Enable multisampling and improve depth handling in rendering pipeline

- Set up MSAA sample count using `getMaxUsableSampleCount()` and integrate it throughout the pipeline.
- Add support for depth attachment in the pipeline with appropriate format detection.
- Refactor image layout transitions to handle color, depth, and multisampled images.
- Introduce `transition_image_layout_custom()` for flexible image layout transitions.
- Update rendering pass to include multisampled color and depth attachments with clear values.

Author: gpx1000

attachments/30_multisampling.cpp

@@ -181,6 +181,7 @@ class HelloTriangleApplication {
         setupDebugMessenger();
         createSurface();
         pickPhysicalDevice();
+        msaaSamples = getMaxUsableSampleCount();
         createLogicalDevice();
         createSwapChain();
         createImageViews();
@@ -528,7 +529,12 @@ class HelloTriangleApplication {
 
         pipelineLayout = vk::raii::PipelineLayout(device, pipelineLayoutInfo);
 
-        vk::PipelineRenderingCreateInfo pipelineRenderingCreateInfo{ .colorAttachmentCount = 1, .pColorAttachmentFormats = &swapChainImageFormat };
+        vk::Format depthFormat = findDepthFormat();
+        vk::PipelineRenderingCreateInfo pipelineRenderingCreateInfo{
+            .colorAttachmentCount = 1,
+            .pColorAttachmentFormats = &swapChainImageFormat,
+            .depthAttachmentFormat = depthFormat
+        };
         vk::GraphicsPipelineCreateInfo pipelineInfo{ .pNext = &pipelineRenderingCreateInfo,
             .stageCount = 2,
             .pStages = shaderStages,
@@ -1019,7 +1025,8 @@ class HelloTriangleApplication {
 
