QSGTexture

The QSGTexture class is a baseclass for textures used in the scene graph. More…

Inherited by: QSGDynamicTexture

Synopsis

Functions

• def anisotropyLevel ()

• def comparisonKey ()

• def convertToNormalizedSourceRect (rect)

• def filtering ()

• def horizontalWrapMode ()

• def mipmapFiltering ()

• def setAnisotropyLevel (level)

• def setFiltering (filter)

• def setHorizontalWrapMode (hwrap)

• def setMipmapFiltering (filter)

• def setVerticalWrapMode (vwrap)

• def updateBindOptions ([force=false])

• def verticalWrapMode ()

Virtual functions

• def bind ()

• def hasAlphaChannel ()

• def hasMipmaps ()

• def isAtlasTexture ()

• def normalizedTextureSubRect ()

• def removedFromAtlas ()

• def textureId ()

• def textureSize ()

Detailed Description

Users can freely implement their own texture classes to support arbitrary input textures, such as YUV video frames or 8 bit alpha masks. The scene graph backend provides a default implementation of normal color textures. As the implementation of these may be hardware specific, they are constructed via the factory function createTextureFromImage() .

The texture is a wrapper around an OpenGL texture, which texture id is given by textureId() and which size in pixels is given by textureSize() . hasAlphaChannel() reports if the texture contains opacity values and hasMipmaps() reports if the texture contains mipmap levels.

To use a texture, call the bind() function. The texture parameters specifying how the texture is bound, can be specified with setMipmapFiltering() , setFiltering() , setHorizontalWrapMode() and setVerticalWrapMode() . The texture will internally try to store these values to minimize the OpenGL state changes when the texture is bound.

Texture Atlasses

Some scene graph backends use texture atlasses, grouping multiple small textures into one large texture. If this is the case, the function isAtlasTexture() will return true. Atlasses are used to aid the rendering algorithm to do better sorting which increases performance. The location of the texture inside the atlas is given with the normalizedTextureSubRect() function.

If the texture is used in such a way that atlas is not preferable, the function removedFromAtlas() can be used to extract a non-atlassed copy.

Note

All classes with QSG prefix should be used solely on the scene graph’s rendering thread. See Scene Graph and Rendering for more information.

See also

Scene Graph - Rendering FBOs Scene Graph - Rendering FBOs in a thread

class PySide2.QtQuick.QSGTexture

Constructs the QSGTexture base class.

PySide2.QtQuick.QSGTexture.WrapMode

Specifies how the texture should treat texture coordinates.

Constant	Description
QSGTexture.Repeat	Only the fractional part of the texture coordinate is used, causing values above 1 and below 0 to repeat.
QSGTexture.ClampToEdge	Values above 1 are clamped to 1 and values below 0 are clamped to 0.
QSGTexture.MirroredRepeat	When the texture coordinate is even, only the fractional part is used. When odd, the texture coordinate is set to 1 - fractional part. This value has been introduced in Qt 5.10.

PySide2.QtQuick.QSGTexture.Filtering

Specifies how sampling of texels should filter when texture coordinates are not pixel aligned.

Constant	Description
QSGTexture.None	No filtering should occur. This value is only used together with setMipmapFiltering() .
QSGTexture.Nearest	Sampling returns the nearest texel.
QSGTexture.Linear	Sampling returns a linear interpolation of the neighboring texels.

PySide2.QtQuick.QSGTexture.AnisotropyLevel

Specifies the anisotropic filtering level to be used when the texture is not screen aligned.

Constant	Description
QSGTexture.AnisotropyNone	No anisotropic filtering.
QSGTexture.Anisotropy2x	2x anisotropic filtering.
QSGTexture.Anisotropy4x	4x anisotropic filtering.
QSGTexture.Anisotropy8x	8x anisotropic filtering.
QSGTexture.Anisotropy16x	16x anisotropic filtering.

New in version 5.9.

PySide2.QtQuick.QSGTexture.anisotropyLevel()

Return type:

AnisotropyLevel

Returns the anisotropy level in use for filtering this texture.

See also

setAnisotropyLevel()

PySide2.QtQuick.QSGTexture.bind()

Call this function to bind this texture to the current texture target.

Binding a texture may also include uploading the texture data from a previously set QImage .

Warning

This function should only be called when running with the direct OpenGL rendering path.

Warning

This function can only be called from the rendering thread.

PySide2.QtQuick.QSGTexture.comparisonKey()

Return type:

int

Returns a key suitable for comparing textures. Typically used in compare() implementations.

Just comparing QSGTexture pointers is not always sufficient because two QSGTexture instances that refer to the same native texture object underneath should also be considered equal. Hence this function.

