Karma::FVulkanDynamicRHI Class Reference

Vulkan implementation of the Dynamic RHI. More...

#include <VulkanDynamicRHI.h>

Inheritance diagram for Karma::FVulkanDynamicRHI:

Public Member Functions
	FVulkanDynamicRHI ()
	Initialization constructor.
virtual bool	Init () override
	For initializing VulkanDynamic RHI.
virtual void	Shutdown () override
	Shuts down the RHI.
void	InitInstance ()
	Calls FVulkanDevice::InitGPU() to create Vulkan logical device from selected GPU, and created appropriate resources (commandpool, default texture etc).
virtual void	Present () override
	Presents the rendered frame to the display.
SwapChainSupportDetails	QuerySwapChainSupport (VkPhysicalDevice device)
	Uses Two-Pass Query to gather surface formats (physical device and surface paired color space or pixel format data) and present modes data.
VkInstance	GetInstance () const
	Getter for Vulkan instance.
FVulkanDevice *	GetDevice () const
	Getter for FVulkanDevice object created in FVulkanDynamicRHI::SelectDevice().
QueueFamilyIndices	FindQueueFamilies (VkPhysicalDevice device)
	Queries the graphics card for available queue families and compares against the availability of graphics and presentation queues.
bool	GetValidationLayersSetting () const
	Getter for the boolean bEnableValidationLayers.
const VkPhysicalDeviceFeatures &	GetGpuDeviceFeatures () const
	Getter for m_SupportedDeviceFeatures which contains boolean values for supported features like availability of geometry shader or sampler anisotropy.
const SwapChainSupportDetails &	GetGpuSwapChainSupportDetails () const
	Getter for m_GPUSwapChainSupport struct which gets initialized in FVulkanDynamicRHI::IsDeviceSuitable().
uint32_t	SwapChainImageCount () const
	Getter for the number of supported swapchain images.
VkFormat	FindSupportedFormat (const std::vector< VkFormat > &candidates, VkImageTiling tiling, VkFormatFeatureFlags features) const
	Finds a supported format from the list of candidate formats based on the desired tiling and features. Used in depth resource creation.
VkFormat	FindDepthFormat () const
	Finds an appropriate depth format for depth resources.
uint32_t	FindMemoryType (uint32_t typeFilter, VkMemoryPropertyFlags properties)
	Finds appropriate memory type with demanded properties. Basically a loop is run from counter i = 0 to VkPhysicalDeviceMemoryProperties.memoryTypeCount (number of valid elements in the memoryTypes array) and memoryType[i] is queried for appropriate properties. On condition satisfaction, counter i is returned.
void	RegisterUniformBufferObject (VulkanUniformBuffer *ubo)
	Register a uniformbuffer object to curate an array or uniformbuffers.
void	UploadUniformBufferObjects (size_t frameIndex)
	Uploads data to the registered VulkanUniformBuffers for the specified frame index.
GLFWwindow *	GetSurfaceWindow () const
VkSurfaceKHR	GetSurface () const
Public Member Functions inherited from Karma::IVulkanDynamicRHI
virtual ERHIInterfaceType	GetInterfaceType () const override
Public Member Functions inherited from Karma::FDynamicRHI
virtual	~FDynamicRHI ()=default
	Virtual destructor for FDynamicRHI.

Static Public Member Functions
static FVulkanDynamicRHI &	Get ()
	Getter for the FVulkanDynamicRHI instance.
Static Public Member Functions inherited from Karma::FDynamicRHI
static FDynamicRHI *	CreateRHI ()

Static Public Attributes
static std::vector< const char * >	deviceExtensions = { VK_KHR_SWAPCHAIN_EXTENSION_NAME }
static const std::vector< const char * >	validationLayers = {"VK_LAYER_KHRONOS_validation"}

Protected Member Functions
void	CreateInstance ()
	Creates a Vulkan instance.
void	SetupDebugMessenger ()
	Sets up the debug messenger for Vulkan instance.
void	CreateSurface ()
	Platform agnostic creation of surface to present rendered images to. Typically they are backed by the category of glfw windows (on Linux, MacOS, and Windows).
void	SelectDevice ()
	Picks an Engine appropriate GPU and creates FVulkanDevice.

