vk_update_descriptor: Upload descriptor sets data directly

Instead of copying to a temporary payload before sending the update task
to the worker thread, insert elements to the payload directly.

src/video_core/renderer_vulkan/vk_rasterizer.cpp

@@ -1154,7 +1154,7 @@ void RasterizerVulkan::SetupTexture(const Tegra::Texture::FullTextureInfo& textu
     const auto sampler = sampler_cache.GetSampler(texture.tsc);
     update_descriptor_queue.AddSampledImage(sampler, image_view);
 
-    const auto image_layout = update_descriptor_queue.GetLastImageLayout();
+    VkImageLayout* const image_layout = update_descriptor_queue.LastImageLayout();
     *image_layout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
     sampled_views.push_back(ImageView{std::move(view), image_layout});
 }
@@ -1180,7 +1180,7 @@ void RasterizerVulkan::SetupImage(const Tegra::Texture::TICEntry& tic, const Ima
         view->GetImageView(tic.x_source, tic.y_source, tic.z_source, tic.w_source);
     update_descriptor_queue.AddImage(image_view);
 
-    const auto image_layout = update_descriptor_queue.GetLastImageLayout();
+    VkImageLayout* const image_layout = update_descriptor_queue.LastImageLayout();
     *image_layout = VK_IMAGE_LAYOUT_GENERAL;
     image_views.push_back(ImageView{std::move(view), image_layout});
 }

src/video_core/renderer_vulkan/vk_update_descriptor.cpp

@@ -24,35 +24,25 @@ void VKUpdateDescriptorQueue::TickFrame() {
 }
 
 void VKUpdateDescriptorQueue::Acquire() {
-    entries.clear();
-}
+    // Minimum number of entries required.
+    // This is the maximum number of entries a single draw call migth use.
+    static constexpr std::size_t MIN_ENTRIES = 0x400;
 
-void VKUpdateDescriptorQueue::Send(VkDescriptorUpdateTemplateKHR update_template,
-                                   VkDescriptorSet set) {
-    if (payload.size() + entries.size() >= payload.max_size()) {
+    if (payload.size() + MIN_ENTRIES >= payload.max_size()) {
         LOG_WARNING(Render_Vulkan, "Payload overflow, waiting for worker thread");
         scheduler.WaitWorker();
         payload.clear();
     }
+    upload_start = &*payload.end();
+}
 
-    // TODO(Rodrigo): Rework to write the payload directly
-    const auto payload_start = payload.data() + payload.size();
-    for (const auto& entry : entries) {
-        if (const auto image = std::get_if<VkDescriptorImageInfo>(&entry)) {
-            payload.push_back(*image);
-        } else if (const auto buffer = std::get_if<VkDescriptorBufferInfo>(&entry)) {
-            payload.push_back(*buffer);
-        } else if (const auto texel = std::get_if<VkBufferView>(&entry)) {
-            payload.push_back(*texel);
-        } else {
-            UNREACHABLE();
-        }
-    }
-
-    scheduler.Record(
-        [payload_start, set, update_template, logical = &device.GetLogical()](vk::CommandBuffer) {
-            logical->UpdateDescriptorSet(set, update_template, payload_start);
-        });
+void VKUpdateDescriptorQueue::Send(VkDescriptorUpdateTemplateKHR update_template,
+                                   VkDescriptorSet set) {
+    const void* const data = upload_start;
+    const vk::Device* const logical = &device.GetLogical();
+    scheduler.Record([data, logical, set, update_template](vk::CommandBuffer) {
+        logical->UpdateDescriptorSet(set, update_template, data);
+    });
 }
 
 } // namespace Vulkan

src/video_core/renderer_vulkan/vk_update_descriptor.h

@@ -15,17 +15,13 @@ namespace Vulkan {
 class VKDevice;
 class VKScheduler;
 
-class DescriptorUpdateEntry {
-public:
-    explicit DescriptorUpdateEntry() {}
+struct DescriptorUpdateEntry {
+    DescriptorUpdateEntry(VkDescriptorImageInfo image_) : image{image_} {}
 
-    DescriptorUpdateEntry(VkDescriptorImageInfo image) : image{image} {}
+    DescriptorUpdateEntry(VkDescriptorBufferInfo buffer_) : buffer{buffer_} {}
 
-    DescriptorUpdateEntry(VkDescriptorBufferInfo buffer) : buffer{buffer} {}
+    DescriptorUpdateEntry(VkBufferView texel_buffer_) : texel_buffer{texel_buffer_} {}
 
-    DescriptorUpdateEntry(VkBufferView texel_buffer) : texel_buffer{texel_buffer} {}
-
-private:
     union {
         VkDescriptorImageInfo image;
         VkDescriptorBufferInfo buffer;
@@ -45,32 +41,34 @@ public:
     void Send(VkDescriptorUpdateTemplateKHR update_template, VkDescriptorSet set);
 
     void AddSampledImage(VkSampler sampler, VkImageView image_view) {
-        entries.emplace_back(VkDescriptorImageInfo{sampler, image_view, {}});
+        payload.emplace_back(VkDescriptorImageInfo{sampler, image_view, {}});
     }
 
     void AddImage(VkImageView image_view) {
-        entries.emplace_back(VkDescriptorImageInfo{{}, image_view, {}});
+        payload.emplace_back(VkDescriptorImageInfo{{}, image_view, {}});
     }
 
     void AddBuffer(VkBuffer buffer, u64 offset, std::size_t size) {
-        entries.emplace_back(VkDescriptorBufferInfo{buffer, offset, size});
+        payload.emplace_back(VkDescriptorBufferInfo{buffer, offset, size});
     }
 
     void AddTexelBuffer(VkBufferView texel_buffer) {
-        entries.emplace_back(texel_buffer);
+        payload.emplace_back(texel_buffer);
     }
 
-    VkImageLayout* GetLastImageLayout() {
-        return &std::get<VkDescriptorImageInfo>(entries.back()).imageLayout;
+    VkImageLayout* LastImageLayout() {
+        return &payload.back().image.imageLayout;
+    }
+
+    const VkImageLayout* LastImageLayout() const {
+        return &payload.back().image.imageLayout;
     }
 
 private:
-    using Variant = std::variant<VkDescriptorImageInfo, VkDescriptorBufferInfo, VkBufferView>;
-
     const VKDevice& device;
     VKScheduler& scheduler;
 
-    boost::container::static_vector<Variant, 0x400> entries;
+    const DescriptorUpdateEntry* upload_start = nullptr;
     boost::container::static_vector<DescriptorUpdateEntry, 0x10000> payload;
 };