Class: QgsTessellator

Tessellates 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.

Methods

addPolygon	Tessellates a triangle and adds its vertex entries to the output data array
data	Returns array of triangle vertex data
dataVerticesCount	Returns the number of vertices stored in the output data array
error	Returns a descriptive error string if the tessellation failed.
isOutputZUp	Returns whether the "up" direction should be the Z axis on output (True), otherwise the "up" direction will be the Y axis (False).
setOutputZUp	Sets whether the "up" direction should be the Z axis on output (True), otherwise the "up" direction will be the Y axis (False).
stride	Returns size of one vertex entry in bytes
zMaximum	Returns maximal Z value of the data (in world coordinates)
zMinimum	Returns minimal Z value of the data (in world coordinates)

class qgis.core.QgsTessellator

Bases: object

__init__(originX: float, originY: float, addNormals: bool, invertNormals: bool = False, addBackFaces: bool = False, noZ: bool = False, addTextureCoords: bool = False, facade: int = 3, textureRotation: float = 0)

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

Parameters:

• originX (float)

• originY (float)

• addNormals (bool)

• invertNormals (bool = False)

• addBackFaces (bool = False)

• noZ (bool = False)

• addTextureCoords (bool = False)

• facade (int = 3)

• textureRotation (float = 0)

__init__(bounds: QgsRectangle, addNormals: bool, invertNormals: bool = False, addBackFaces: bool = False, noZ: bool = False, addTextureCoords: bool = False, facade: int = 3, textureRotation: float = 0)

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.

Added in version 3.10.

Parameters:

• bounds (QgsRectangle)

• addNormals (bool)

• invertNormals (bool = False)

• addBackFaces (bool = False)

• noZ (bool = False)

• addTextureCoords (bool = False)

• facade (int = 3)

• textureRotation (float = 0)

__init__(a0: QgsTessellator)

Parameters:

a0 (QgsTessellator)

addPolygon(self, polygon: QgsPolygon, extrusionHeight: float)

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

Parameters:

• polygon (QgsPolygon)

• extrusionHeight (float)

data(self) → List[float]

Returns array of triangle vertex data

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

Return type:

List[float]

dataVerticesCount(self) → int

Returns the number of vertices stored in the output data array

Return type:

int

error(self) → str

Returns a descriptive error string if the tessellation failed.

Added in version 3.34.

Return type:

str

isOutputZUp(self) → bool

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).

Added in version 3.42.

Return type:

bool

setOutputZUp(self, zUp: bool)

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).

Added in version 3.42.

Parameters:

zUp (bool)

stride(self) → int

Returns size of one vertex entry in bytes

Return type:

int

zMaximum(self) → float

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

Added in version 3.12.

Return type:

float

zMinimum(self) → float

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

Added in version 3.12.

Return type:

float