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Diffstat (limited to 'examples/vulkan/doc/src/hellovulkantriangle.qdoc')
-rw-r--r-- | examples/vulkan/doc/src/hellovulkantriangle.qdoc | 49 |
1 files changed, 46 insertions, 3 deletions
diff --git a/examples/vulkan/doc/src/hellovulkantriangle.qdoc b/examples/vulkan/doc/src/hellovulkantriangle.qdoc index 71d451c63a..bafa026ccd 100644 --- a/examples/vulkan/doc/src/hellovulkantriangle.qdoc +++ b/examples/vulkan/doc/src/hellovulkantriangle.qdoc @@ -7,13 +7,56 @@ \ingroup examples-vulkan \title Hello Vulkan Triangle Example \brief Shows the basics of rendering with QVulkanWindow and the Vulkan API. + \examplecategory {Graphics} - The \e{Hello Vulkan Triangle Example} builds on \l hellovulkanwindow. This - time a full graphics pipeline is created, including a vertex and fragment - shader. This pipeline is then used to render a triangle. + The \e{Hello Vulkan Triangle Example} creates a full graphics pipeline, + including a vertex and fragment shader, to render a triangle. \image hellovulkantriangle.png + \section1 Startup + + Each Qt application using Vulkan will have to have a \c{Vulkan instance} + which encapsulates application-level state and initializes a Vulkan library. + + A QVulkanWindow must always be associated with a QVulkanInstance and hence + the example performs instance creation before the window. The + QVulkanInstance object must also outlive the window. + + \snippet hellovulkantriangle/main.cpp 0 + + The example enables validation layers, when supported. When the requested + layers are not present, the request will be ignored. Additional layers and + extensions can be enabled in a similar manner. + + \snippet hellovulkantriangle/main.cpp 1 + + Once the instance is ready, it is time to create a window. Note that \c w + lives on the stack and is declared after \c inst. + + \section1 The QVulkanWindow Subclass + + To add custom functionality to a QVulkanWindow, subclassing is used. This + follows the existing patterns from QOpenGLWindow and QOpenGLWidget. + However, QVulkanWindow utilizes a separate QVulkanWindowRenderer object. + + The QVulkanWindow subclass reimplements the factory function + QVulkanWindow::createRenderer(). This simply returns a new instance of the + QVulkanWindowRenderer subclass. In order to be able to access various + Vulkan resources via the window object, a pointer to the window is passed + and stored via the constructor. + + \snippet hellovulkantriangle/main.cpp 2 + + \section1 The Actual Rendering + + QVulkanWindow subclasses queue their draw calls in their reimplementation + of QVulkanWindowRenderer::startNextFrame(). Once done, they are required to + call back QVulkanWindow::frameReady(). The example has no asynchronous + command generation, so the frameReady() call is made directly from + startNextFrame(). To get continuous updates, the example simply invokes + QWindow::requestUpdate() in order to schedule a repaint. + The example also demonstrates multisample antialiasing. Based on the supported sample counts reported by QVulkanWindow::supportedSampleCounts() the example chooses between 8x, 4x, or no multisampling. Once configured |