Semantic Pointing for Object Picking in Complex 3D Environments This file is responsible the non-opengl related calculations in our implementation. More...

#include <PickingHelper.hpp>

Public Member Functions
	~PickingHelper ()
	PickingHelper class destructor.

void	checkNN (const GLint *pickbuffer_window, const int x_size, const int y_size, const int x_center, const int y_center, int &id, double &distance)
	Searches pickbuffer window for nearest objects and returns the nearest objects ID and its euclidean distance to the mouse cursor. More...

double	scale_by_distance (double distance)
	Scaling function Calls either mouse_scale_linear or mouse_scale_inverse and returns the scale factor. More...

double	springInput (double lastValue, double targetValue, double deltaTime, double springConstant)
	Uses Spring function to smooth out input. More...

double	changeCutoffDistance (double deltaC)
	Use this method to safely change the Cutoff - distance required for the linear scaling function. More...

double	changeMinScale (double delta_m)
	Use this method to safely change the minumum value of the scale function interval. More...

double	changeMaxScale (double delta_M)
	Use this method to safely change the maximum value of the scale function interval. More...

double	changeInverseExponent (double delta_S)
	Use this method to safely change the exponent of the inverse scale function. More...

bool	toggleNaiveSearch ()
	Toggles between usage of the naive- and the sophicticated pickbuffer search algorithm. More...

bool	toggleLinearScaling ()
	Toggles between usage of the linear- and the inverse scaling function. More...

bool	toggleBubbleCursor ()
	Toggles wheather the bubble cursor should be displayed or the standard cursor. More...

void	togglePickbufferRectangle ()
	Toggles wheather the pickbuffer window should be displayed additionally.

Static Public Member Functions
static PickingHelper *	getInstance ()
	Use this to access the object instance. More...

Public Attributes
bool	m_useLinearScaling
	scaling function switch

bool	m_useNaiveSearch
	search algorithm switch

bool	m_showPickbufferRectangle
	pickbuffer rectangle visualization switch

bool	m_showBubbleCursor
	bubble - / crosshair cursor switch

int	m_pickingbuffer_window_width
	Search width and height in pixel, assuming the window is quadratic.

Private Member Functions
	PickingHelper ()
	PickingHelper class constructor.

void	checkNN_sophisticated (const GLint *pickbuffer_window, const int x_size, const int y_size, const int x_center, const int y_center, int &id, double &distance)
	Searches pickbuffer window for nearest objects and returns the nearest objects ID and its euclidean distance to the mouse cursor. More...

void	checkNN_naive (const GLint *pickbuffer_window, const int x_size, const int y_size, const int x_center, const int y_center, int &id, double &distance)
	Searches pickbuffer window for nearest objects and returns the nearest objects ID and its euclidean distance to the mouse cursor. More...

double	mouse_scale_linear (double distance)
	Linear scaling function Returns a scaling factor based on the input euclidean distance. More...

double	mouse_scale_inverse (double distance)
	Inverse scaling function Returns a scaling factor based on the input euclidean distance. More...

Private Attributes
double	m_mouse_min_scale
	minimum scale function value

double	m_mouse_max_scale
	maximum scale function value

double	m_mouse_cutoff_distance
	Cutoff distance. More...

double	m_mouse_scaling_exponent
	exponent in inverse scaling function

Static Private Attributes
static PickingHelper *	singletonPointer = 0
	The singleton pointer.

Detailed Description

Semantic Pointing for Object Picking in Complex 3D Environments This file is responsible the non-opengl related calculations in our implementation.

Member Function Documentation

double PickingHelper::changeCutoffDistance ( double deltaC )

inline

Use this method to safely change the Cutoff - distance required for the linear scaling function.

Parameters

deltaC desired difference in cutoff distance.

Returns: the new value.

double PickingHelper::changeInverseExponent ( double delta_S )

inline

Use this method to safely change the exponent of the inverse scale function.

its range is limited by [0.1, 50.0]

See also: m_mouse_scaling_exponent

Parameters

delta_S desired difference in exponent.

Returns: the new value.

double PickingHelper::changeMaxScale ( double delta_M )

inline

Use this method to safely change the maximum value of the scale function interval.

its range is limited by [

See also: m_mouse_min_scale,; SCALE_MAX]

Parameters

delta_M desired difference in maximum interval.

Returns: the new value.

double PickingHelper::changeMinScale ( double delta_m )

inline

Use this method to safely change the minumum value of the scale function interval.

its range is limited by [ SCALE_MIN, m_mouse_max_scale]

See also: SCALE_MIN; m_mouse_max_scale

Parameters

delta_m desired difference in minimum interval.

Returns: the new value.

void PickingHelper::checkNN	(	const GLint *	pickbuffer_window,
		const int	x_size,
		const int	y_size,
		const int	x_center,
		const int	y_center,
		int &	id,
		double &	distance
	)

Searches pickbuffer window for nearest objects and returns the nearest objects ID and its euclidean distance to the mouse cursor.

This method calls one of the private members

See also: checkNN_naive or; checkNN_sophisticated, depending on the flag m_useNaiveSearch.

