Add Vulkan Descriptor-Update batching

Allows multiple descriptor operations to be batched up and dispatched in
one API call rather than scattered through out the code base.

CMakeLists.txt

@@ -241,12 +241,14 @@ if(ENABLE_VULKAN)
 	set(RENDERER_VK_INCLUDE_FILES include/renderer_vk/renderer_vk.hpp
 		include/renderer_vk/vk_api.hpp include/renderer_vk/vk_debug.hpp
 		include/renderer_vk/vk_descriptor_heap.hpp
+		include/renderer_vk/vk_descriptor_update_batch.hpp
 		include/renderer_vk/vk_memory.hpp include/renderer_vk/vk_pica.hpp
 	)
 
 	set(RENDERER_VK_SOURCE_FILES src/core/renderer_vk/renderer_vk.cpp
 		src/core/renderer_vk/vk_api.cpp src/core/renderer_vk/vk_debug.cpp
 		src/core/renderer_vk/vk_descriptor_heap.cpp
+		src/core/renderer_vk/vk_descriptor_update_batch.cpp
 		src/core/renderer_vk/vk_memory.cpp src/core/renderer_vk/vk_pica.cpp
 	)
 

include/renderer_vk/vk_descriptor_update_batch.hpp

@@ -0,0 +1,62 @@
+#pragma once
+
+#include <memory>
+#include <optional>
+#include <variant>
+
+#include "helpers.hpp"
+#include "vk_api.hpp"
+
+namespace Vulkan {
+	// Implements a re-usable structure for batching up descriptor writes with a
+	// finite amount of space for both convenience and to reduce the overall amount
+	// of API calls to `vkUpdateDescriptorSets`
+	class DescriptorUpdateBatch {
+	  private:
+		const vk::Device device;
+
+		const usize descriptorWriteMax;
+		const usize descriptorCopyMax;
+
+		using DescriptorInfoUnion = std::variant<vk::DescriptorImageInfo, vk::DescriptorBufferInfo, vk::BufferView>;
+
+		// Todo: Maybe some kind of hash so that these structures can be re-used
+		// among descriptor writes.
+		std::unique_ptr<DescriptorInfoUnion[]> descriptorInfos;
+		std::unique_ptr<vk::WriteDescriptorSet[]> descriptorWrites;
+		std::unique_ptr<vk::CopyDescriptorSet[]> descriptorCopies;
+
+		usize descriptorWriteEnd = 0;
+		usize descriptorCopyEnd = 0;
+
+		DescriptorUpdateBatch(vk::Device device, usize descriptorWriteMax, usize descriptorCopyMax)
+			: device(device), descriptorWriteMax(descriptorWriteMax), descriptorCopyMax(descriptorCopyMax) {}
+
+	  public:
+		~DescriptorUpdateBatch() = default;
+
+		DescriptorUpdateBatch(DescriptorUpdateBatch&&) = default;
+
+		void flush();
+
+		void addImage(
+			vk::DescriptorSet targetDescriptor, u8 targetBinding, vk::ImageView imageView, vk::ImageLayout imageLayout = vk::ImageLayout::eGeneral
+		);
+		void addSampler(vk::DescriptorSet targetDescriptor, u8 targetBinding, vk::Sampler sampler);
+
+		void addImageSampler(
+			vk::DescriptorSet targetDescriptor, u8 targetBinding, vk::ImageView imageView, vk::Sampler sampler,
+			vk::ImageLayout imageLayout = vk::ImageLayout::eShaderReadOnlyOptimal
+		);
+		void addBuffer(
+			vk::DescriptorSet targetDescriptor, u8 targetBinding, vk::Buffer buffer, vk::DeviceSize offset, vk::DeviceSize size = VK_WHOLE_SIZE
+		);
+
+		void copyBinding(
+			vk::DescriptorSet sourceDescriptor, vk::DescriptorSet targetDescriptor, u8 sourceBinding, u8 targetBinding, u8 sourceArrayElement = 0,
+			u8 targetArrayElement = 0, u8 descriptorCount = 1
+		);
+
+		static std::optional<DescriptorUpdateBatch> create(vk::Device device, usize descriptorWriteMax = 256, usize descriptorCopyMax = 256);
+	};
+}  // namespace Vulkan

