- Qt 6.10
- Qt Quick
- C++ Classes
- QSGRendererInterface
- Qt 6.10.2 Reference Documentation

# QSGRendererInterface Class

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

Header: | `#include <QSGRendererInterface>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Quick)` `target_link_libraries(mytarget PRIVATE Qt6::Quick)`
qmake: | `QT += quick`

- List of all members, including inherited members

## Public Types

enum | GraphicsApi { Unknown, Software, OpenVG, OpenGL, Direct3D11, …, Null }
enum | RenderMode { RenderMode2D, RenderMode2DNoDepthBuffer, RenderMode3D }
enum | Resource { DeviceResource, CommandQueueResource, CommandListResource, PainterResource, RhiResource, …, GraphicsQueueIndexResource }
enum | ShaderCompilationType { RuntimeCompilation, OfflineCompilation }
flags | ShaderCompilationTypes
enum | ShaderSourceType { ShaderSourceString, ShaderSourceFile, ShaderByteCode }
flags | ShaderSourceTypes
enum | ShaderType { UnknownShadingLanguage, GLSL, HLSL, RhiShader }

## Public Functions

virtual void * | getResource(QQuickWindow *window, QSGRendererInterface::Resource resource) const
virtual void * | getResource(QQuickWindow *window, const char *resource) const
virtual QSGRendererInterface::GraphicsApi | graphicsApi() const = 0
virtual QSGRendererInterface::ShaderCompilationTypes | shaderCompilationType() const = 0
virtual QSGRendererInterface::ShaderSourceTypes | shaderSourceType() const = 0
virtual QSGRendererInterface::ShaderType | shaderType() const = 0

## Static Public Members

bool | isApiRhiBased(QSGRendererInterface::GraphicsApi api)

## 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 QQuickWindow::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 QSGRenderNode::render().

## Member Type Documentation

### enum QSGRendererInterface::GraphicsApi

Constant | Value | Description
--- | --- | ---
`QSGRendererInterface::Unknown` | `0` | An unknown graphics API is in use
`QSGRendererInterface::Software` | `1` | The Qt Quick 2D Renderer is in use
`QSGRendererInterface::OpenVG` | `2` | OpenVG via EGL
`QSGRendererInterface::OpenGL (since Qt 5.14)` | `3` | OpenGL ES 2.0 or higher via a graphics abstraction layer.
`QSGRendererInterface::Direct3D11 (since Qt 5.14)` | `4` | Direct3D 11 via a graphics abstraction layer.
`QSGRendererInterface::Direct3D12 (since Qt 6.6)` | `8` | Direct3D 12 via a graphics abstraction layer.
`QSGRendererInterface::Vulkan (since Qt 5.14)` | `5` | Vulkan 1.0 via a graphics abstraction layer.
`QSGRendererInterface::Metal (since Qt 5.14)` | `6` | Metal via a graphics abstraction layer.
`QSGRendererInterface::Null (since Qt 5.14)` | `7` | Null (no output) via a graphics abstraction layer.

### enum QSGRendererInterface::RenderMode

Constant | Value | Description
--- | --- | ---
`QSGRendererInterface::RenderMode2D` | `0` | Normal 2D rendering
`QSGRendererInterface::RenderMode2DNoDepthBuffer` | `1` | Normal 2D rendering with depth buffer disabled
`QSGRendererInterface::RenderMode3D` | `2` | Scene is rendered as part of a 3D graph

### enum QSGRendererInterface::Resource

Constant | Value | Description
--- | --- | ---

`QSGRendererInterface::DeviceResource`

`0`

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` | `1` | 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`

`2`

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` | `3` | The resource is a pointer to the active QPainter used by the scenegraph, when running with the software backend.
`QSGRendererInterface::RhiResource (since Qt 5.14)` | `4` | The resource is a pointer to the QRhi instance used by the scenegraph, when applicable.
`QSGRendererInterface::RhiSwapchainResource (since Qt 6.0)` | `5` | 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 (since Qt 6.0)` | `6` | 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 (since Qt 6.0)`

