class QSGRendererInterface#

An interface providing access to some of the graphics API specific internals of the scenegraph. More…

Synopsis#

Virtual methods#

def getResource()
def graphicsApi()
def shaderCompilationType()
def shaderSourceType()
def shaderType()

Static functions#

def isApiRhiBased()

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#

Renderer interfaces allow accessing graphics API specific functionality in the scenegraph. Such internals are not typically exposed. However, when integrating custom rendering via QSGRenderNode for example, it may become necessary to query certain values, for instance the graphics device (e.g. the Direct3D or Vulkan device) that is used by the scenegraph.

QSGRendererInterface ‘s functions have varying availability. API and language queries, such as, graphicsApi() or shaderType() are always available, meaning it is sufficient to construct a QQuickWindow or QQuickView , and the graphics API or shading language in use can be queried right after via rendererInterface() . This guarantees that utilities like the GraphicsInfo QML type are able to report the correct values as early as possible, without having conditional property values - depending on for instance shaderType() - evaluate to unexpected values.

Engine-specific accessors, like getResource() , are however available only after the scenegraph is initialized. Additionally, there may be backend-specific limitations on when such functions can be called. The only way that is guaranteed to succeed is calling them when the rendering of a node (i.e. the preparation of the command list for the next frame) is active. In practice this typically means render() .

class GraphicsApi#

Constant	Description
QSGRendererInterface.Unknown	An unknown graphics API is in use
QSGRendererInterface.Software	The Qt Quick 2D Renderer is in use
QSGRendererInterface.OpenVG	OpenVG via EGL
QSGRendererInterface.OpenGL	OpenGL ES 2.0 or higher via a graphics abstraction layer.
QSGRendererInterface.Direct3D11	Direct3D 11 via a graphics abstraction layer.
QSGRendererInterface.Direct3D12	Direct3D 12 via a graphics abstraction layer.
QSGRendererInterface.Vulkan	Vulkan 1.0 via a graphics abstraction layer.
QSGRendererInterface.Metal	Metal via a graphics abstraction layer.
QSGRendererInterface.Null	Null (no output) via a graphics abstraction layer.

class Resource#

Constant	Description
QSGRendererInterface.DeviceResource	The resource is a pointer to the graphics device, when applicable. For example, a `VkDevice `, `MTLDevice ` or `ID3D11Device `. Note that with Vulkan the returned value is a pointer to the VkDevice, not the handle itself. This is because Vulkan handles may not be pointers, and may use a different size from the architecture’s pointer size so merely casting to/from `void ` is wrong.
QSGRendererInterface.CommandQueueResource	The resource is a pointer to the graphics command queue used by the scenegraph, when applicable. For example, a `VkQueue ` or `MTLCommandQueue `. Note that with Vulkan the returned value is a pointer to the VkQueue, not the handle itself.
QSGRendererInterface.CommandListResource	The resource is a pointer to the command list or buffer used by the scenegraph, when applicable. For example, a `VkCommandBuffer ` or `MTLCommandBuffer `. This object has limited validity, and is only valid while the scene graph is preparing the next frame. Note that with Vulkan the returned value is a pointer to the VkCommandBuffer, not the handle itself.
QSGRendererInterface.PainterResource	The resource is a pointer to the active QPainter used by the scenegraph, when running with the software backend.
QSGRendererInterface.RhiResource	The resource is a pointer to the QRhi instance used by the scenegraph, when applicable.
QSGRendererInterface.RhiSwapchainResource	The resource is a pointer to a QRhiSwapchain instance that is associated with the window. The value is null when the window is used in combination with `QQuickRenderControl` .
QSGRendererInterface.RhiRedirectCommandBuffer	The resource is a pointer to a QRhiCommandBuffer instance that is associated with the window and its `QQuickRenderControl` . The value is null when the window is not associated with a `QQuickRenderControl` .
QSGRendererInterface.RhiRedirectRenderTarget	The resource is a pointer to a QRhiTextureRenderTarget instance that is associated with the window and its `QQuickRenderControl` . The value is null when the window is not associated with a `QQuickRenderControl` . Note that the value always reflects the main texture render target and it does not depend on the Qt Quick scene, meaning it does not take any additional texture-targeting render passes generated by ShaderEffect or `QQuickItem` layers into account.
QSGRendererInterface.PhysicalDeviceResource	The resource is a pointer to the pysical device object used by the scenegraph, when applicable. For example, a `VkPhysicalDevice *`. Note that with Vulkan the returned value is a pointer to the VkPhysicalDevice, not the handle itself.
QSGRendererInterface.OpenGLContextResource	The resource is a pointer to the QOpenGLContext used by the scenegraph (on the render thread), when applicable.
QSGRendererInterface.DeviceContextResource	The resource is a pointer to the device context used by the scenegraph, when applicable. For example, a `ID3D11DeviceContext *`.
QSGRendererInterface.CommandEncoderResource	The resource is a pointer to the currently active render command encoder object used by the scenegraph, when applicable. For example, a `MTLRenderCommandEncoder *`. This object has limited validity, and is only valid while the scene graph is recording a render pass for the next frame.
QSGRendererInterface.VulkanInstanceResource	The resource is a pointer to the QVulkanInstance used by the scenegraph, when applicable.
QSGRendererInterface.RenderPassResource	The resource is a pointer to the main render pass used by the scenegraph, describing the color and depth/stecil attachments and how they are used. For example, a `VkRenderPass *`. Note that the value always reflects the main render target (either the on-screen window or the texture `QQuickRenderControl` redirects to) and it does not depend on the Qt Quick scene, meaning it does not take any additional texture-targeting render passes generated by ShaderEffect or `QQuickItem` layers into account.
QSGRendererInterface.RedirectPaintDevice	The resource is a pointer to QPaintDevice instance that is associated with the window and its `QQuickRenderControl` . The value is null when the window is not associated with a `QQuickRenderControl` .
QSGRendererInterface.GraphicsQueueFamilyIndexResource	The resource is a pointer to the graphics queue family index used by the scenegraph, when applicable. With Vulkan, this is a pointer to a `uint32_t` index value.
QSGRendererInterface.GraphicsQueueIndexResource	The resource is a pointer to the graphics queue index (uint32_t) used by the scenegraph, when applicable. With Vulkan, this is a pointer to a `uint32_t` index value, which in practice is the index of the VkQueue reported for `CommandQueueResource`.

