I’m building a video game engine using C++ as the coding language and Vulkan for graphics. I am trying to set up a generic renderer using Vulkan that is flexible and will render objects based on a vector that is supplied to it. The renderer will also handle the creation of the window using GLFW and use GLM for all relevant math calls. I am using the ASSIMP library to load 3d models and animations.

Here is a portion of the code:

Renderer.h:

#pragma once

#include <vulkan/vulkan.h>
#include "Window.h"
#include <vector>
#include <stdexcept>
#include <set>
#include <optional>
#include <iostream>
#include "Pipeline.h"
#include "Material.h"
#include "Mesh.h"

struct QueueFamilyIndices
{
	std::optional<uint32_t> graphicsFamily;
	std::optional<uint32_t> presentFamily;

	bool IsComplete()
	{
		return graphicsFamily.has_value() && presentFamily.has_value();
	}
};

struct SwapChainSupportDetails {
	VkSurfaceCapabilitiesKHR capabilities;
	std::vector<VkSurfaceFormatKHR> formats;
	std::vector<VkPresentModeKHR> presentModes;
};



class Renderer
{
public:
	Renderer();
	~Renderer();

	void Initialize(GLFWwindow* window);
	void Shutdown();

	void BeginFrame();
	void EndFrame();

	VkDescriptorSetLayout CreateDescriptorSetLayout();
	VkDescriptorPool CreateDescriptorPool(uint32_t maxSets);
	VkDevice* GetDevice();
	VkPhysicalDevice* GetPhysicalDevice();
	VkCommandPool* GetCommandPool();
	VkQueue* GetGraphicsQueue();
	VkCommandBuffer* GetCurrentCommandBuffer();
	std::shared_ptr<Pipeline> GetPipeline();
	void CreateGraphicsPipeline(Mesh* mesh, Material* material);
	VkDescriptorSetLayout CreateSamplerDescriptorSetLayout();

private:
	bool shutdownInProgress;
	uint32_t currentCmdBufferIndex = 0;
	std::vector<size_t> currentFramePerImage;

	std::vector<VkImage> swapChainImages;
	std::vector<VkImageView> swapChainImageViews;
	VkExtent2D swapChainExtent;
	VkRenderPass renderPass;
	uint32_t imageIndex;
	std::shared_ptr<Pipeline> pipeline;

	VkFormat swapChainImageFormat;

	std::vector<VkCommandBuffer> commandBuffers;

	void CreateImageViews();
	void CleanupImageViews();
	void CreateRenderPass();
	void CleanupRenderPass();

	void CreateSurface();
	void DestroySurface();

	void CreateInstance();
	void CleanupInstance();
	void ChoosePhysicalDevice();
	void CreateDevice();
	void CleanupDevice();
	void CreateSwapchain();
	void CleanupSwapchain();
	void CreateCommandPool();
	void CleanupCommandPool();
	void CreateFramebuffers();
	void CleanupFramebuffers();

	void CreateCommandBuffers();
	void CleanupCommandBuffers();

	void Present();

	

	

	GLFWwindow* window;
	VkInstance instance = VK_NULL_HANDLE;
	VkPhysicalDevice physicalDevice = VK_NULL_HANDLE;
	VkDevice device = VK_NULL_HANDLE;

	VkSurfaceKHR surface;
	VkSwapchainKHR swapchain;
	VkCommandPool commandPool;
	VkCommandBuffer currentCommandBuffer;

	std::vector<VkFramebuffer> framebuffers;

	// Additional Vulkan objects needed for rendering…

	const uint32_t kMaxFramesInFlight = 2;
	std::vector<VkSemaphore> imageAvailableSemaphores;
	std::vector<VkSemaphore> renderFinishedSemaphores;
	std::vector<VkFence> inFlightFences;
	size_t currentFrame;

	VkQueue graphicsQueue;
	VkQueue presentQueue;

	void CreateSyncObjects();
	void CleanupSyncObjects();

