Dynamic Rendering

In previous versions of Vulkan, we would need to create framebuffers to bind our image views to a render pass. However, with the introduction of dynamic rendering in Vulkan 1.3, we can now render directly to image views without creating framebuffers or render passes.

Introduction to Dynamic Rendering

Dynamic rendering simplifies the rendering process by eliminating the need for render pass and framebuffer objects. Instead, we can specify the color, depth, and stencil attachments directly when we begin rendering.

This approach offers several advantages: - Simplified code with fewer objects to manage - More flexibility in changing attachments during rendering - Better compatibility with modern rendering techniques

Let’s see how this works in practice. We’ll be using the vk::RenderingAttachmentInfo and vk::RenderingInfo structures to specify our attachments and rendering parameters.

Command Buffer Recording with Dynamic Rendering

In the next chapter, we’ll create command buffers and record rendering commands. Here’s a preview of how we’ll use dynamic rendering:

void recordCommandBuffer(uint32_t imageIndex) {
    commandBuffer.begin({});

    // Transition the image layout for rendering
    transition_image_layout(
        imageIndex,
        vk::ImageLayout::eUndefined,
        vk::ImageLayout::eColorAttachmentOptimal,
        {},
        vk::AccessFlagBits2::eColorAttachmentWrite,
        vk::PipelineStageFlagBits2::eTopOfPipe,
        vk::PipelineStageFlagBits2::eColorAttachmentOutput
    );

    // Set up the color attachment
    vk::ClearValue clearColor = vk::ClearColorValue(0.0f, 0.0f, 0.0f, 1.0f);
    vk::RenderingAttachmentInfo attachmentInfo = {
        .imageView = swapChainImageViews[imageIndex],
        .imageLayout = vk::ImageLayout::eColorAttachmentOptimal,
        .loadOp = vk::AttachmentLoadOp::eClear,
        .storeOp = vk::AttachmentStoreOp::eStore,
        .clearValue = clearColor
    };

    // Set up the rendering info
    vk::RenderingInfo renderingInfo = {
        .renderArea = { .offset = { 0, 0 }, .extent = swapChainExtent },
        .layerCount = 1,
        .colorAttachmentCount = 1,
        .pColorAttachments = &attachmentInfo
    };

    // Begin rendering
    commandBuffer.beginRendering(renderingInfo);

    // Rendering commands will go here

    // End rendering
    commandBuffer.endRendering();

    // Transition the image layout for presentation
    transition_image_layout(
        imageIndex,
        vk::ImageLayout::eColorAttachmentOptimal,
        vk::ImageLayout::ePresentSrcKHR,
        vk::AccessFlagBits2::eColorAttachmentWrite,
        {},
        vk::PipelineStageFlagBits2::eColorAttachmentOutput,
        vk::PipelineStageFlagBits2::eBottomOfPipe
    );

    commandBuffer.end();
}

As you can see, we directly specify the image view to render to in the vk::RenderingAttachmentInfo structure. We also specify the load and store operations, similar to what we would do in a render pass. The vk::RenderingInfo structure then combines this with other rendering parameters.

With this approach, we don’t need to create framebuffers or render passes, which simplifies our code and gives us more flexibility.

In the next chapter, we’ll create command buffers and write the first actual drawing commands using dynamic rendering.

C++ code / Slang shader / GLSL Vertex shader / GLSL Fragment shader