Ktx2Loader.h

#pragma once
#include <cstdint>
#include <filesystem>
#include <memory>
#include <string>
#include <vector>
#include <vulkan/vulkan_core.h>
 
namespace Engine::Assets {
 
    namespace Textures
    {
        struct Ktx2TextureData {
            uint32_t baseWidth = 0;  
            uint32_t baseHeight = 0;  
            uint32_t sourceWidth = 0;  
            uint32_t sourceHeight = 0;  
            VkFormat vkFormat = VK_FORMAT_UNDEFINED;  
            uint32_t mipLevels = 0;  
            uint32_t sourceMipLevels = 0;  
            uint32_t sourceBaseMip = 0;  
            bool isCompressed = false;  
            std::vector<uint8_t> allData;  
            std::shared_ptr<void> externalDataOwner;  
            const uint8_t* externalData = nullptr;  
            std::vector<VkDeviceSize> mipOffsets;  
            std::vector<VkDeviceSize> mipSizes;  
            std::vector<uint32_t> mipWidths;  
            std::vector<uint32_t> mipHeights;  
            std::string uri;  

            [[nodiscard]] const uint8_t* bytes() const
            {
                return externalData != nullptr ? externalData : allData.data();
            }

            [[nodiscard]] bool hasBytes() const
            {
                return externalData != nullptr || !allData.empty();
            }

            void releaseBytes()
            {
                std::vector<uint8_t>().swap(allData);
                externalDataOwner.reset();
                externalData = nullptr;
            }
        };

        Ktx2TextureData extractMipRange(const Ktx2TextureData& source, uint32_t firstMip, uint32_t mipCount);
    }
 
    namespace Loaders
    {
        enum class Ktx2TextureType : uint32_t
        {
            BC6H_Unsigned = 0x8E8F,  
            BC6H_Signed = 0x8E8E,  
            BC7_RGBA = 0x8E8C,  
            BC7_SRGB = 0x8E8D,  
            BC4_Unsigned = 0x8DBB,  
            BC4_Signed = 0x8DBC,  
            BC5_Unsigned = 0x8DBD,  
            BC5_Signed = 0x8DBE,  
        };

        class Ktx2Loader {
        public:
            Ktx2Loader() = default;

            ~Ktx2Loader() = default;

            Textures::Ktx2TextureData load(const std::filesystem::path& filename);
        };
    }
 
} // namespace EngineCore