vtTrackball Class Reference
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Inheritance diagram for vtTrackball:

[legend]List of all members.

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Detailed Description

A Trackball is a navigation engine which can move a Camera (or any other Transform target) and move it around a center point based on mouse input.

You can set which combinations of mouse buttons and modifier keys will rotate, zoom and translate the target. The default is:

• Middle button: Rotate.
• Middle button with shift key: Zoom.

Public Member Functions
void	SetRadius (float fRadius)
float	GetRadius () const
void	SetRotateButton (int button, int modifier=0, bool bExact=true)
void	SetZoomButton (int button, int modifier=0, bool bExact=true)
void	SetTranslateButton (int button, int modifier=0, bool bExact=true)
void	SetZoomScale (float s)
void	SetRotScale (float s)
void	SetTransScale (float s)
void	SetDirection (float fTheta, float fPhi)
void	MoveDirection (float fTheta, float fPhi)
void	OnMouse (vtMouseEvent &event)
	Virtual handler, to catch mouse events, can be overridden by your engine class.
void	Eval ()

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Member Function Documentation

void vtTrackball::Eval (   )  [virtual]

Virtual handler, will be called every frame to do the work of the engine. You must override this if you want your engine to be useful. Reimplemented from vtEngine.

float vtTrackball::GetRadius (   )  const

Get the radius, the distance from the pivot point that the Trackball rotates around.

void vtTrackball::MoveDirection (  float  fTheta, float  fPhi )

Shift the direction the trackball is facing, by a given offset. Parameters: fTheta,fPhi  Polar coordinates for the target relative to the pivot point.

void vtTrackball::SetDirection (  float  fTheta, float  fPhi )

Set the direction the trackball is facing. Parameters: fTheta,fPhi  Polar coordinates for the target relative to the pivot point.

void vtTrackball::SetRadius (  float  fRadius  )

Set the radius, the distance from the pivot point that the Trackball rotates around.

void vtTrackball::SetRotateButton (  int  button, int  modifier = 0, bool  bExact = true )

Set the buttons and modifier keys that will cause the Trackball to rotate. Parameters: button  The button state (VT_LEFT, VT_RIGHT, and/or VT_MIDDLE) modifier  The modifier state (VT_SHIFT, VT_CONTROL, and/or VT_ALT) bExact  If true, then exactly this button must occur. Otherwise, any button state that includes this state will suffice.

void vtTrackball::SetRotScale (  float  s  )

Set the scale factor for rotation, which controls how fast the Trackball will spin its target.

void vtTrackball::SetTranslateButton (  int  button, int  modifier = 0, bool  bExact = true )

Set the buttons and modifier keys that will cause the Trackball to translate. Parameters: button  The button state (VT_LEFT, VT_RIGHT, and/or VT_MIDDLE) modifier  The modifier state (VT_SHIFT, VT_CONTROL, and/or VT_ALT) bExact  If true, then exactly this button must occur. Otherwise, any button state that includes this state will suffice.

void vtTrackball::SetTransScale (  float  s  )

Set the scale factor for translation, which controls how fast the Trackball will translate its target.

void vtTrackball::SetZoomButton (  int  button, int  modifier = 0, bool  bExact = true )

Set the buttons and modifier keys that will cause the Trackball to zoom. Parameters: button  The button state (VT_LEFT, VT_RIGHT, and/or VT_MIDDLE) modifier  The modifier state (VT_SHIFT, VT_CONTROL, and/or VT_ALT) bExact  If true, then exactly this button must occur. Otherwise, any button state that includes this state will suffice.

void vtTrackball::SetZoomScale (  float  s  )

Set the scale factor for zoom, which controls how fast the Trackball will zoom in/out.

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