Implements basic Bresenham algorithm for rasterization. More...

#include <WBresenham.h>

Inheritance diagram for WBresenham:

Collaboration diagram for WBresenham:

Public Member Functions
	WBresenham (std::shared_ptr< WGridRegular3D > grid, bool antialiased=true)
	Initializes new raster algo. More...

virtual	~WBresenham ()
	Finishes this raster algo. More...

virtual void	raster (const WLine &line)
	Rasterize the given line into the grid of dataset. More...

Public Member Functions inherited from WRasterAlgorithm
	WRasterAlgorithm (std::shared_ptr< WGridRegular3D > grid)
	Creates new raster algorithm within the given grid. More...

virtual	~WRasterAlgorithm ()
	Dispose a this raster algorithm. More...

std::shared_ptr< WDataSetScalar >	generateDataSet () const
	Computes a dataset out of our voxel values and the previously given grid. More...

void	addParameterizationAlgorithm (std::shared_ptr< WRasterParameterization > algorithm)
	This method allows the user of the raster algorithm to add arbitrary parameterizations. More...

virtual void	finished ()
	Called whenever all lines have been rasterized. More...

Protected Member Functions
virtual void	rasterSegment (const WPosition &start, const WPosition &end)
	Scans a line segment for voxels which are hit. More...

virtual void	markVoxel (const WVector3i &voxel, const int axis, const WPosition &start, const WPosition &end)
	Marks the given voxel as a hit. More...

virtual double	filter (const double distance) const
	Returns the value to mark the hit voxels with, depending on their distance to the line. More...

std::vector< double >	computeDistances (const size_t voxelNum, const WPosition &start, const WPosition &end) const
	Computes the distances for a voxel to the real line segment and also for its supporting voxels. More...

double	composeValue (double newValue, double existingValue) const
	Compose the new value for a voxel out of a new computed value and the already existing marking. More...

Protected Member Functions inherited from WRasterAlgorithm
virtual void	parameterizeVoxel (const WVector3i &voxel, size_t voxelIdx, const int axis, const double value, const WPosition &start, const WPosition &end)
	This method allows all registered parameterization algorithms to update. More...

virtual void	newLine (const WLine &line)
	Distribute a new line getting rasterized to all parameterize algorithms. More...

virtual void	newSegment (const WPosition &start, const WPosition &end)
	Distribute a new segment of a line to all parameterization algorithms. More...

Protected Attributes
bool	m_antialiased
	If true also some supporting voxels are marked. More...

Protected Attributes inherited from WRasterAlgorithm
std::vector< std::shared_ptr< WRasterParameterization > >	m_parameterizations
	All the parameterization algorithms to apply while rasterizing a line. More...

std::shared_mutex	m_parameterizationsLock
	The mutex used to lock access to m_parameterizations. More...

std::shared_ptr< WGridRegular3D >	m_grid
	The grid is used for the following purposes: More...

std::vector< double >	m_values
	Stores the value of each voxel. More...

Friends
class	WBresenhamTest
	Only UnitTests may be friends. More...

Detailed Description

Implements basic Bresenham algorithm for rasterization.

Definition at line 42 of file WBresenham.h.

Constructor & Destructor Documentation

◆ WBresenham()

WBresenham::WBresenham	(	std::shared_ptr< WGridRegular3D >	grid,
		bool	antialiased = `true`
	)

Initializes new raster algo.

Parameters

grid	The grid which defines the voxels which should be marked.
antialiased	If true then all voxels of a line are supported with anti-aliasing voxels around

Definition at line 40 of file WBresenham.cpp.

◆ ~WBresenham()

WBresenham::~WBresenham ( )

virtual

Finishes this raster algo.

Definition at line 46 of file WBresenham.cpp.

Member Function Documentation

◆ composeValue()

double WBresenham::composeValue	(	double	newValue,
		double	existingValue
	)		const

protected

Compose the new value for a voxel out of a new computed value and the already existing marking.

Parameters

newValue	Newly computed value
existingValue	The mark already existing for the voxel (aka previous mark or markSoFar)

Returns: The new mark for that voxel

Definition at line 189 of file WBresenham.cpp.

