPoint ()
 Returns the current selection point.
HBaseViewGetView ()
 Returns a pointer to the view that this operator is associated with.
 HBaseOperator (HBaseView *view, int DoRepeat=0, int DoCapture=1)
virtual int OnKeyDown (HEventInfo &hevent)
virtual int OnKeyUp (HEventInfo &hevent)
virtual int OnLRButtonDownAndMove (HEventInfo &hevent)
virtual int OnMButtonDblClk (HEventInfo &hevent)
virtual int OnMButtonDown (HEventInfo &hevent)
virtual int OnMButtonDownAndMove (HEventInfo &hevent)
virtual int OnMButtonUp (HEventInfo &hevent)
virtual int OnMouseMove (HEventInfo &hevent)
virtual int OnMouseWheel (HEventInfo &hevent)
virtual int OnNoButtonDownAndMove (HEventInfo &hevent)
virtual int OnRButtonDblClk (HEventInfo &hevent)
virtual int OnRButtonDown (HEventInfo &hevent)
virtual int OnRButtonDownAndMove (HEventInfo &hevent)
virtual int OnTimer (HEventInfo &hevent)
virtual int OnTouchesDown (HEventInfo &hevent)
virtual int OnTouchesMove (HEventInfo &hevent)
virtual int OnTouchesUp (HEventInfo &hevent)
virtual bool OperatorStarted ()
 Operator has been started if true, and has not been started if false.
int Repeat ()
 Returns whether the operation is repeatable. This method has been deprecated.
void SetFirstPoint (HPoint const &new_point)
 Sets the initial selection point.
void SetMapTouchesToMouseEvents (bool val)
 Touch Events are mapped to mouse events if true, and are not if false.
void SetNewPoint (HPoint const &new_point)
 Sets the current selection point.
void SetOperatorStarted (bool val)
 Operator has been started if true, and has not been started if false.
void SetView (HBaseView *new_view)
 Sets the view that this operator is associated with.

Protected Member Functions

void ComputeNewField (float &width, float &height, HPoint min, HPoint max, HPoint const &new_tar)
bool ComputeReasonableTarget (HPoint &new_tar, HPoint const &min, HPoint const &max, HPoint const &tar_orig)
- Protected Member Functions inherited from HBaseOperator
bool IsSpecialKey (HC_KEY key)

Protected Attributes

bool m_enforceMinCameraSize
bool m_LightFollowsCamera
- Protected Attributes inherited from HOpConstructRectangle
bool m_bRectangleExists
char m_pSavedColor [MVO_BUFFER_SIZE]
char m_pSavedVisibility [MVO_BUFFER_SIZE]
HPoint m_ptRectangle [2]
- Protected Attributes inherited from HBaseOperator
bool m_bMapTouchesToMouseEvents
 Indicates if touch events are mapped to mouse events.
bool m_bOpStarted
 Indicates whether the operator has already 'started'. More...
int m_doCapture
 Integer indicating whether to capture mouse on button down and release on button up. This parameter has been deprecated.
int m_doRepeat
 Integer indicating if the operator is repeatable . This parameter has been deprecated.
HPoint m_ptFirst
 Initial selection point.
HPoint m_ptNew
 Current selection point.
 The HOOPS view corresponding to this operator.
HCutGeometryVisibility m_TempCutGeometryVisibility
 stores original cut geometry visibility
HShadowMode m_TempShadowMode
 stores original shadow mode

Detailed Description

The HOpCameraZoomBox class zooms the camera to a selected area.

HOpCameraZoomBox utilizes the drawing functionality of HOpConstructRectangle to define a selection rectangle, and then extends HOpConstructRectangle::OnLButtonUp to calculate a zoom factor and direction.

The operation consists of the following steps:

  1. Left Button Down: Registers the first point of the selection rectangle.
  2. Left Button Down and Drag: Rubberbands the rectangle to desired dimensions.
  3. Left Button Up: The is viewpoint calculated, camera position changed and the operation ends.


Internally, this operator uses single-precision calculations. When using this operator in a scene with very large coordinates (such as GPS coordinates), you may experience irregular behavior due to precision errors. The issue arises when the size of the camera is very small relative to the distance of the geometry from the origin. When comparing a very large number to a very small number using single precision float math, the small number can effectively "disappear", leading to errors in calculations.

3DF provides a double-precision API to get around these issues, but the double-precision portion of the API does not extend to MVO operators. Therefore, to address the problem using this operator, you can set the m_enforceMinCameraSize flag to "false" using the SetEnforceMinCameraSize function.

Constructor & Destructor Documentation

◆ HOpCameraZoomBox()

HOpCameraZoomBox::HOpCameraZoomBox ( HBaseView view,
int  DoRepeat = 0,
int  DoCapture = 1 

Constructs an HOpCameraZoomBox object.

viewA pointer to an HBaseView object.
DoRepeatAn integer denoting whether this is a repeatable operator. This parameter has been deprecated.
DoCaptureAn integer denoting whether the mouse state should be captured, which means that all mouse events should be received after a mousedown, even if it leaves the window. This parameter has been deprecated.

Member Function Documentation

◆ Clone()

virtual HBaseOperator* HOpCameraZoomBox::Clone ( )

Creates a new operator which is a copy of the current operator. The user is responsible for deleting the newly created operator.

A pointer to the newly created HOpCameraZoom object.

Reimplemented from HOpConstructRectangle.

◆ EnforceMinCameraSize()

bool HOpCameraZoomBox::EnforceMinCameraSize ( ) const

Returns the current 'EnforceMinCameraSize' setting.

◆ GetLightFollowsCamera()

bool HOpCameraZoomBox::GetLightFollowsCamera ( )
True if the light follows the camera or false if it doesn't.

◆ GetName()

virtual const char* HOpCameraZoomBox::GetName ( )
A pointer to a character string denoting the name of the operator which is 'HOpCameraZoomBox'.

Reimplemented from HOpConstructRectangle.

◆ OnLButtonDblClk()

virtual int HOpCameraZoomBox::OnLButtonDblClk ( HEventInfo hevent)

OnLButtonDblClk points the camera at the location where the mouse is double clicked.

heventAn HEventInfo object containing information about the current event.
An HOperatorReturn indicating the status of the event.

Reimplemented from HBaseOperator.

◆ OnLButtonUp()

virtual int HOpCameraZoomBox::OnLButtonUp ( HEventInfo hevent)

OnLButtonUp passes rectangle information from HOpConstructRectangle to the HOOPS routine #HC_Compute_Selection_By_Area, then uses the information from the selection list to move the camera and point it in the right direction.

heventAn HEventInfo object containing information about the current event.
An HOperatorReturn indicating the status of the event.

Reimplemented from HOpConstructRectangle.

◆ SetEnforceMinCameraSize()

void HOpCameraZoomBox::SetEnforceMinCameraSize ( bool  enforceMinCameraSize)

Specifies whether the zoom calculation should attempt to prevent camera field from becoming too small. This mode is enabled by default.

◆ SetLightFollowsCamera()

void HOpCameraZoomBox::SetLightFollowsCamera ( bool  follow)

SetLightFollowsCamera sets the lights to follow the camera or to stay in one place during orbit. This has the effect of either lighting the scene during orbit or allowing the camera to move through shadow. The default is off.

followPass true to have the light follow the camera.

The documentation for this class was generated from the following file: