VolVis::VolumeRendering::TransferFunction Class Reference

#include <TransferFunction.h>

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Detailed Description

Manages the nodes of a transfer function and creates the according texture. The transfer function is used to map density values to a color and an alpha value.

Public Member Functions
void	bindTexture () const
bool	editNode (int oldPos, int newPos, float newAlpha)
void	editNodeColor (int position, Eigen::Vector3f &color)
const std::map< int, TFNode >	getAllNodes () const
const TFNode &	getNode (int position) const
int	getResolution () const
GLuint	getTexture () const
bool	hasNode (int position) const
void	openFile (std::string &filePath)
bool	removeNode (int position)
void	saveToFile (std::string &filePath)
void	setNode (int position, Eigen::Vector3f &color, float alpha)
void	setNode (int position, TFNode &node)
	TransferFunction (int resolution=4096)
	~TransferFunction ()
Static Public Member Functions
static GLuint	getDisabledGradientTF ()
static GLuint	getDisabledIntensityTF ()

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Constructor & Destructor Documentation

VolVis::VolumeRendering::TransferFunction::TransferFunction

(

int

resolution = 4096

)

Constructor. Creates two nodes at the beginning and the end.

Parameters:

resolution

the resolution of the texture which applies the transfer function to the gpu. Should be power of two.

VolVis::VolumeRendering::TransferFunction::~TransferFunction

(

)

Destructor.

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Member Function Documentation

void VolVis::VolumeRendering::TransferFunction::bindTexture

(

)

const

bind the texture id containing the transfer function in openGL.

bool VolVis::VolumeRendering::TransferFunction::editNode	(	int	oldPos,
		int	newPos,
		float	newAlpha
	)

Moves a node of the transfer function. The position in the array and the alpha value are changed. The color stays constant. The position of the first and last node cannot be changed (but the alpha value is edited). A position cannot be changed to a lower/greater value than its neighbours'. If the node couldn't be found, nothing is done.

Parameters:

	oldPos	old position to identify the node
	newPos	the new position (x-value) of the node
	newAlpha	the new alpha value (y-value) of the node

Returns:

false if the position couldn't be changed.

void VolVis::VolumeRendering::TransferFunction::editNodeColor	(	int	position,
		Eigen::Vector3f &	color
	)

Edits the color of the node. All other parameters stay constant. If the node couldn't be found, nothing is done.

Parameters:

	position	position (x-value) to identify the node
	color	the new color of the node

const std::map<int, TFNode> VolVis::VolumeRendering::TransferFunction::getAllNodes

(

)

const

returns the map of all nodes

Returns:

map of all nodes defined by their positions (x-values).

static GLuint VolVis::VolumeRendering::TransferFunction::getDisabledGradientTF

(

)

[static]

Creates (if not already available) a small texture which transfers all gradient magnitude values to one, which is the same as if no gradient transfer function would be applied.

Returns:

texture id of disabled gradient transfer function

static GLuint VolVis::VolumeRendering::TransferFunction::getDisabledIntensityTF

(

)

[static]

Creates (if not already available) a small texture which transfers the intensity values from zero to one, which is the same as if the intensity values would be drawn directly.

Returns:

texture id of disabled intensity transfer function

const TFNode& VolVis::VolumeRendering::TransferFunction::getNode

(

int

position

)

const

Returns the node at the specified position. If no node exists at this position, an error will occur. Therefor it's absolutely necessary to check with hasNode(int position) before calling this method.

Parameters:

position

position (x-value) of the node that should be returned

Returns:

the node at the specified position

int VolVis::VolumeRendering::TransferFunction::getResolution

(

)

const

Returns the resolution of the transfer function.

Returns:

resolution of the transfer function texture

GLuint VolVis::VolumeRendering::TransferFunction::getTexture

(

)

const

Returns the id of the texture containing the transfer function

Returns:

openGL texture id

bool VolVis::VolumeRendering::TransferFunction::hasNode

(

int

position

)

const

Check if a node exists at the specified position

Parameters:

position

(x-value) where a node should be searched for

Returns:

false if no node exists

void VolVis::VolumeRendering::TransferFunction::openFile

(

std::string &

filePath

)

Opens a transfer function from a file. The file contains all nodes of the new transfer function.

Parameters:

filePath

path to the file which should be loaded.

See also:

saveToFile

bool VolVis::VolumeRendering::TransferFunction::removeNode

(

int

position

)

Removes the node which is stored at the specified position. The first and the last point cannot be removed.

Parameters:

position

position (x-value) of the node which should be removed

Returns:

false if position is less than 1 or greater than 4094

void VolVis::VolumeRendering::TransferFunction::saveToFile

(

std::string &

filePath

)

Saves this transfer function to a file. All nodes of this transfer function are written to a file.

Parameters:

filePath

path to the file where the transfer function should be saved

See also:

openFile

void VolVis::VolumeRendering::TransferFunction::setNode	(	int	position,
		Eigen::Vector3f &	color,
		float	alpha
	)

Convenience method. Does the same as void setNode(int position, TFNode* node)

Parameters:

	position	position (x-value) of the node
	color	3d-vector defining the color of the new node. The color components are defined as floats between 0 (black) and 1 (white)
	alpha	alpha value (y-value) of the new node

void VolVis::VolumeRendering::TransferFunction::setNode	(	int	position,
		TFNode &	node
	)

Sets a node at the specified position. If the node already exists, its values are changed, otherwise it is created.

Parameters:

	position	position (x-value) of the node
	node	the new node which is stored at the specified position

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

• TransferFunction.h

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