DescriptorManager.h

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/* Copyright (C) 2024 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef INCLUDED_RENDERER_BACKEND_VULKAN_DESCRIPTORMANAGER
#define INCLUDED_RENDERER_BACKEND_VULKAN_DESCRIPTORMANAGER
 
#include "ps/CStrIntern.h"
#include "renderer/backend/Sampler.h"
#include "renderer/backend/vulkan/Device.h"
#include "renderer/backend/vulkan/Texture.h"
 
#include <glad/vulkan.h>
#include <limits>
#include <memory>
#include <unordered_map>
#include <utility>
#include <vector>
 
namespace Renderer
{
 
namespace Backend
{
 
namespace Vulkan
{
 
class CDevice;
 
class CDescriptorManager
{
public:
    CDescriptorManager(CDevice* device, const bool useDescriptorIndexing);
    ~CDescriptorManager();
 
    bool UseDescriptorIndexing() const { return m_UseDescriptorIndexing; }
 
    /**
     * @return a single type descriptor set layout with the number of bindings
     * equals to the size. The returned layout is owned by the manager.
     */
    VkDescriptorSetLayout GetSingleTypeDescritorSetLayout(
        VkDescriptorType type, const uint32_t size);
 
    VkDescriptorSet GetSingleTypeDescritorSet(
        VkDescriptorType type, VkDescriptorSetLayout layout,
        const std::vector<DeviceObjectUID>& texturesUID,
        const std::vector<CTexture*>& textures);
 
    uint32_t GetUniformSet() const;
 
    uint32_t GetTextureDescriptor(CTexture* texture);
 
    void OnTextureDestroy(const DeviceObjectUID uid);
 
    const VkDescriptorSetLayout& GetDescriptorIndexingSetLayout() const { return m_DescriptorIndexingSetLayout; }
    const VkDescriptorSetLayout& GetUniformDescriptorSetLayout() const { return m_UniformDescriptorSetLayout; }
    const VkDescriptorSet& GetDescriptorIndexingSet() { return m_DescriptorIndexingSet; }
 
    const std::vector<VkDescriptorSetLayout>& GetDescriptorSetLayouts() const { return m_DescriptorSetLayouts; }
 
private:
    struct SingleTypePool
    {
        VkDescriptorSetLayout layout;
        VkDescriptorPool pool;
        int16_t firstFreeIndex = 0;
        static constexpr int16_t INVALID_INDEX = -1;
        struct Element
        {
            VkDescriptorSet set = VK_NULL_HANDLE;
            uint32_t version = 0;
            int16_t nextFreeIndex = INVALID_INDEX;
        };
        std::vector<Element> elements;
    };
    SingleTypePool& GetSingleTypePool(const VkDescriptorType type, const uint32_t size);
 
    std::pair<VkDescriptorSet, bool> GetSingleTypeDescritorSetImpl(
        VkDescriptorType type, VkDescriptorSetLayout layout,
        const std::vector<DeviceObjectUID>& uids);
 
    CDevice* m_Device = nullptr;
 
    bool m_UseDescriptorIndexing = false;
 
    VkDescriptorPool m_DescriptorIndexingPool = VK_NULL_HANDLE;
    VkDescriptorSet m_DescriptorIndexingSet = VK_NULL_HANDLE;
    VkDescriptorSetLayout m_DescriptorIndexingSetLayout = VK_NULL_HANDLE;
    VkDescriptorSetLayout m_UniformDescriptorSetLayout = VK_NULL_HANDLE;
    std::vector<VkDescriptorSetLayout> m_DescriptorSetLayouts;
 
    static constexpr uint32_t DESCRIPTOR_INDEXING_BINDING_SIZE = 16384;
    static constexpr uint32_t NUMBER_OF_BINDINGS_PER_DESCRIPTOR_INDEXING_SET = 3;
 
    struct DescriptorIndexingBindingMap
    {
        static_assert(std::numeric_limits<int16_t>::max() >= DESCRIPTOR_INDEXING_BINDING_SIZE);
        int16_t firstFreeIndex = 0;
        std::vector<int16_t> elements;
        std::unordered_map<DeviceObjectUID, int16_t> map;
    };
    std::array<DescriptorIndexingBindingMap, NUMBER_OF_BINDINGS_PER_DESCRIPTOR_INDEXING_SET>
        m_DescriptorIndexingBindings;
    std::unordered_map<DeviceObjectUID, uint32_t> m_TextureToBindingMap;
 
