QgsTessellator Class Reference

Class that takes care of tessellation of polygons into triangles. More...

#include <qgstessellator.h>

Public Member Functions
	QgsTessellator (const QgsRectangle &bounds, bool addNormals, bool invertNormals=false, bool addBackFaces=false, bool noZ=false, bool addTextureCoords=false, int facade=3, float textureRotation=0.0f)
	Creates tessellator with a specified bounds of input geometry coordinates.
	QgsTessellator (double originX, double originY, bool addNormals, bool invertNormals=false, bool addBackFaces=false, bool noZ=false, bool addTextureCoords=false, int facade=3, float textureRotation=0.0f)
	Creates tessellator with a specified origin point of the world (in map coordinates)
void	addPolygon (const QgsPolygon &polygon, float extrusionHeight)
	Tessellates a triangle and adds its vertex entries to the output data array.
std::unique_ptr< QgsMultiPolygon >	asMultiPolygon () const
	Returns the triangulation as a multipolygon geometry.
QVector< float >	data () const
	Returns array of triangle vertex data.
int	dataVerticesCount () const
	Returns the number of vertices stored in the output data array.
QString	error () const
	Returns a descriptive error string if the tessellation failed.
bool	isOutputZUp () const
	Returns whether the "up" direction should be the Z axis on output (true), otherwise the "up" direction will be the Y axis (false).
void	setOutputZUp (bool zUp)
	Sets whether the "up" direction should be the Z axis on output (true), otherwise the "up" direction will be the Y axis (false).
int	stride () const
	Returns size of one vertex entry in bytes.
float	zMaximum () const
	Returns maximal Z value of the data (in world coordinates)
float	zMinimum () const
	Returns minimal Z value of the data (in world coordinates)

Detailed Description

Class that takes care of tessellation of polygons into triangles.

It is expected that client code will create the tessellator object, then repeatedly call addPolygon() method that will generate triangles, and finally call data() to get final vertex data.

Optionally provides extrusion by adding triangles that serve as walls when extrusion height is non-zero.

Definition at line 39 of file qgstessellator.h.

Constructor & Destructor Documentation

QgsTessellator() [1/2]

QgsTessellator::QgsTessellator	(	double	originX,
		double	originY,
		bool	addNormals,
		bool	invertNormals = false,
		bool	addBackFaces = false,
		bool	noZ = false,
		bool	addTextureCoords = false,
		int	facade = 3,
		float	textureRotation = 0.0f
	)

Creates tessellator with a specified origin point of the world (in map coordinates)

Definition at line 179 of file qgstessellator.cpp.

QgsTessellator() [2/2]

QgsTessellator::QgsTessellator	(	const QgsRectangle &	bounds,
		bool	addNormals,
		bool	invertNormals = false,
		bool	addBackFaces = false,
		bool	noZ = false,
		bool	addTextureCoords = false,
		int	facade = 3,
		float	textureRotation = 0.0f
	)

Creates tessellator with a specified bounds of input geometry coordinates.

This constructor allows the tessellator to map input coordinates to a desirable range for numerical stability during calculations.

If noZ is true, then a 2-dimensional tessellation only will be performed and all z coordinates will be ignored.

Since

QGIS 3.10

Definition at line 194 of file qgstessellator.cpp.

Member Function Documentation

addPolygon()

void QgsTessellator::addPolygon	(	const QgsPolygon &	polygon,
		float	extrusionHeight
	)

Tessellates a triangle and adds its vertex entries to the output data array.

Definition at line 484 of file qgstessellator.cpp.

asMultiPolygon()

std::unique_ptr< QgsMultiPolygon > QgsTessellator::asMultiPolygon

(

)

const

Returns the triangulation as a multipolygon geometry.

Definition at line 818 of file qgstessellator.cpp.

data()

QVector< float > QgsTessellator::data ( ) const

inline

Returns array of triangle vertex data.

Vertice coordinates are stored as (x, z, -y)

Definition at line 82 of file qgstessellator.h.

dataVerticesCount()

int QgsTessellator::dataVerticesCount

(

)

const

Returns the number of vertices stored in the output data array.

Definition at line 813 of file qgstessellator.cpp.

error()

QString QgsTessellator::error ( ) const

inline

Returns a descriptive error string if the tessellation failed.

Since

QGIS 3.34

Definition at line 112 of file qgstessellator.h.

isOutputZUp()

bool QgsTessellator::isOutputZUp ( ) const

inline

Returns whether the "up" direction should be the Z axis on output (true), otherwise the "up" direction will be the Y axis (false).

The default value is false (to keep compatibility for existing tessellator use cases).

Since

QGIS 3.42

Definition at line 72 of file qgstessellator.h.

setOutputZUp()

void QgsTessellator::setOutputZUp ( bool  zUp )

inline

Sets whether the "up" direction should be the Z axis on output (true), otherwise the "up" direction will be the Y axis (false).

The default value is false (to keep compatibility for existing tessellator use cases).

Since

QGIS 3.42

Definition at line 64 of file qgstessellator.h.

stride()

int QgsTessellator::stride ( ) const

inline

Returns size of one vertex entry in bytes.

Definition at line 88 of file qgstessellator.h.

zMaximum()

float QgsTessellator::zMaximum ( ) const

inline

Returns maximal Z value of the data (in world coordinates)

Since

QGIS 3.12

Definition at line 105 of file qgstessellator.h.

zMinimum()

float QgsTessellator::zMinimum ( ) const

inline

Returns minimal Z value of the data (in world coordinates)

Since

QGIS 3.12

Definition at line 99 of file qgstessellator.h.

---

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

• /build/qgis-3.41.0+git20241110+fda2aa46e9a+99sid/src/core/qgstessellator.h
• /build/qgis-3.41.0+git20241110+fda2aa46e9a+99sid/src/core/qgstessellator.cpp