class ShaderType#

Constant	Description
QSGRendererInterface.UnknownShadingLanguage	Not yet known due to no window and scenegraph associated
QSGRendererInterface.GLSL	GLSL or GLSL ES
QSGRendererInterface.HLSL	HLSL
QSGRendererInterface.RhiShader	Consumes QShader instances containing shader variants for multiple target languages and intermediate formats.

class ShaderCompilationType#

Constant	Description
QSGRendererInterface.RuntimeCompilation	(inherits `enum.Flag`) Runtime compilation of shader source code is supported
QSGRendererInterface.OfflineCompilation	Pre-compiled bytecode supported

class ShaderSourceType#

Constant	Description
QSGRendererInterface.ShaderSourceString	(inherits `enum.Flag`) Shader source can be provided as a string in the corresponding properties of ShaderEffect
QSGRendererInterface.ShaderSourceFile	Local or resource files containing shader source code are supported
QSGRendererInterface.ShaderByteCode	Local or resource files containing shader bytecode are supported

class RenderMode#

Constant	Description
QSGRendererInterface.RenderMode2D	Normal 2D rendering
QSGRendererInterface.RenderMode2DNoDepthBuffer	Normal 2D rendering with depth buffer disabled
QSGRendererInterface.RenderMode3D	Scene is rendered as part of a 3D graph

getResource(window, resource)#

Parameters:

window – QQuickWindow
resource – Resource

Return type:

void

Queries a graphics resource in window. Returns null when the resource in question is not supported or not available.

When successful, the returned pointer is either a direct pointer to an interface, or a pointer to an opaque handle that needs to be dereferenced first (for example, VkDevice dev = *static_cast<VkDevice *>(result)). The latter is necessary since such handles may have sizes different from a pointer.

Note

The ownership of the returned pointer is never transferred to the caller.

Note

This function must only be called on the render thread.

getResource(window, resource)

Parameters:

window – QQuickWindow
resource – str

Return type:

void

Queries a graphics resource. resource is a backend-specific key. This allows supporting any future resources that are not listed in the Resource enum.

Note

The ownership of the returned pointer is never transferred to the caller.

Note

This function must only be called on the render thread.

abstract graphicsApi()#

Return type:: GraphicsApi

Returns the graphics API that is in use by the Qt Quick scenegraph.

Note

This function can be called on any thread.

static isApiRhiBased(api)#

Parameters:: api – GraphicsApi
Return type:: bool

Returns true if api is based on a graphics abstraction layer (QRhi) instead of directly calling the native graphics API.

Note

This function can be called on any thread.

abstract shaderCompilationType()#

Return type:: Combination of ShaderCompilationType

Returns a bitmask of the shader compilation approaches supported by the Qt Quick backend the application is using.

Note

This function can be called on any thread.