Note

Unlike textureId() , implementations of this function are not expected to and should not create any graphics resources (so texture objects) in case there is none yet.

A QSGTexture that does not have a native texture object underneath is typically not equal to any other QSGTexture . There are exceptions to this, in particular when atlasing is used (where multiple textures share the same atlas texture under the hood), that is then up to the subclass implementations to deal with as appropriate.

Warning

This function can only be called from the rendering thread.

PySide2.QtQuick.QSGTexture.convertToNormalizedSourceRect(rect)

Parameters:

rect – PySide2.QtCore.QRectF

Return type:

PySide2.QtCore.QRectF

Returns rect converted to normalized coordinates.

See also

normalizedTextureSubRect()

PySide2.QtQuick.QSGTexture.filtering()

Return type:

Filtering

Returns the sampling mode to be used for this texture.

See also

setFiltering()

PySide2.QtQuick.QSGTexture.hasAlphaChannel()

Return type:

bool

Returns true if the texture data contains an alpha channel.

PySide2.QtQuick.QSGTexture.hasMipmaps()

Return type:

bool

Returns true if the texture data contains mipmap levels.

PySide2.QtQuick.QSGTexture.horizontalWrapMode()

Return type:

WrapMode

Returns the horizontal wrap mode to be used for this texture.

See also

setHorizontalWrapMode()

PySide2.QtQuick.QSGTexture.isAtlasTexture()

Return type:

bool

Returns weither this texture is part of an atlas or not.

The default implementation returns false.

PySide2.QtQuick.QSGTexture.mipmapFiltering()

Return type:

Filtering

Returns whether mipmapping should be used when sampling from this texture.

See also

setMipmapFiltering()

PySide2.QtQuick.QSGTexture.normalizedTextureSubRect()

Return type:

PySide2.QtCore.QRectF

Returns the rectangle inside textureSize() that this texture represents in normalized coordinates.

The default implementation returns a rect at position (0, 0) with width and height of 1.

PySide2.QtQuick.QSGTexture.removedFromAtlas()

Return type:

PySide2.QtQuick.QSGTexture

This function returns a copy of the current texture which is removed from its atlas.

The current texture remains unchanged, so texture coordinates do not need to be updated.

Removing a texture from an atlas is primarily useful when passing it to a shader that operates on the texture coordinates 0-1 instead of the texture subrect inside the atlas.

If the texture is not part of a texture atlas, this function returns 0.

Implementations of this function are recommended to return the same instance for multiple calls to limit memory usage.

Warning

This function can only be called from the rendering thread.

PySide2.QtQuick.QSGTexture.setAnisotropyLevel(level)

Parameters:

level – AnisotropyLevel

Sets the level of anisotropic filtering to be used for the upcoming bind() call to level . The default value is AnisotropyNone , which means no anisotropic filtering is enabled.

See also

anisotropyLevel()

PySide2.QtQuick.QSGTexture.setFiltering(filter)

Parameters:

filter – Filtering

Sets the sampling mode to be used for the upcoming bind() call to filter .

See also

filtering()

PySide2.QtQuick.QSGTexture.setHorizontalWrapMode(hwrap)

Parameters:

hwrap – WrapMode

Sets the horizontal wrap mode to be used for the upcoming bind() call to hwrap

See also

horizontalWrapMode()

PySide2.QtQuick.QSGTexture.setMipmapFiltering(filter)

Parameters:

filter – Filtering

Sets the mipmap sampling mode to be used for the upcoming bind() call to filter .

Setting the mipmap filtering has no effect it the texture does not have mipmaps.

See also

mipmapFiltering() hasMipmaps()

PySide2.QtQuick.QSGTexture.setVerticalWrapMode(vwrap)

Parameters:

vwrap – WrapMode

Sets the vertical wrap mode to be used for the upcoming bind() call to vwrap

See also

verticalWrapMode()

PySide2.QtQuick.QSGTexture.textureId()

Return type:

int

Returns the OpenGL texture id for this texture.

The default value is 0, indicating that it is an invalid texture id.

The function should at all times return the correct texture id.

Warning

This function can only be called from the rendering thread.

PySide2.QtQuick.QSGTexture.textureSize()

Return type:

PySide2.QtCore.QSize

Returns the size of the texture.

PySide2.QtQuick.QSGTexture.updateBindOptions([force=false])

Parameters:

force – bool

Update the texture state to match the filtering, mipmap and wrap options currently set.

If force is true, all properties will be updated regardless of weither they have changed or not.

PySide2.QtQuick.QSGTexture.verticalWrapMode()

Return type:

WrapMode

Returns the vertical wrap mode to be used for this texture.

See also

setVerticalWrapMode()