	SwapChainSupportDetails querySwapChainSupport(VkPhysicalDevice device, VkSurfaceKHR surface);
	VkSurfaceFormatKHR chooseSwapSurfaceFormat(const std::vector<VkSurfaceFormatKHR>& availableFormats);
	VkPresentModeKHR chooseSwapPresentMode(const std::vector<VkPresentModeKHR>& availablePresentModes);
	VkExtent2D chooseSwapExtent(const VkSurfaceCapabilitiesKHR& capabilities, GLFWwindow* window);

	std::vector<const char*> deviceExtensions = {
		VK_KHR_SWAPCHAIN_EXTENSION_NAME
	};

	std::vector<const char*> CheckPhysicalDeviceExtensionSupport(VkPhysicalDevice physicalDevice);
	QueueFamilyIndices GetQueueFamilyIndices(VkPhysicalDevice physicalDevice);
};

Engine.h:

#pragma once

#include "Window.h"
#include "Renderer.h"
#include "Scene.h"
#include <chrono>
#include <thread>

class Engine
{
public:
	Engine();
	~Engine();

	void Run();
	void Shutdown();

	int MaxFPS = 60;

private:

	void Initialize();
	void MainLoop();
	void Update(float deltaTime);
	void Render();

	Window window;
	Renderer renderer;
	Scene scene;
};

Engine.cpp:

#include "Engine.h"
#include "Terrain.h"
#include <iostream>

Engine::Engine()
{
	Initialize();
}

Engine::~Engine()
{
	Shutdown();
}

void Engine::Run()
{
	MainLoop();
}

void Engine::Initialize()
{
	// Initialize window, renderer, and scene
	window.Initialize();
	renderer.Initialize(window.GetWindow());
	scene.Initialize();

	VkDescriptorSetLayout descriptorSetLayout = renderer.CreateDescriptorSetLayout();
	//VkDescriptorPool descriptorPool = renderer.CreateDescriptorPool(1); // Assuming only one terrain object

	VkDescriptorSetLayout samplerDescriptorSetLayout = renderer.CreateSamplerDescriptorSetLayout(); // Use this new method to create a separate descriptor layout.
	VkDescriptorPool descriptorPool = renderer.CreateDescriptorPool(1);

	// Create a simple square tile GameObject
	GameObject* squareTile = new GameObject();
	squareTile->Initialize();

	// Define the square’s vertices and indices
	std::vector<Vertex> vertices = {
		{ { 0.0f, 0.0f, 0.0f }, { 1.0f, 0.0f, 0.0f } },  // Bottom left
		{ { 1.0f, 0.0f, 0.0f }, { 0.0f, 1.0f, 0.0f } },  // Bottom right
		{ { 1.0f, 1.0f, 0.0f }, { 0.0f, 0.0f, 1.0f } },  // Top right
		{ { 0.0f, 1.0f, 0.0f }, { 1.0f, 1.0f, 0.0f } },  // Top left
	};

	std::vector<uint32_t> indices = {
		0, 1, 2,  // First triangle
		0, 2, 3   // Second triangle
	};

	// Initialize mesh and material for the square tile
	squareTile->GetMesh()->Initialize(vertices, indices, *renderer.GetDevice(), *renderer.GetPhysicalDevice(), *renderer.GetCommandPool(), *renderer.GetGraphicsQueue());
	squareTile->GetMaterial()->Initialize("C:/shaders/vert_depth2.spv", "C:/shaders/frag_depth2.spv", "C:/textures/texture.jpg", *renderer.GetDevice(), descriptorSetLayout, samplerDescriptorSetLayout, descriptorPool, *renderer.GetPhysicalDevice(), *renderer.GetCommandPool(), *renderer.GetGraphicsQueue());

	// Add the square tile GameObject to the scene
	scene.AddGameObject(squareTile);

	/*Terrain terrain(0,10,1,renderer.GetDevice(), renderer.GetPhysicalDevice(), renderer.GetCommandPool(), renderer.GetGraphicsQueue());
	terrain.GenerateTerrain(descriptorSetLayout, samplerDescriptorSetLayout, descriptorPool);*/

	//scene.AddGameObject(terrain.GetTerrainObject());
	float deltaTime = window.GetDeltaTime();
}

void Engine::MainLoop()
{
	while (!window.ShouldClose())
	{
		window.PollEvents();

		float deltaTime = window.GetDeltaTime();
		Update(deltaTime);
		Render();

		auto sleep_duration = std::chrono::milliseconds(1000 / MaxFPS);
		std::this_thread::sleep_for(sleep_duration);
	}
}

void Engine::Update(float deltaTime)
{
	scene.Update(deltaTime);
}

void Engine::Render()
{
	renderer.BeginFrame();
	scene.Render(renderer);
	renderer.EndFrame();
}

void Engine::Shutdown()
{
	// Clean up resources in reverse order
	scene.Shutdown();
	renderer.Shutdown();
	window.Shutdown();
}