Parameters

pickbuffer_window	The pickbuffer window. It's supposed to contain object IDs > 0 whenever a pixel for a pickable object is drawn.
x_size	Absolute width of the pickbuffer window.
y_size	Absolute height of the pickbuffer window.
x_center	Absolute mouse cursor x-location relative to pickbuffer_window origin.
y_center	Absolute mouse cursor y-location relative to pickbuffer_window origin.
id	Stores the object ID of the nearest object. Will be 0 if no object is found.
distance	Stores the euclidean distance from the mouse cursor to the nearest object. Will be

See also: DBL_MAX if no object is found.

void PickingHelper::checkNN_naive	(	const GLint *	pickbuffer_window,
		const int	x_size,
		const int	y_size,
		const int	x_center,
		const int	y_center,
		int &	id,
		double &	distance
	)

private

Searches pickbuffer window for nearest objects and returns the nearest objects ID and its euclidean distance to the mouse cursor.

This is a naive implementation. It runs through all entries in the pickbuffer. Due to its simplicity it is very fast for small pickbuffer windows.

Parameters

pickbuffer_window	The pickbuffer window. It's supposed to contain object IDs > 0 whenever a pixel for a pickable object is drawn.
x_size	Absolute width of the pickbuffer window.
y_size	Absolute height of the pickbuffer window.
x_center	Absolute mouse cursor x-location relative to pickbuffer_window origin.
y_center	Absolute mouse cursor y-location relative to pickbuffer_window origin.
id	Stores the object ID of the nearest object. Will be 0 if no object is found.
distance	Stores the euclidean distance from the mouse cursor to the nearest object. Will be DBL_MAX

See also: DBL_MAX if no object is found.

void PickingHelper::checkNN_sophisticated	(	const GLint *	pickbuffer_window,
		const int	x_size,
		const int	y_size,
		const int	x_center,
		const int	y_center,
		int &	id,
		double &	distance
	)

private

Searches pickbuffer window for nearest objects and returns the nearest objects ID and its euclidean distance to the mouse cursor.

This implementation is a bit more sophisticated, than the naive approach. It searches for nearest objects by growing the search region starting from the mouse center until it hits an object. This will increase search performance, as long as objects are nearby.

Parameters

pickbuffer_window	The pickbuffer window. It's supposed to contain object IDs > 0 whenever a pixel for a pickable object is drawn.
x_size	Absolute width of the pickbuffer window.
y_size	Absolute height of the pickbuffer window.
x_center	Absolute mouse cursor x-location relative to pickbuffer_window origin.
y_center	Absolute mouse cursor y-location relative to pickbuffer_window origin.
id	Stores the object ID of the nearest object. Will be 0 if no object is found.
distance	Stores the euclidean distance from the mouse cursor to the nearest object. Will be DBL_MAX

See also: DBL_MAX if no object is found.

PickingHelper * PickingHelper::getInstance ( )

static

Use this to access the object instance.

Returns: The singleton object instance

double PickingHelper::mouse_scale_inverse ( double distance )

private

Inverse scaling function Returns a scaling factor based on the input euclidean distance.

See also: m_mouse_max_scale; m_mouse_min_scale; m_mouse_cutoff_distance; MOUSE_SCALING_CONSTANT

Parameters

distance euclidean distance.

Returns: scaling factor.

double PickingHelper::mouse_scale_linear ( double distance )

private

Linear scaling function Returns a scaling factor based on the input euclidean distance.

See also: m_mouse_max_scale; m_mouse_min_scale; m_mouse_cutoff_distance; MOUSE_SCALING_CONSTANT

Parameters

distance euclidean distance.

Returns: scaling factor.

double PickingHelper::scale_by_distance ( double distance )

Scaling function Calls either mouse_scale_linear or mouse_scale_inverse and returns the scale factor.

See also: m_mouse_cutoff_distance; MOUSE_SCALING_CONSTANT

Parameters

distance euclidean distance.

Returns: scaling factor in range [

See also: m_mouse_min_scale ,; m_mouse_max_scale].

double PickingHelper::springInput	(	double	lastValue,
		double	targetValue,
		double	deltaTime,
		double	springConstant = `6.0`
	)

Uses Spring function to smooth out input.

Spring Equation used: out = targetValue + (lastValue-targetValue)*exp(-deltaTime*springConstant);

Parameters

lastValue	the last value of teh variable.
targetValue	The target value to smooth out.
deltaTime	Time elapsed since last frame.
springConstant	Spring Constant. Is 6 by default

Returns: smoothed out value.

bool PickingHelper::toggleBubbleCursor ( )

inline

Toggles wheather the bubble cursor should be displayed or the standard cursor.

Returns: the boolean state.

bool PickingHelper::toggleLinearScaling ( )

inline

Toggles between usage of the linear- and the inverse scaling function.

Returns: the boolean state.

bool PickingHelper::toggleNaiveSearch ( )

inline

Toggles between usage of the naive- and the sophicticated pickbuffer search algorithm.

Returns: the boolean state.

Member Data Documentation

double PickingHelper::m_mouse_cutoff_distance

private

Cutoff distance.

If distance is higher than this threshold the maximum mouse scale factor will be output

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

C:/Users/Felix/Documents/TU/VIS2/vis2/src/TheVengefulHandOfGod/src/PickingHelper.hpp
C:/Users/Felix/Documents/TU/VIS2/vis2/src/TheVengefulHandOfGod/src/PickingHelper.cpp

Public Member Functions

Static Public Member Functions

Public Attributes

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Member Function Documentation

Member Data Documentation