class QQuickRenderTarget

The QQuickRenderTarget class provides an opaque container for native graphics resources specifying a render target, and associated metadata. More…

Synopsis

Methods

Static functions

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description

class Flag

(inherits enum.Flag) Flags for the static QQuickRenderTarget constructor functions.

Constant

Description

QQuickRenderTarget.Flag.MultisampleResolve

Indicates that the sampleCount argument is not the number of samples for the provided texture (and that the texture is still a non-multisample texture), but rather the desired samples for multisample antialiasing. Triggers automatically creating and managing an intermediate multisample texture (or texture array) as the color buffer, transparently to the application. The samples are resolved into the provided texture at the end of the render pass automatically. When this flag is not set, and the sampleCount argument is greater than 1, it implies the provided texture is multisample. The flag has no effect is the sampleCount is 1 (indicating that multisampling is not involved).

Added in version 6.8.

__init__()

Constructs a default QQuickRenderTarget that does not reference any native objects.

__init__(other)
Parameters:

other – QQuickRenderTarget

depthTexture()
Return type:

QRhiTexture

Returns the currently set depth texture or, in most cases, None.

The value is only non-null when setDepthTexture() was called.

devicePixelRatio()
Return type:

float

Returns the device pixel ratio for the render target. This is the ratio between device pixels and device independent pixels.

The default device pixel ratio is 1.0.

static fromOpenGLRenderBuffer(renderbufferId, pixelSize[, sampleCount=1])
Parameters:

  • renderbufferId – int

  • pixelSize – QSize

  • sampleCount – int

Return type:

QQuickRenderTarget

Returns a new QQuickRenderTarget referencing an OpenGL renderbuffer object specified by renderbufferId.

The renderbuffer will be used as the color attachment for the internal framebuffer object. This function is provided to allow targeting renderbuffers that are created by the application with some external buffer underneath, such as an EGLImageKHR. Once the application has called glEGLImageTargetRenderbufferStorageOES , the renderbuffer can be passed to this function.

pixelSize specifies the size of the image, in pixels.

sampleCount specifies the number of samples. 0 or 1 means no multisampling, while a value like 4 or 8 states that the native object is a multisample renderbuffer.

Note

the resulting QQuickRenderTarget does not own any native resources, it merely contains references and the associated metadata of the size and sample count. It is the caller’s responsibility to ensure that the native resource exists as long as necessary.

See also

setRenderTarget() QQuickRenderControl

static fromOpenGLTexture(textureId, pixelSize[, sampleCount=1])
Parameters:

  • textureId – int

  • pixelSize – QSize

  • sampleCount – int

Return type:

QQuickRenderTarget

This is an overloaded function.

Returns a new QQuickRenderTarget referencing an OpenGL texture object specified by textureId. The texture is assumed to have a format of GL_RGBA (GL_RGBA8).

pixelSize specifies the size of the image, in pixels. Currently only 2D textures are supported.

sampleCount specifies the number of samples. 0 or 1 means no multisampling, while a value like 4 or 8 states that the native object is a multisample texture.

The texture is used as the first color attachment of the render target used by the Qt Quick scenegraph. A depth-stencil buffer, if applicable, is created and used automatically.

The OpenGL object name textureId must be a valid name in the rendering context used by the Qt Quick scenegraph.

Note

the resulting QQuickRenderTarget does not own any native resources, it merely contains references and the associated metadata of the size and sample count. It is the caller’s responsibility to ensure that the native resource exists as long as necessary.

See also

setRenderTarget() QQuickRenderControl

static fromOpenGLTexture(textureId, format, pixelSize[, sampleCount=1])
Parameters:

  • textureId – int

  • format – int

  • pixelSize – QSize

  • sampleCount – int

Return type:

QQuickRenderTarget

Returns a new QQuickRenderTarget referencing an OpenGL texture object specified by textureId.

format specifies the native internal format of the texture. Only texture formats that are supported by Qt’s rendering infrastructure should be used.

pixelSize specifies the size of the image, in pixels. Currently only 2D textures are supported.

sampleCount specifies the number of samples. 0 or 1 means no multisampling, while a value like 4 or 8 states that the native object is a multisample texture.

The texture is used as the first color attachment of the render target used by the Qt Quick scenegraph. A depth-stencil buffer, if applicable, is created and used automatically.

The OpenGL object name textureId must be a valid name in the rendering context used by the Qt Quick scenegraph.

Note

the resulting QQuickRenderTarget does not own any native resources, it merely contains references and the associated metadata of the size and sample count. It is the caller’s responsibility to ensure that the native resource exists as long as necessary.

See also

setRenderTarget() QQuickRenderControl

static fromOpenGLTexture(textureId, format, pixelSize, sampleCount, arraySize, flags)
Parameters:

  • textureId – int

  • format – int

  • pixelSize – QSize

  • sampleCount – int

  • arraySize – int

  • flags – Combination of Flag

Return type:

QQuickRenderTarget

This is an overloaded function.

Returns a new QQuickRenderTarget referencing an OpenGL 2D texture or texture array object specified by textureId.

format specifies the native internal format of the texture. Only texture formats that are supported by Qt’s rendering infrastructure should be used.

pixelSize specifies the size of the image, in pixels. Currently only 2D textures and 2D texture arrays are supported.

sampleCount specifies the number of samples. 0 or 1 means no multisampling, while a value like 4 or 8 states that the native object is a multisample texture, except when flags contains MultisampleResolve . In that case, textureId is assumed to be a non-multisample 2D texture or 2D texture array, and sampleCount defines the number of samples desired. The resulting QQuickRenderTarget will use an intermediate, automatically created multisample texture (or texture array) as its color attachment, and will resolve the samples into textureId. This is the recommended approach to perform MSAA when the native OpenGL texture is not already multisample.