Material.h:

#pragma once

#include <vulkan/vulkan.h>
#include "Texture.h"
#include "Shader.h"
#include <stdexcept>
#include <memory> // Don’t forget to include <memory>

class Material
{
public:
    Material();
    ~Material();

    void Initialize(const std::string& vertShaderPath, const std::string& fragShaderPath, const std::string& texturePath, VkDevice device, VkDescriptorSetLayout descriptorSetLayout, VkDescriptorSetLayout samplerDescriptorSetLayout, VkDescriptorPool descriptorPool, VkPhysicalDevice physicalDevice, VkCommandPool commandPool, VkQueue graphicsQueue);
    void Cleanup();

    void LoadTexture(const std::string& filename, VkDevice device, VkPhysicalDevice physicalDevice, VkCommandPool commandPool, VkQueue graphicsQueue);
    void LoadShaders(const std::string& vertFilename, const std::string& fragFilename, VkDevice device);

    void UpdateBufferBinding(VkDescriptorSet descriptorSet, VkBuffer newBuffer, VkDevice device, VkDeviceSize devicesize);
    VkDescriptorSet GetDescriptorSet() const;
    VkPipelineLayout GetPipelineLayout() const;

    std::shared_ptr <Shader> GetvertexShader();
    std::shared_ptr <Shader> GetfragmentShader();

private:
    VkDevice device;
    std::shared_ptr <Shader> vertexShader;
    std::shared_ptr <Shader> fragmentShader;
    std::shared_ptr<Texture> texture;

    void CreateDescriptorSet(VkDescriptorSetLayout descriptorSetLayout, VkDescriptorPool descriptorPool);
    void CreatePipelineLayout(VkDescriptorSetLayout descriptorSetLayout);
    

    VkDescriptorSet descriptorSet;
    VkPipelineLayout pipelineLayout;
};

Material.cpp:

#include "Material.h"

Material::Material()
    : device(VK_NULL_HANDLE), descriptorSet(VK_NULL_HANDLE), pipelineLayout(VK_NULL_HANDLE)
{
}

Material::~Material()
{
    Cleanup();
}

void Material::Initialize(const std::string& vertShaderPath, const std::string& fragShaderPath, const std::string& texturePath, VkDevice device, VkDescriptorSetLayout descriptorSetLayout, VkDescriptorSetLayout samplerDescriptorSetLayout, VkDescriptorPool descriptorPool, VkPhysicalDevice physicalDevice, VkCommandPool commandPool, VkQueue graphicsQueue)
{
    this->device = device;

    // Load shaders and texture
    LoadTexture(texturePath, device, physicalDevice, commandPool, graphicsQueue);
    LoadShaders(vertShaderPath, fragShaderPath, device);

    // Create descriptor set and pipeline layout
    CreateDescriptorSet(samplerDescriptorSetLayout, descriptorPool);
    CreatePipelineLayout(descriptorSetLayout);
}

void Material::CreateDescriptorSet(VkDescriptorSetLayout descriptorSetLayout, VkDescriptorPool descriptorPool)
{
    VkDescriptorSetAllocateInfo allocInfo{};
    allocInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
    allocInfo.descriptorPool = descriptorPool;
    allocInfo.descriptorSetCount = 1;
    allocInfo.pSetLayouts = &descriptorSetLayout;

    if (vkAllocateDescriptorSets(device, &allocInfo, &descriptorSet) != VK_SUCCESS) {
        throw std::runtime_error("Failed to allocate descriptor sets!");
    }

    VkDescriptorImageInfo imageInfo{};
    imageInfo.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
    imageInfo.imageView = texture->GetImageView();
    imageInfo.sampler = texture->GetSampler();