     void recordCommandBuffer(uint32_t imageIndex) {
         commandBuffers[currentFrame].begin({});
-        // Before starting rendering, transition the swapchain image to COLOR_ATTACHMENT_OPTIMAL
+        // Before starting rendering, transition the images to the appropriate layouts
+        // Transition the swapchain image to COLOR_ATTACHMENT_OPTIMAL
         transition_image_layout(
             imageIndex,
             vk::ImageLayout::eUndefined,
@@ -1029,19 +1036,60 @@ class HelloTriangleApplication {
             vk::PipelineStageFlagBits2::eTopOfPipe,                   // srcStage
             vk::PipelineStageFlagBits2::eColorAttachmentOutput        // dstStage
         );
+
+        // Transition the multisampled color image to COLOR_ATTACHMENT_OPTIMAL
+        transition_image_layout_custom(
+            colorImage,
+            vk::ImageLayout::eUndefined,
+            vk::ImageLayout::eColorAttachmentOptimal,
+            {},
+            vk::AccessFlagBits2::eColorAttachmentWrite,
+            vk::PipelineStageFlagBits2::eTopOfPipe,
+            vk::PipelineStageFlagBits2::eColorAttachmentOutput,
+            vk::ImageAspectFlagBits::eColor
+        );
+
+        // Transition the depth image to DEPTH_ATTACHMENT_OPTIMAL
+        transition_image_layout_custom(
+            depthImage,
+            vk::ImageLayout::eUndefined,
+            vk::ImageLayout::eDepthAttachmentOptimal,
+            {},
+            vk::AccessFlagBits2::eDepthStencilAttachmentWrite,
+            vk::PipelineStageFlagBits2::eTopOfPipe,
+            vk::PipelineStageFlagBits2::eEarlyFragmentTests,
+            vk::ImageAspectFlagBits::eDepth
+        );
         vk::ClearValue clearColor = vk::ClearColorValue(0.0f, 0.0f, 0.0f, 1.0f);
-        vk::RenderingAttachmentInfo attachmentInfo = {
-            .imageView = swapChainImageViews[imageIndex],
+        vk::ClearValue clearDepth = vk::ClearDepthStencilValue(1.0f, 0);
+
+        // Color attachment (multisampled) with resolve attachment
+        vk::RenderingAttachmentInfo colorAttachment = {
+            .imageView = colorImageView,
             .imageLayout = vk::ImageLayout::eColorAttachmentOptimal,
+            .resolveMode = vk::ResolveModeFlagBits::eAverage,
+            .resolveImageView = swapChainImageViews[imageIndex],
+            .resolveImageLayout = vk::ImageLayout::eColorAttachmentOptimal,
             .loadOp = vk::AttachmentLoadOp::eClear,
             .storeOp = vk::AttachmentStoreOp::eStore,
             .clearValue = clearColor
         };
+
+        // Depth attachment
+        vk::RenderingAttachmentInfo depthAttachment = {
+            .imageView = depthImageView,
+            .imageLayout = vk::ImageLayout::eDepthAttachmentOptimal,
+            .loadOp = vk::AttachmentLoadOp::eClear,
+            .storeOp = vk::AttachmentStoreOp::eDontCare,
+            .clearValue = clearDepth
+        };
+
         vk::RenderingInfo renderingInfo = {
             .renderArea = { .offset = { 0, 0 }, .extent = swapChainExtent },
             .layerCount = 1,
             .colorAttachmentCount = 1,
-            .pColorAttachments = &attachmentInfo
+            .pColorAttachments = &colorAttachment,
+            .pDepthAttachment = &depthAttachment
         };
         commandBuffers[currentFrame].beginRendering(renderingInfo);
         commandBuffers[currentFrame].bindPipeline(vk::PipelineBindPoint::eGraphics, *graphicsPipeline);
@@ -1052,7 +1100,9 @@ class HelloTriangleApplication {
         commandBuffers[currentFrame].bindDescriptorSets(vk::PipelineBindPoint::eGraphics, pipelineLayout, 0, *descriptorSets[currentFrame], nullptr);
         commandBuffers[currentFrame].drawIndexed(indices.size(), 1, 0, 0, 0);
         commandBuffers[currentFrame].endRendering();
-        // After rendering, transition the swapchain image to PRESENT_SRC
+        // After rendering, transition the images to appropriate layouts
+
+        // Transition the swapchain image to PRESENT_SRC
         transition_image_layout(
             imageIndex,
             vk::ImageLayout::eColorAttachmentOptimal,
@@ -1100,6 +1150,42 @@ class HelloTriangleApplication {
         commandBuffers[currentFrame].pipelineBarrier2(dependency_info);
     }
 
+    void transition_image_layout_custom(
+        vk::raii::Image& image,
+        vk::ImageLayout old_layout,
+        vk::ImageLayout new_layout,
+        vk::AccessFlags2 src_access_mask,
+        vk::AccessFlags2 dst_access_mask,
+        vk::PipelineStageFlags2 src_stage_mask,
+        vk::PipelineStageFlags2 dst_stage_mask,
+        vk::ImageAspectFlags aspect_mask
+        ) {
+        vk::ImageMemoryBarrier2 barrier = {
+            .srcStageMask = src_stage_mask,
+            .srcAccessMask = src_access_mask,
+            .dstStageMask = dst_stage_mask,
+            .dstAccessMask = dst_access_mask,
+            .oldLayout = old_layout,
+            .newLayout = new_layout,
+            .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+            .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+            .image = image,
+            .subresourceRange = {
+                .aspectMask = aspect_mask,
+                .baseMipLevel = 0,
+                .levelCount = 1,
+                .baseArrayLayer = 0,
+                .layerCount = 1
+            }
+        };
+        vk::DependencyInfo dependency_info = {
+            .dependencyFlags = {},
+            .imageMemoryBarrierCount = 1,
+            .pImageMemoryBarriers = &barrier
+        };
+        commandBuffers[currentFrame].pipelineBarrier2(dependency_info);
+    }
+
     void createSyncObjects() {
         presentCompleteSemaphore.clear();
         renderFinishedSemaphore.clear();