QVulkanFunctions Class Reference

The QVulkanFunctions class provides cross-platform access to the instance level core Vulkan 1.3 API. More...

Collaboration diagram for QVulkanFunctions:

Detailed Description

The QVulkanFunctions class provides cross-platform access to the instance level core Vulkan 1.3 API.

Since

5.10

\inmodule QtGui \wrapper

Qt and Qt applications do not link to any Vulkan libraries by default. Instead, all functions are resolved dynamically at run time. Each QVulkanInstance provides a QVulkanFunctions object retrievable via QVulkanInstance::functions(). This does not contain device level functions in order to avoid the potential overhead of an internal dispatching. Instead, functions that rely on a device, or a dispatchable child object of a device, are exposed via QVulkanDeviceFunctions and QVulkanInstance::deviceFunctions(). QVulkanFunctions and QVulkanDeviceFunctions together provides access to the full core Vulkan API, excluding any extensions.

Note

QVulkanFunctions instances cannot be constructed directly.

The typical usage is the following:

void Window::init()
{
    QVulkanInstance *inst = vulkanInstance();
    QVulkanFunctions *f = inst->functions();
    // ...
    uint32_t count = 0;
    VkResult err = f->vkEnumeratePhysicalDevices(inst->vkInstance(), &count, nullptr);
    // ...
}

Note

Windowing system interface (WSI) specifics and extensions are excluded. This class only covers core Vulkan commands, with the exception of instance creation, destruction, and function resolving, since such functionality is covered by QVulkanInstance itself.

To access additional functions, applications can use QVulkanInstance::getInstanceProcAddr() and vkGetDeviceProcAddr(). Applications can also decide to link to a Vulkan library directly, as platforms with an appropriate loader will typically export function symbols for the core commands. See \l{https://www.khronos.org/registry/vulkan/specs/1.0/man/html/vkGetInstanceProcAddr.html}{the man page for vkGetInstanceProcAddr} for more information.

Note

The member function prototypes for Vulkan 1.1, 1.2, and 1.3 commands are ifdefed with the appropriate {VK_VERSION_1_x} that is defined by the Vulkan headers. As such, these functions will only be callable by an application when the system's (on which the application is built) Vulkan header is new enough and it contains 1.1, 1.2, or 1.3 Vulkan API definitions. When building Qt from source, this has an additional consequence: the Vulkan headers on the build environment must also be 1.1, 1.2, and 1.3 compatible to get a Qt build that supports resolving the 1.1, 1.2, and 1.3 API commands. If neither of these conditions is met, applications will only be able to call the Vulkan 1.0 commands through QVulkanFunctions and QVulkanDeviceFunctions.

See also

QVulkanInstance, QVulkanDeviceFunctions, QWindow::setVulkanInstance(), QWindow::setSurfaceType()

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The documentation for this class was generated from the following file:

• qtbase/src/gui/vulkan/qvulkanfunctions.cpp (1e6367e65cb6d00f00d0befa2bf80463b7495e60)