    VkWriteDescriptorSet descriptorWrite{};
    descriptorWrite.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
    descriptorWrite.dstSet = descriptorSet;
    descriptorWrite.dstBinding = 0;
    descriptorWrite.dstArrayElement = 0;
    descriptorWrite.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
    descriptorWrite.descriptorCount = 1;
    descriptorWrite.pImageInfo = &imageInfo;

    vkUpdateDescriptorSets(device, 1, &descriptorWrite, 0, nullptr);
}

void Material::CreatePipelineLayout(VkDescriptorSetLayout descriptorSetLayout)
{
    VkPipelineLayoutCreateInfo pipelineLayoutInfo{};
    pipelineLayoutInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
    pipelineLayoutInfo.setLayoutCount = 1;
    pipelineLayoutInfo.pSetLayouts = &descriptorSetLayout;

    if (vkCreatePipelineLayout(device, &pipelineLayoutInfo, nullptr, &pipelineLayout) != VK_SUCCESS) {
        throw std::runtime_error("Failed to create pipeline layout!");
    }
}



void Material::Cleanup()
{
	// Clean up resources, if necessary
	// (depending on how Shader and Texture resources are managed)
}

VkDescriptorSet Material::GetDescriptorSet() const
{
	return descriptorSet;
}

VkPipelineLayout Material::GetPipelineLayout() const
{
	return pipelineLayout;
}

std::shared_ptr <Shader> Material::GetvertexShader()
{
    return vertexShader;
}

std::shared_ptr <Shader> Material::GetfragmentShader()
{
    return fragmentShader;
}

void Material::LoadTexture(const std::string& filename, VkDevice device, VkPhysicalDevice physicalDevice, VkCommandPool commandPool, VkQueue graphicsQueue)
{
	texture = std::shared_ptr<Texture>(new Texture{}, Texture::Cleanup); // Create a new Texture using shared_ptr
	texture->LoadFromFile(filename, device, physicalDevice, commandPool, graphicsQueue);
}

void Material::LoadShaders(const std::string& vertFilename, const std::string& fragFilename, VkDevice device)
{
	vertexShader = std::shared_ptr<Shader>(new Shader, Shader::Cleanup);
	fragmentShader = std::shared_ptr<Shader>(new Shader, Shader::Cleanup);
	vertexShader->LoadFromFile(vertFilename, device, VK_SHADER_STAGE_VERTEX_BIT);
	fragmentShader->LoadFromFile(fragFilename, device, VK_SHADER_STAGE_FRAGMENT_BIT);
}

void Material::UpdateBufferBinding(VkDescriptorSet descriptorSet, VkBuffer newBuffer, VkDevice device, VkDeviceSize devicesize)
{
    VkDescriptorBufferInfo bufferInfo{};
    bufferInfo.buffer = newBuffer;
    bufferInfo.offset = 0;
    bufferInfo.range = devicesize;

    VkWriteDescriptorSet descriptorWrite{};
    descriptorWrite.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
    descriptorWrite.dstSet = descriptorSet;
    descriptorWrite.dstBinding = 0;
    descriptorWrite.dstArrayElement = 0;
    descriptorWrite.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
    descriptorWrite.descriptorCount = 1;
    descriptorWrite.pBufferInfo = &bufferInfo;

    vkUpdateDescriptorSets(device, 1, &descriptorWrite, 0, nullptr);
}

Texture.h:

#pragma once

#include <vulkan/vulkan.h>

#include "stb_image.h" // Include the stb_image header
#include "BufferUtils.h"
#include <string>

class Texture
{
public:
	Texture();
	~Texture();

	void LoadFromFile(const std::string& filename, VkDevice device, VkPhysicalDevice physicalDevice, VkCommandPool commandPool, VkQueue graphicsQueue);

	VkImageView GetImageView() const;
	VkSampler GetSampler() const;
	static void Cleanup(Texture* texture);

private:
	VkDevice device;
	VkImage image;
	VkDeviceMemory imageMemory;
	VkImageView imageView;
	VkSampler sampler;
	VkPhysicalDevice physicalDevice;
	VkCommandPool commandPool;
	VkQueue graphicsQueue;
	bool initialized = false;

	void CreateImage(uint32_t width, uint32_t height, uint32_t mipLevels, VkSampleCountFlagBits numSamples, VkFormat format, VkImageTiling tiling, VkImageUsageFlags usage, VkMemoryPropertyFlags properties);
	void TransitionImageLayout(VkImageLayout oldLayout, VkImageLayout newLayout, uint32_t mipLevels, VkSampleCountFlagBits numSamples);
	void CreateImageView(VkFormat format, VkImageAspectFlags aspectFlags, uint32_t mipLevels);
	void CreateSampler(uint32_t mipLevels);
	void CopyBufferToImage(VkBuffer buffer, uint32_t width, uint32_t height);
	