`7`

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 (since Qt 5.14)` | `8` | 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 (since Qt 5.14)` | `9` | The resource is a pointer to the QOpenGLContext used by the scenegraph (on the render thread), when applicable.
`QSGRendererInterface::DeviceContextResource (since Qt 5.14)` | `10` | The resource is a pointer to the device context used by the scenegraph, when applicable. For example, a `ID3D11DeviceContext *`.
`QSGRendererInterface::CommandEncoderResource (since Qt 5.14)` | `11` | 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 (since Qt 5.14)` | `12` | The resource is a pointer to the QVulkanInstance used by the scenegraph, when applicable.

`QSGRendererInterface::RenderPassResource (since Qt 5.14)`

`13`

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 (since Qt 6.4)` | `14` | 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 (since Qt 6.6)` | `15` | 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 (since Qt 6.6)` | `16` | 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`.

### enum QSGRendererInterface::ShaderCompilationType
flags QSGRendererInterface::ShaderCompilationTypes

Constant | Value | Description
--- | --- | ---
`QSGRendererInterface::RuntimeCompilation` | `0x01` | Runtime compilation of shader source code is supported
`QSGRendererInterface::OfflineCompilation` | `0x02` | Pre-compiled bytecode supported

The ShaderCompilationTypes type is a typedef for QFlags<ShaderCompilationType>. It stores an OR combination of ShaderCompilationType values.

### enum QSGRendererInterface::ShaderSourceType
flags QSGRendererInterface::ShaderSourceTypes

Constant | Value | Description
--- | --- | ---
`QSGRendererInterface::ShaderSourceString` | `0x01` | Shader source can be provided as a string in the corresponding properties of ShaderEffect
`QSGRendererInterface::ShaderSourceFile` | `0x02` | Local or resource files containing shader source code are supported
`QSGRendererInterface::ShaderByteCode` | `0x04` | Local or resource files containing shader bytecode are supported

The ShaderSourceTypes type is a typedef for QFlags<ShaderSourceType>. It stores an OR combination of ShaderSourceType values.

### enum QSGRendererInterface::ShaderType

Constant | Value | Description
--- | --- | ---
`QSGRendererInterface::UnknownShadingLanguage` | `0` | Not yet known due to no window and scenegraph associated
`QSGRendererInterface::GLSL` | `1` | GLSL or GLSL ES
`QSGRendererInterface::HLSL` | `2` | HLSL
`QSGRendererInterface::RhiShader (since Qt 5.14)` | `3` | Consumes QShader instances containing shader variants for multiple target languages and intermediate formats.

## Member Function Documentation

### `[virtual]` void *QSGRendererInterface::getResource(QQuickWindow *window, QSGRendererInterface::Resource resource) const

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.

### `[virtual]` void *QSGRendererInterface::getResource(QQuickWindow *window, const char *resource) const

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.

### `[pure virtual]` QSGRendererInterface::GraphicsApi QSGRendererInterface::graphicsApi() const

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

Note: This function can be called on any thread.

### `[static]` bool QSGRendererInterface::isApiRhiBased(QSGRendererInterface::GraphicsApi api)

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.

### `[pure virtual]` QSGRendererInterface::ShaderCompilationTypes QSGRendererInterface::shaderCompilationType() const

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.

See also QtQuick::GraphicsInfo.

### `[pure virtual]` QSGRendererInterface::ShaderSourceTypes QSGRendererInterface::shaderSourceType() const

Returns a bitmask of the supported ways of providing shader sources in ShaderEffect items.

Note: This function can be called on any thread.

See also QtQuick::GraphicsInfo.

### `[pure virtual]` QSGRendererInterface::ShaderType QSGRendererInterface::shaderType() const

Returns the shading language supported by the Qt Quick backend the application is using.

Note: This function can be called on any thread.

See also QtQuick::GraphicsInfo.