feat(bindless): Implement transition command buffer

lsfg-vk-backend/src/lsfgvk.cpp

@@ -75,7 +75,7 @@ Context::Context(
         { width, height },
         flowScale,
         performanceMode,
-        false /* TODO: HDR */
+        false
     };
 
     this->m_priv = std::make_unique<priv::Context>(priv::Context {
@@ -158,7 +158,11 @@ void Context::dispatch(uint32_t total) {
     // Dispatch main passes
     uint64_t prevInternal{};
     for (uint32_t i = 0; i < total; i++) {
-        const auto& transCmdbuf{ctx.pipeline.getCmdbufs().at(0)}; // FIXME: replace with actual buf
+        const auto& transCmdbuf{ctx.pipeline.buildTransCmdbuf(
+            vk.dld, *vk.device,
+            mapped->iteration,
+            i, total
+        )};
 
         // Transition command buffer to next timestamp
         if (i == 0) {
@@ -179,7 +183,7 @@ void Context::dispatch(uint32_t total) {
                 .pWaitSemaphores = i == 0 ? &*internal.first : &*sync.first,
                 .pWaitDstStageMask = &waitStage,
                 .commandBufferCount = 1,
-                .pCommandBuffers = &*transCmdbuf,
+                .pCommandBuffers = &transCmdbuf,
                 .signalSemaphoreCount = 1,
                 .pSignalSemaphores = &*internal.first
             }},

lsfg-vk-backend/src/modules/pipeline.cpp

@@ -805,3 +805,45 @@ Pipeline::Pipeline(
     LOG_DEBUG("  Recorded command buffers for pipeline execution")
     LOG_DEBUG("Finished building pipeline")
 }
+
+vk::CommandBuffer Pipeline::buildTransCmdbuf(
+    const vk::detail::DispatchLoaderDynamic& dld,
+    const vk::Device& device,
+    uint32_t iteration,
+    uint32_t index,
+    uint32_t total
+) {
+    const bool persist{total > 8};
+    const uint64_t key{persist ? ((static_cast<uint64_t>(index) << 32) | total) : index};
+
+    if (persist && this->m_transCmdbufs.contains(key))
+        return *this->m_transCmdbufs.at(key);
+
+    auto& cmdbuf{this->m_transCmdbufs[key]};
+    cmdbuf = vkhelper::createCommandBuffer(
+        dld,
+        device,
+        *this->m_pool
+    );
+
+    cmdbuf->begin({
+        .flags = persist ? vk::CommandBufferUsageFlagBits::eSimultaneousUse :
+            vk::CommandBufferUsageFlagBits::eOneTimeSubmit
+    }, dld);
+
+    const UniformBuffer buf{
+        .timestamp = static_cast<float>(index + 1) / static_cast<float>(total + 1),
+        .iteration = iteration
+    };
+    cmdbuf->updateBuffer(
+        *this->m_descriptorSet.buffer.first,
+        0,
+        4,
+        static_cast<const void*>(&buf.timestamp),
+        dld
+    );
+
+    cmdbuf->end(dld);
+
+    return *cmdbuf;
+}

lsfg-vk-backend/src/modules/pipeline.hpp

@@ -18,8 +18,6 @@
 
 namespace lsfgvk::pipeline {
 
-    // TODO: Improve API design
-
     /// Handle to an external image
     struct ExternalImage {
         /// Image Extent
@@ -60,7 +58,7 @@ namespace lsfgvk::pipeline {
         /// Create a new pipeline
         ///
         /// @param dld Vulkan dispatch loader
-        /// @param dev Vulkan device
+        /// @param device Vulkan device
         /// @param physdev Vulkan physical device
         /// @param queue Vulkan compute queue
         /// @param queueFamilyIndex Compute queue family index
@@ -74,7 +72,7 @@ namespace lsfgvk::pipeline {
         ///
         explicit Pipeline(
             const vk::detail::DispatchLoaderDynamic& dld,
-            const vk::Device& dev,
+            const vk::Device& device,
             const vk::PhysicalDevice& physdev,
             const vk::Queue& queue,
             uint32_t queueFamilyIndex,
@@ -118,6 +116,24 @@ namespace lsfgvk::pipeline {
             return this->m_cmdbufs;
         }
 
+        ///
+        /// Build a transition command buffer
+        ///
+        /// @param dld Vulkan dispatch loader
+        /// @param device Vulkan device
+        /// @param iteration Current iteration
+        /// @param index Index of the iteration
+        /// @param total Total iterations
+        /// @return Command buffer handle
+        ///
+        vk::CommandBuffer buildTransCmdbuf(
+            const vk::detail::DispatchLoaderDynamic& dld,
+            const vk::Device& device,
+            uint32_t iteration,
+            uint32_t index,
+            uint32_t total
+        );
+
     private:
         /// Vulkan descriptor set & pipeline layout
         struct Layout {
@@ -203,6 +219,7 @@ namespace lsfgvk::pipeline {
 
         vk::UniqueCommandPool m_pool;
         std::vector<vk::UniqueCommandBuffer> m_cmdbufs;
+        std::unordered_map<uint64_t, vk::UniqueCommandBuffer> m_transCmdbufs;
     };
 
 }