	// Additional helper functions for texture loading…
};

Texture.cpp:

#include "Texture.h"
#include "BufferUtils.h"
#include <iostream>

Texture::Texture()
	: device(VK_NULL_HANDLE), image(VK_NULL_HANDLE), imageMemory(VK_NULL_HANDLE), imageView(VK_NULL_HANDLE), sampler(VK_NULL_HANDLE)
{
}

Texture::~Texture()
{
}

void Texture::LoadFromFile(const std::string& filename, VkDevice device, VkPhysicalDevice physicalDevice, VkCommandPool commandPool, VkQueue graphicsQueue)
{
    this->device = device;
    this->physicalDevice = physicalDevice;
    this->commandPool = commandPool;
    this->graphicsQueue = graphicsQueue;
    this->initialized = true;

    // Load image from file using stb_image
    int width, height, channels;
    stbi_uc* pixels = stbi_load(filename.c_str(), &width, &height, &channels, STBI_rgb_alpha);
    if (!pixels)
    {
        throw std::runtime_error("Failed to load texture image!");
    }

    // Calculate the number of mip levels
    uint32_t mipLevels = static_cast<uint32_t>(std::floor(std::log2(std::max(width, height)))) + 1;

    // Create a buffer to store the image data
    VkDeviceSize imageSize = width * height * 4;
    VkBuffer stagingBuffer;
    VkDeviceMemory stagingBufferMemory;

    // Create the staging buffer for transferring image data
    BufferUtils::CreateBuffer(device, physicalDevice, imageSize, VK_BUFFER_USAGE_TRANSFER_SRC_BIT, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT, stagingBuffer, stagingBufferMemory);

    // Copy image data to the buffer
    void* bufferData;
    vkMapMemory(device, stagingBufferMemory, 0, imageSize, 0, &bufferData);
    memcpy(bufferData, pixels, static_cast<size_t>(imageSize));
    vkUnmapMemory(device, stagingBufferMemory);

    // Free the stb_image buffer
    stbi_image_free(pixels);

    // Create vkImage, copy buffer to image, and create imageView and sampler
    // …

    CreateImage(width, height, mipLevels, VK_SAMPLE_COUNT_1_BIT, VK_FORMAT_R8G8B8A8_SRGB, VK_IMAGE_TILING_OPTIMAL,
        VK_IMAGE_USAGE_TRANSFER_SRC_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
    CreateImageView(VK_FORMAT_R8G8B8A8_SRGB, VK_IMAGE_ASPECT_COLOR_BIT, mipLevels);
    CreateSampler(mipLevels);
    TransitionImageLayout(VK_IMAGE_LAYOUT_UNDEFINED, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, mipLevels, VK_SAMPLE_COUNT_1_BIT);  // Add this call

    CopyBufferToImage(stagingBuffer, width, height);

    // Cleanup the staging buffer and staging buffer memory
    // …

    // Destroy the staging buffer and free the staging buffer memory
    vkDestroyBuffer(device, stagingBuffer, nullptr);
    vkFreeMemory(device, stagingBufferMemory, nullptr);
}

void Texture::Cleanup(Texture* texture)
{
    // Put the content of the old Cleanup() method here
    // Make sure to replace this with texture keyword
    // …
}

VkImageView Texture::GetImageView() const
{
	return imageView;
}

VkSampler Texture::GetSampler() const
{
	return sampler;
}

void Texture::CreateImage(uint32_t width, uint32_t height, uint32_t mipLevels, VkSampleCountFlagBits numSamples, VkFormat format, VkImageTiling tiling, VkImageUsageFlags usage, VkMemoryPropertyFlags properties)
{
    VkImageCreateInfo imageInfo{};
    imageInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
    imageInfo.imageType = VK_IMAGE_TYPE_2D;
    imageInfo.extent.width = width;
    imageInfo.extent.height = height;
    imageInfo.extent.depth = 1;
    imageInfo.mipLevels = mipLevels;
    imageInfo.arrayLayers = 1;
    imageInfo.format = format;
    imageInfo.tiling = tiling;
    imageInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
    imageInfo.usage = usage;
    imageInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
    imageInfo.samples = numSamples;
    imageInfo.flags = 0;

    if (vkCreateImage(device, &imageInfo, nullptr, &image) != VK_SUCCESS)
    {
        throw std::runtime_error("Failed to create image!");
    }