When arraySize is greater than 1, it implies multiview rendering ( GL_OVR_multiview , QRhiColorAttachment::setMultiViewCount()), which can be relevant with VR/AR especially. In this case arraySize is the number of views, typically 2. See viewCount() for details on enabling multiview rendering within the Qt Quick scenegraph.

A depth-stencil buffer, if applicable, is created and used automatically. When the color buffer is multisample, the depth-stencil buffer will automatically be multisample too. For multiview rendering, the depth-stencil texture will automatically be made an array with a matching arraySize.

The OpenGL object name textureId must be a valid 2D texture name in the rendering context used by the Qt Quick scenegraph. When arraySize is greater than 1, textureId must be a valid 2D texture array name.

Note

the resulting QQuickRenderTarget does not own any native resources, it merely contains references and the associated metadata of the size and sample count. It is the caller’s responsibility to ensure that the native resource exists as long as necessary.

Note

The implementation of this overload is not compatible with OpenGL ES 2.0 or 3.0, and requires OpenGL ES 3.1 at minimum. (or OpenGL 3.0 on desktop)

See also

setRenderTarget() QQuickRenderControl fromOpenGLTexture()

static fromPaintDevice(device)
Parameters:

device – QPaintDevice

Return type:

QQuickRenderTarget

Returns a new QQuickRenderTarget referencing a paint device object specified by device.

This option of redirecting rendering to a QPaintDevice is available only when running with the software backend of Qt Quick.

Note

The QQuickRenderTarget does not take ownship of device, it is the caller’s responsibility to ensure the object exists as long as necessary.

See also

setRenderTarget() QQuickRenderControl

static fromRhiRenderTarget(renderTarget)
Parameters:

renderTarget – QRhiRenderTarget

Return type:

QQuickRenderTarget

Returns a new QQuickRenderTarget referencing an existing renderTarget.

renderTarget will in most cases be a QRhiTextureRenderTarget, which allows directing the Qt Quick scene’s rendering into a QRhiTexture.

Note

the resulting QQuickRenderTarget does not own renderTarget and any underlying native resources, it merely contains references and the associated metadata of the size and sample count. It is the caller’s responsibility to ensure that the referenced resources exists as long as necessary.

See also

setRenderTarget() QQuickRenderControl

isNull()
Return type:

bool

Returns true if this QQuickRenderTarget is default constructed, referencing no native objects.

mirrorVertically()
Return type:

bool

Returns Returns whether the render target is mirrored vertically.

The default value is false.

__ne__(rhs)
Parameters:

rhs – QQuickRenderTarget

Return type:

bool

Returns true if a and b refer to a different set of native objects, or the associated data (size, sample count) does not match.

__eq__(rhs)
Parameters:

rhs – QQuickRenderTarget

Return type:

bool

Returns true if a and b refer to the same set of native objects and have matching associated data (size, sample count).

setDepthTexture(texture)
Parameters:

texture – QRhiTexture

Requests using the given texture as the depth or depth-stencil buffer. Ownership of texture is not taken.

The request is only taken into account when relevant. For example, calling this function has no effect with fromRhiRenderTarget() , fromPaintDevice() , or fromOpenGLRenderBuffer() .

Normally a depth-stencil buffer is created automatically, transparently to the user of QQuickRenderTarget . Therefore, there is no need to call this function in most cases when working with QQuickRenderTarget . In special circumstances, it can however become essential to be able to provide a texture to render depth (or depth and stencil) data into, instead of letting Qt Quick create its own intermediate textures or buffers. An example of this is OpenXR and its extensions such as XR_KHR_composition_layer_depth . In order to “submit the depth buffer” to the XR compositor, one has to, in practice, retrieve an already created depth (depth-stencil) texture from OpenXR (from the XrSwapchain) and use that texture as the render target for depth data. That would not be possible without this function.

Note

The texture is always expected to be a non-multisample 2D texture or texture array (for multiview). If MSAA is involved, the samples are resolved into texture at the end of the render pass, regardless of having the MultisampleResolve flag set or not. MSAA is only supported for depth (depth-stencil) textures when the underlying 3D API supports this, and this support is not universally available. See the relevant QRhi feature flag for details. When this is not supported and multisampling is requested in combination with a custom depth texture, texture is not going to be touched during rendering and a warning is printed.

Note

When it comes to OpenGL and OpenGL ES, using depth textures is not functional on OpenGL ES 2.0 and requires at least OpenGL ES 3.0. Multisample (MSAA) support is not available without at least OpenGL ES 3.1, or OpenGL 3.0 on desktop.

See also

depthTexture()

setDevicePixelRatio(ratio)
Parameters:

ratio – float

Sets the device pixel ratio for this render target to ratio. This is the ratio between device pixels and device independent pixels.

Note that the specified device pixel ratio value will be ignored if renderWindow() is re-implemented to return a valid QWindow.

setMirrorVertically(enable)
Parameters:

enable – bool

Sets the size of the render target contents should be mirrored vertically to enable when drawing. This allows easy integration of third-party rendering code that does not follow the standard expectations.

Note

This function should not be used when using the software backend.

See also

mirrorVertically()