src/core/renderer_vk/vk_descriptor_update_batch.cpp

@@ -0,0 +1,98 @@
+#include "renderer_vk/vk_descriptor_update_batch.hpp"
+
+#include <memory>
+#include <span>
+
+namespace Vulkan {
+
+	void DescriptorUpdateBatch::flush() {
+		device.updateDescriptorSets({std::span(descriptorWrites.get(), descriptorWriteEnd)}, {std::span(descriptorCopies.get(), descriptorCopyEnd)});
+
+		descriptorWriteEnd = 0;
+		descriptorCopyEnd = 0;
+	}
+
+	void DescriptorUpdateBatch::addImage(vk::DescriptorSet targetDescriptor, u8 targetBinding, vk::ImageView imageView, vk::ImageLayout imageLayout) {
+		if (descriptorWriteEnd >= descriptorWriteMax) {
+			flush();
+		}
+
+		const auto& imageInfo = descriptorInfos[descriptorWriteEnd].emplace<vk::DescriptorImageInfo>(vk::Sampler(), imageView, imageLayout);
+
+		descriptorWrites[descriptorWriteEnd] =
+			vk::WriteDescriptorSet(targetDescriptor, targetBinding, 0, 1, vk::DescriptorType::eSampledImage, &imageInfo, nullptr, nullptr);
+
+		++descriptorWriteEnd;
+	}
+
+	void DescriptorUpdateBatch::addSampler(vk::DescriptorSet targetDescriptor, u8 targetBinding, vk::Sampler sampler) {
+		if (descriptorWriteEnd >= descriptorWriteMax) {
+			flush();
+		}
+
+		const auto& imageInfo = descriptorInfos[descriptorWriteEnd].emplace<vk::DescriptorImageInfo>(sampler, vk::ImageView(), vk::ImageLayout());
+
+		descriptorWrites[descriptorWriteEnd] =
+			vk::WriteDescriptorSet(targetDescriptor, targetBinding, 0, 1, vk::DescriptorType::eSampler, &imageInfo, nullptr, nullptr);
+
+		++descriptorWriteEnd;
+	}
+
+	void DescriptorUpdateBatch::addImageSampler(
+		vk::DescriptorSet targetDescriptor, u8 targetBinding, vk::ImageView imageView, vk::Sampler sampler, vk::ImageLayout imageLayout
+	) {
+		if (descriptorWriteEnd >= descriptorWriteMax) {
+			flush();
+		}
+
+		const auto& imageInfo = descriptorInfos[descriptorWriteEnd].emplace<vk::DescriptorImageInfo>(sampler, imageView, imageLayout);
+
+		descriptorWrites[descriptorWriteEnd] =
+			vk::WriteDescriptorSet(targetDescriptor, targetBinding, 0, 1, vk::DescriptorType::eCombinedImageSampler, &imageInfo, nullptr, nullptr);
+
+		++descriptorWriteEnd;
+	}
+
+	void DescriptorUpdateBatch::addBuffer(
+		vk::DescriptorSet targetDescriptor, u8 targetBinding, vk::Buffer buffer, vk::DeviceSize offset, vk::DeviceSize size
+	) {
+		if (descriptorWriteEnd >= descriptorWriteMax) {
+			flush();
+		}
+
+		const auto& bufferInfo = descriptorInfos[descriptorWriteEnd].emplace<vk::DescriptorBufferInfo>(buffer, offset, size);
+
+		descriptorWrites[descriptorWriteEnd] =
+			vk::WriteDescriptorSet(targetDescriptor, targetBinding, 0, 1, vk::DescriptorType::eStorageImage, nullptr, &bufferInfo, nullptr);
+
+		++descriptorWriteEnd;
+	}
+
+	void DescriptorUpdateBatch::copyBinding(
+		vk::DescriptorSet sourceDescriptor, vk::DescriptorSet targetDescriptor, u8 sourceBinding, u8 targetBinding, u8 sourceArrayElement,
+		u8 targetArrayElement, u8 descriptorCount
+	) {
+		if (descriptorCopyEnd >= descriptorCopyMax) {
+			flush();
+		}
+
+		descriptorCopies[descriptorCopyEnd] = vk::CopyDescriptorSet(
+			sourceDescriptor, sourceBinding, sourceArrayElement, targetDescriptor, targetBinding, targetArrayElement, descriptorCount
+		);
+
+		++descriptorCopyEnd;
+	}
+
+	std::optional<DescriptorUpdateBatch> DescriptorUpdateBatch::create(vk::Device device, usize descriptorWriteMax, usize descriptorCopyMax)
+
+	{
+		DescriptorUpdateBatch newDescriptorUpdateBatch(device, descriptorWriteMax, descriptorCopyMax);
+
+		newDescriptorUpdateBatch.descriptorInfos = std::make_unique<DescriptorInfoUnion[]>(descriptorWriteMax);
+		newDescriptorUpdateBatch.descriptorWrites = std::make_unique<vk::WriteDescriptorSet[]>(descriptorWriteMax);
+		newDescriptorUpdateBatch.descriptorCopies = std::make_unique<vk::CopyDescriptorSet[]>(descriptorCopyMax);
+
+		return {std::move(newDescriptorUpdateBatch)};
+	}
+
+}  // namespace Vulkan