    VkMemoryRequirements memRequirements;
    vkGetImageMemoryRequirements(device, image, &memRequirements);

    VkMemoryAllocateInfo allocInfo{};
    allocInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
    allocInfo.allocationSize = memRequirements.size;
    allocInfo.memoryTypeIndex = BufferUtils::FindMemoryType(physicalDevice, memRequirements.memoryTypeBits, properties);

    if (vkAllocateMemory(device, &allocInfo, nullptr, &imageMemory) != VK_SUCCESS)
    {
        throw std::runtime_error("Failed to allocate image memory!");
    }

    vkBindImageMemory(device, image, imageMemory, 0);
}

void Texture::TransitionImageLayout(VkImageLayout oldLayout, VkImageLayout newLayout, uint32_t mipLevels, VkSampleCountFlagBits numSamples)
{
    // Create a one-time-use command buffer
    VkCommandBufferAllocateInfo allocInfo{};
    allocInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
    allocInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
    allocInfo.commandPool = commandPool;
    allocInfo.commandBufferCount = 1;

    VkCommandBuffer commandBuffer;
    vkAllocateCommandBuffers(device, &allocInfo, &commandBuffer);

    VkCommandBufferBeginInfo beginInfo{};
    beginInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
    beginInfo.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;

    vkBeginCommandBuffer(commandBuffer, &beginInfo);

    VkImageMemoryBarrier barrier{};
    barrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
    barrier.oldLayout = oldLayout;
    barrier.newLayout = newLayout;
    barrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
    barrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
    barrier.image = image;
    barrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    barrier.subresourceRange.baseMipLevel = 0;
    barrier.subresourceRange.levelCount = mipLevels;
    barrier.subresourceRange.baseArrayLayer = 0;
    barrier.subresourceRange.layerCount = 1;

    VkPipelineStageFlags sourceStage;
    VkPipelineStageFlags destinationStage;

    if (oldLayout == VK_IMAGE_LAYOUT_UNDEFINED && newLayout == VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL) {
        barrier.srcAccessMask = 0;
        barrier.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;

        sourceStage = VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
        destinationStage = VK_PIPELINE_STAGE_TRANSFER_BIT;
    }
    else if (oldLayout == VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL && newLayout == VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL) {
        barrier.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
        barrier.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;

        sourceStage = VK_PIPELINE_STAGE_TRANSFER_BIT;
        destinationStage = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT;
    }
    else {
        throw std::invalid_argument("Unsupported layout transition!");
    }

    vkCmdPipelineBarrier(
        commandBuffer,
        sourceStage, destinationStage,
        0,
        0, nullptr,
        0, nullptr,
        1, &barrier
    );

    // End command buffer recording
    vkEndCommandBuffer(commandBuffer);

    // Submit command buffer
    VkSubmitInfo submitInfo{};
    submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
    submitInfo.commandBufferCount = 1;
    submitInfo.pCommandBuffers = &commandBuffer;

    vkQueueSubmit(graphicsQueue, 1, &submitInfo, VK_NULL_HANDLE);
    vkQueueWaitIdle(graphicsQueue);

    // Free command buffer
    vkFreeCommandBuffers(device, commandPool, 1, &commandBuffer);
}

void Texture::CreateImageView(VkFormat format, VkImageAspectFlags aspectFlags, uint32_t mipLevels)
{
    VkImageViewCreateInfo viewInfo{};
    viewInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
    viewInfo.image = image;
    viewInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
    viewInfo.format = format;
    viewInfo.subresourceRange.aspectMask = aspectFlags;
    viewInfo.subresourceRange.baseMipLevel = 0;
    viewInfo.subresourceRange.levelCount = mipLevels;
    viewInfo.subresourceRange.baseArrayLayer = 0;
    viewInfo.subresourceRange.layerCount = 1;

    if (vkCreateImageView(device, &viewInfo, nullptr, &imageView) != VK_SUCCESS)
    {
        throw std::runtime_error("Failed to create texture image view!");
    }
}

