Crafter.Graphics/src/module/Crafter.Graphics-VulkanBuffer.cppm

/*
Crafter®.Graphics
Copyright (C) 2025 Catcrafts®
Catcrafts.net

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3.0 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
*/

module;

#include <cstdint>
#include <vulkan/vulkan.h>
#include "../../lib/VulkanInitializers.hpp"

export module Crafter.Graphics:VulkanBuffer;
import :VulkanDevice;

namespace Crafter {
    /**
    * @brief VkBuffer holder.
    * Stores a value and handles buffer mapping and lifetime management.
    * @tparam T The value to store.
    */
    export template <typename T>
    class Buffer {
    public:
        T* value;
        VkDescriptorBufferInfo descriptor;
    public:
        /**
        * @brief Creates and initializes a Vulkan buffer with the specified usage and memory properties.
        *
        * This constructor allocates a buffer capable of holding `count` elements of type T.
        * The buffer usage and memory property flags control how the buffer will be used
        * and how its memory is managed.
        *
        * @param usageFlags Vulkan buffer usage flags that define allowed operations on the buffer
        *                   (e.g., vertex buffer, index buffer, uniform buffer).
        * @param memoryPropertyFlags Vulkan memory property flags specifying the desired memory
        *                            properties (e.g., device local, host visible).
        * @param count Number of elements to allocate space for in the buffer. The total buffer size
        *              will be `count * sizeof(T)`. Must be above 0.
        */
        Buffer(VkBufferUsageFlags usageFlags, VkMemoryPropertyFlags memoryPropertyFlags, std::uint32_t count = 1) {
            VkBufferCreateInfo bufferCreateInfo = vks::initializers::bufferCreateInfo(usageFlags, sizeof(T)*count);
            VulkanDevice::CHECK_VK_RESULT(vkCreateBuffer(VulkanDevice::device, &bufferCreateInfo, nullptr, &buffer));
        
            // Create the memory backing up the buffer handle
            VkMemoryRequirements memReqs;
            VkMemoryAllocateInfo memAlloc = vks::initializers::memoryAllocateInfo();
            vkGetBufferMemoryRequirements(VulkanDevice::device, buffer, &memReqs);
            memAlloc.allocationSize = memReqs.size;
            // Find a memory type index that fits the properties of the buffer
            memAlloc.memoryTypeIndex = VulkanDevice::GetMemoryType(memReqs.memoryTypeBits, memoryPropertyFlags);
            // If the buffer has VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT set we also need to enable the appropriate flag during allocation
            VkMemoryAllocateFlagsInfoKHR allocFlagsInfo{};
            if (usageFlags & VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT) {
                allocFlagsInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO_KHR;
                allocFlagsInfo.flags = VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT_KHR;
                memAlloc.pNext = &allocFlagsInfo;
            }
            VulkanDevice::CHECK_VK_RESULT(vkAllocateMemory(VulkanDevice::device, &memAlloc, nullptr, &memory));
        
            alignment = memReqs.alignment;
            usageFlags = usageFlags;
            memoryPropertyFlags = memoryPropertyFlags;
        
            descriptor.offset = 0;
            descriptor.buffer = buffer;
            descriptor.range = sizeof(T)*count;
        
            VulkanDevice::CHECK_VK_RESULT(vkBindBufferMemory(VulkanDevice::device, buffer, memory, 0));
            VulkanDevice::CHECK_VK_RESULT(vkMapMemory(VulkanDevice::device, memory, 0, sizeof(T)*count, 0, reinterpret_cast<void**>(&value)));
        }
        /**
        * @brief Frees all resources assosiacted with the buffer.
        */
        ~Buffer() {
            vkUnmapMemory(VulkanDevice::device, memory);
            vkDestroyBuffer(VulkanDevice::device, buffer, nullptr);
            vkFreeMemory(VulkanDevice::device, memory, nullptr);
        }
    private:
        VkDeviceSize alignment = 0;
		VkMemoryPropertyFlags memoryPropertyFlags;
        VkBufferUsageFlags usageFlags;
        VkBuffer buffer = VK_NULL_HANDLE;
        VkDeviceMemory memory = VK_NULL_HANDLE;
    };
}