Referenced by markVoxel().

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◆ computeDistances()

std::vector< double > WBresenham::computeDistances	(	const size_t	voxelNum,
		const WPosition &	start,
		const WPosition &	end
	)		const

protected

Computes the distances for a voxel to the real line segment and also for its supporting voxels.

Parameters

voxelNum	The voxel number
start	Start point of the line segment
end	End point of the line segment

Returns: A vector of distances where first distance is the distance of the voxel itself, then x+1, x-1 supporting voxel, then y+1 and y-1 and at last z+1 and z-1.

Definition at line 160 of file WBresenham.cpp.

References WRasterAlgorithm::m_grid.

Referenced by markVoxel().

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◆ filter()

double WBresenham::filter ( const double distance ) const

protectedvirtual

Returns the value to mark the hit voxels with, depending on their distance to the line.

Parameters

distance Distance of the voxel to the line.

Returns: Value which is used for marking a voxel.

Definition at line 281 of file WBresenham.cpp.

Referenced by markVoxel().

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◆ markVoxel()

void WBresenham::markVoxel	(	const WVector3i &	voxel,
		const int	axis,
		const WPosition &	start,
		const WPosition &	end
	)

protectedvirtual

Marks the given voxel as a hit.

If anti-aliasing is enabled also some supporting voxels nearby are marked. The value for marking the voxel depends on the distance from its center point to the real line.

Parameters

voxel	The voxel to mark
axis	Along which axis the traversal takes place. Since when walking in e.g. X-direction there are not supporting voxels in the same direction.
start	Start point of the line segment (used to computed the distance)
end	End point of the line segment (used to computed the distance)

Definition at line 195 of file WBresenham.cpp.

References composeValue(), computeDistances(), filter(), m_antialiased, WRasterAlgorithm::m_grid, WRasterAlgorithm::m_values, and WRasterAlgorithm::parameterizeVoxel().

Referenced by rasterSegment(), and WBresenhamDBL::rasterSegment().

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◆ raster()

void WBresenham::raster ( const WLine & line )

virtual

Rasterize the given line into the grid of dataset.

The value of the voxel which will be hit changes its value.

Parameters

line	Polyline which is about to be rastered.

Implements WRasterAlgorithm.

Definition at line 50 of file WBresenham.cpp.

References wlog::debug(), WRasterAlgorithm::m_parameterizationsLock, WRasterAlgorithm::newLine(), WRasterAlgorithm::newSegment(), rasterSegment(), and WMixinVector< ValueT >::size().

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◆ rasterSegment()

void WBresenham::rasterSegment	(	const WPosition &	start,
		const WPosition &	end
	)

protectedvirtual

Scans a line segment for voxels which are hit.

Warning: Not every voxel which is hit by the segment will be marked but at least so many voxels so that the segment is represented by those voxels.; Every line starting in voxel A and ending in voxel B is rastered the same way as the line from the middlepoint of A to the middlepoint of B.

Note: This algorithm is fast since using only integer operations. This is the real Bresenham

Parameters

start	Start point of the line segment
end	End point of the line segment

Reimplemented in WBresenhamDBL.

Definition at line 70 of file WBresenham.cpp.

References WRasterAlgorithm::m_grid, and markVoxel().

Referenced by raster().

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Friends And Related Function Documentation

◆ WBresenhamTest

friend class WBresenhamTest

friend

Only UnitTests may be friends.

Definition at line 47 of file WBresenham.h.

Member Data Documentation

◆ m_antialiased

bool WBresenham::m_antialiased

protected

If true also some supporting voxels are marked.

Definition at line 140 of file WBresenham.h.

Referenced by markVoxel().

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

Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ WBresenham()

◆ ~WBresenham()

Member Function Documentation

◆ composeValue()

◆ computeDistances()

◆ filter()

◆ markVoxel()

◆ raster()

◆ rasterSegment()

Friends And Related Function Documentation

◆ WBresenhamTest

Member Data Documentation

◆ m_antialiased