void Texture::CreateSampler(uint32_t mipLevels)
{
    VkSamplerCreateInfo samplerInfo{};
    samplerInfo.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
    samplerInfo.magFilter = VK_FILTER_LINEAR;
    samplerInfo.minFilter = VK_FILTER_LINEAR;
    samplerInfo.addressModeU = VK_SAMPLER_ADDRESS_MODE_REPEAT;
    samplerInfo.addressModeV = VK_SAMPLER_ADDRESS_MODE_REPEAT;
    samplerInfo.addressModeW = VK_SAMPLER_ADDRESS_MODE_REPEAT;
    samplerInfo.anisotropyEnable = VK_TRUE;
    samplerInfo.maxAnisotropy = 16;
    samplerInfo.borderColor = VK_BORDER_COLOR_INT_OPAQUE_BLACK;
    samplerInfo.unnormalizedCoordinates = VK_FALSE;
    samplerInfo.compareEnable = VK_FALSE;
    samplerInfo.compareOp = VK_COMPARE_OP_ALWAYS;
    samplerInfo.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
    samplerInfo.mipLodBias = 0.0f;
    samplerInfo.minLod = 0.0f;
    samplerInfo.maxLod = static_cast<float>(mipLevels);

    if (vkCreateSampler(device, &samplerInfo, nullptr, &sampler) != VK_SUCCESS)
    {
        throw std::runtime_error("Failed to create texture sampler!");
    }
}

void Texture::CopyBufferToImage(VkBuffer buffer, uint32_t width, uint32_t height)
{
    // Create a one-time-use command buffer
    VkCommandBufferAllocateInfo allocInfo{};
    allocInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
    allocInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
    allocInfo.commandPool = commandPool;
    allocInfo.commandBufferCount = 1;

    VkCommandBuffer commandBuffer;
    vkAllocateCommandBuffers(device, &allocInfo, &commandBuffer);

    VkCommandBufferBeginInfo beginInfo{};
    beginInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
    beginInfo.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;

    // Record buffer to image copy command in the command buffer
    vkBeginCommandBuffer(commandBuffer, &beginInfo);

    VkBufferImageCopy region{};
    region.bufferOffset = 0;
    region.bufferRowLength = 0;
    region.bufferImageHeight = 0;
    region.imageSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    region.imageSubresource.mipLevel = 0;
    region.imageSubresource.baseArrayLayer = 0;
    region.imageSubresource.layerCount = 1;
    region.imageOffset = { 0, 0, 0 };
    region.imageExtent = {
        width,
        height,
        1
    };

    vkCmdCopyBufferToImage(
        commandBuffer,
        buffer,
        image,
        VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
        1,
        &region
    );

    // End command buffer recording
    vkEndCommandBuffer(commandBuffer);

    // Submit command buffer
    VkSubmitInfo submitInfo{};
    submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
    submitInfo.commandBufferCount = 1;
    submitInfo.pCommandBuffers = &commandBuffer;

    vkQueueSubmit(graphicsQueue, 1, &submitInfo, VK_NULL_HANDLE);
    vkQueueWaitIdle(graphicsQueue);

    // Free command buffer
    vkFreeCommandBuffers(device, commandPool, 1, &commandBuffer);
}

BufferUtils.h:

#pragma once

#include <vulkan/vulkan.h>
#include <stdint.h>

namespace BufferUtils
{
    void CreateBuffer(
        VkDevice device, VkPhysicalDevice physicalDevice,
        VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags properties,
        VkBuffer& buffer, VkDeviceMemory& bufferMemory);

    uint32_t FindMemoryType(VkPhysicalDevice physicalDevice, uint32_t typeFilter, VkMemoryPropertyFlags properties);

    void CopyBuffer(
        VkDevice device, VkCommandPool commandPool, VkQueue graphicsQueue,
        VkBuffer srcBuffer, VkBuffer dstBuffer, VkDeviceSize size);
}

I am getting this error:

VUID-VkWriteDescriptorSet-descriptorType-00319(ERROR / SPEC): msgNum: -405619238 - Validation Error: [ VUID-VkWriteDescriptorSet-descriptorType-00319 ] Object 0: handle = 0xb097c90000000027, type = VK_OBJECT_TYPE_DESCRIPTOR_SET; | MessageID = 0xe7d2bdda | vkUpdateDescriptorSets() pDescriptorWrites[0] failed write update validation for VkDescriptorSet 0xb097c90000000027[] with error: Attempting write update to VkDescriptorSet 0xb097c90000000027[] allocated with VkDescriptorSetLayout 0xdd3a8a0000000015[] binding #0 with type VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER but update type is VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER. The Vulkan spec states: descriptorType must match the type of dstBinding within dstSet (https://vulkan.lunarg.com/doc/view/1.3.239.0/windows/1.3-extensions/vkspec.html#VUID-VkWriteDescriptorSet-descriptorType-00319)
    Objects: 1
        [0] 0xb097c90000000027, type: 23, name: NULL

It seems to occur when calling vkUpdateDescriptorSets in the Material::UpdateBufferBinding method. 

Here is some additional code from the Renderer class for context:

VkDescriptorSetLayout Renderer::CreateDescriptorSetLayout() {
	VkDescriptorSetLayoutBinding uboLayoutBinding{};
	uboLayoutBinding.binding = 0;
	uboLayoutBinding.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
	uboLayoutBinding.descriptorCount = 1;
	uboLayoutBinding.stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
	uboLayoutBinding.pImmutableSamplers = nullptr;

	// Add sampler layout binding
	VkDescriptorSetLayoutBinding samplerLayoutBinding{};
	samplerLayoutBinding.binding = 1;
	samplerLayoutBinding.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
	samplerLayoutBinding.descriptorCount = 1;
	samplerLayoutBinding.stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
	samplerLayoutBinding.pImmutableSamplers = nullptr;

	std::array<VkDescriptorSetLayoutBinding, 2> bindings = { uboLayoutBinding, samplerLayoutBinding };

	VkDescriptorSetLayoutCreateInfo layoutInfo{};
	layoutInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
	layoutInfo.bindingCount = static_cast<uint32_t>(bindings.size());
	layoutInfo.pBindings = bindings.data();

	VkDescriptorSetLayout descriptorSetLayout;
	if (vkCreateDescriptorSetLayout(device, &layoutInfo, nullptr, &descriptorSetLayout) != VK_SUCCESS) {
		throw std::runtime_error("Failed to create descriptor set layout!");
	}

	return descriptorSetLayout;
}

VkDescriptorSetLayout Renderer::CreateSamplerDescriptorSetLayout() {
	VkDescriptorSetLayoutBinding samplerLayoutBinding{};
	samplerLayoutBinding.binding = 0;
	samplerLayoutBinding.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
	samplerLayoutBinding.descriptorCount = 1;
	samplerLayoutBinding.stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
	samplerLayoutBinding.pImmutableSamplers = nullptr;

	VkDescriptorSetLayoutCreateInfo layoutInfo{};
	layoutInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
	layoutInfo.bindingCount = 1;
	layoutInfo.pBindings = &samplerLayoutBinding;

	VkDescriptorSetLayout descriptorSetLayout;
	if (vkCreateDescriptorSetLayout(device, &layoutInfo, nullptr, &descriptorSetLayout) != VK_SUCCESS) {
		throw std::runtime_error("Failed to create sampler descriptor set layout!");
	}

	return descriptorSetLayout;
}

VkDescriptorPool Renderer::CreateDescriptorPool(uint32_t maxSets) {
	VkDescriptorPoolSize poolSize{};
	poolSize.type = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
	poolSize.descriptorCount = maxSets;

	// Add an additional descriptor pool size for COMBINED_IMAGE_SAMPLER
	VkDescriptorPoolSize samplerPoolSize{};
	samplerPoolSize.type = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
	samplerPoolSize.descriptorCount = maxSets;

	std::array<VkDescriptorPoolSize, 2> poolSizes = { poolSize, samplerPoolSize };

	VkDescriptorPoolCreateInfo poolInfo{};
	poolInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
	poolInfo.poolSizeCount = static_cast<uint32_t>(poolSizes.size());
	poolInfo.pPoolSizes = poolSizes.data();
	poolInfo.maxSets = maxSets;

	VkDescriptorPool descriptorPool;
	if (vkCreateDescriptorPool(device, &poolInfo, nullptr, &descriptorPool) != VK_SUCCESS) {
		throw std::runtime_error("Failed to create descriptor pool!");
	}

	return descriptorPool;
}

How can I alter the code to fix this issue?