    std::unordered_map<VkDescriptorType, std::vector<SingleTypePool>> m_SingleTypePools;
    struct SingleTypePoolReference
    {
        VkDescriptorType type = VK_DESCRIPTOR_TYPE_MAX_ENUM;
        uint32_t version = 0;
        int16_t elementIndex = SingleTypePool::INVALID_INDEX;
        uint8_t size = 0;
    };
    std::unordered_map<DeviceObjectUID, std::vector<SingleTypePoolReference>> m_UIDToSingleTypePoolMap;
 
    using SingleTypeCacheKey = std::pair<VkDescriptorSetLayout, std::vector<DeviceObjectUID>>;
    struct SingleTypeCacheKeyHash
    {
        size_t operator()(const SingleTypeCacheKey& key) const;
    };
    std::unordered_map<SingleTypeCacheKey, VkDescriptorSet, SingleTypeCacheKeyHash> m_SingleTypeSets;
 
    std::unique_ptr<ITexture> m_ErrorTexture;
};
 
// TODO: ideally we might want to separate a set and its mapping.
template<typename DeviceObject>
class CSingleTypeDescriptorSetBinding
{
public:
    CSingleTypeDescriptorSetBinding(CDevice* device, const VkDescriptorType type,
        const uint32_t size, std::unordered_map<CStrIntern, uint32_t> mapping)
        : m_Device{device}, m_Type{type}, m_Mapping{std::move(mapping)}
    {
        m_BoundDeviceObjects.resize(size);
        m_BoundUIDs.resize(size);
        m_DescriptorSetLayout =
            m_Device->GetDescriptorManager().GetSingleTypeDescritorSetLayout(m_Type, size);
    }
 
    int32_t GetBindingSlot(const CStrIntern name) const
    {
        const auto it = m_Mapping.find(name);
        return it != m_Mapping.end() ? it->second : -1;
    }
 
    void SetObject(const int32_t bindingSlot, DeviceObject* object)
    {
        if (m_BoundUIDs[bindingSlot] == object->GetUID())
            return;
        m_BoundUIDs[bindingSlot] = object->GetUID();
        m_BoundDeviceObjects[bindingSlot] = object;
        m_Outdated = true;
    }
 
    bool IsOutdated() const { return m_Outdated; }
 
    VkDescriptorSet UpdateAndReturnDescriptorSet()
    {
        ENSURE(m_Outdated);
        m_Outdated = false;
 
        VkDescriptorSet descriptorSet =
            m_Device->GetDescriptorManager().GetSingleTypeDescritorSet(
                m_Type, m_DescriptorSetLayout, m_BoundUIDs, m_BoundDeviceObjects);
        ENSURE(descriptorSet != VK_NULL_HANDLE);
 
        return descriptorSet;
    }
 
    void Unbind()
    {
        std::fill(m_BoundDeviceObjects.begin(), m_BoundDeviceObjects.end(), nullptr);
        std::fill(m_BoundUIDs.begin(), m_BoundUIDs.end(), INVALID_DEVICE_OBJECT_UID);
        m_Outdated = true;
    }
 
    VkDescriptorSetLayout GetDescriptorSetLayout() { return m_DescriptorSetLayout; }
 
    const std::vector<DeviceObject*>& GetBoundDeviceObjects() const { return m_BoundDeviceObjects; }
 
private:
    CDevice* const m_Device;
    const VkDescriptorType m_Type;
    const std::unordered_map<CStrIntern, uint32_t> m_Mapping;
 
    bool m_Outdated{true};
 
    VkDescriptorSetLayout m_DescriptorSetLayout{VK_NULL_HANDLE};
 
    std::vector<DeviceObject*> m_BoundDeviceObjects;
    std::vector<DeviceObjectUID> m_BoundUIDs;
};
 
} // namespace Vulkan
 
} // namespace Backend
 
} // namespace Renderer
 
#endif // INCLUDED_RENDERER_BACKEND_VULKAN_DESCRIPTORMANAGER