Protected Attributes
uint32_t	m_APIVersion
VkInstance	m_VulkanInstance
FVulkanDevice *	m_Device
VkDebugUtilsMessengerEXT	m_DebugMessenger
GLFWwindow *	m_WindowHandle
VkSurfaceKHR	m_Surface
VkPhysicalDeviceFeatures	m_SupportedDeviceFeatures
VkPhysicalDevice	m_PhysicalDevice = VK_NULL_HANDLE
SwapChainSupportDetails	m_GPUSwapChainSupport
uint32_t	m_SwapChainImageCount
std::set< VulkanUniformBuffer * >	m_VulkanUBO

Static Protected Attributes
static bool	bEnableValidationLayers = false

Detailed Description

Vulkan implementation of the Dynamic RHI.

Provides Vulkan-specific implementations for initializing/deinitializing RHI along with Vulkan resources and rendering operations.

Since

Karma 1.0.0

Constructor & Destructor Documentation

FVulkanDynamicRHI()

Karma::FVulkanDynamicRHI::FVulkanDynamicRHI

(

)

Initialization constructor.

Does the following

1. Creates vkInstance
2. Sets up debug messenger (with Karma's logging callback function)
3. Creates a Vulkan surface to interface with the Engine's window (Editor window for instance)
4. Selects a physical device (GPU) based upon the availability of device extensions, swapchain support, and samplerAnisotropy
5. Creates Vulkan logical device

Note

Smapler anisotorpy is a technique that makes textures on surfaces viewed at steep angles (like roads or floors stretching into the distance) look clearer and sharper, preventing blurriness by taking multiple samples along the texture's axis of elongation rather than a single one.

Since

Karma 1.0.0

Member Function Documentation

CreateInstance()

void Karma::FVulkanDynamicRHI::CreateInstance ( )

protected

Creates a Vulkan instance.

Since

Karma 1.0.0

CreateSurface()

void Karma::FVulkanDynamicRHI::CreateSurface ( )

protected

Platform agnostic creation of surface to present rendered images to. Typically they are backed by the category of glfw windows (on Linux, MacOS, and Windows).

Since

Karma 1.0.0

FindDepthFormat()

VkFormat Karma::FVulkanDynamicRHI::FindDepthFormat

(

)

const

Finds an appropriate depth format for depth resources.

See also

KarmaGuiVulkanHandler::MakeRenderPassInfo

Since

Karma 1.0.0

FindMemoryType()

uint32_t Karma::FVulkanDynamicRHI::FindMemoryType	(	uint32_t	typeFilter,
		VkMemoryPropertyFlags	properties )

Finds appropriate memory type with demanded properties. Basically a loop is run from counter i = 0 to VkPhysicalDeviceMemoryProperties.memoryTypeCount (number of valid elements in the memoryTypes array) and memoryType[i] is queried for appropriate properties. On condition satisfaction, counter i is returned.

Graphics cards can offer different types of memory to allocate from. Each type of memory varies in terms of allowed operations and performance characteristics. We need to combine the requirements of the buffer and our own application requirements to find the right type of memory to use.

Parameters

typeFilter	A bitmask, and contains one bit set for every supported memory type for the resource. Bit i is set if and only if the memory type i in the VkPhysicalDeviceMemoryProperties structure for the physical device is supported for the resource.
properties	The demanded properties (https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VkBufferUsageFlagBits.html).

Returns

Memory type index i

See also

VulkanUniformBuffer::CreateBuffer

Since

Karma 1.0.0

FindQueueFamilies()

QueueFamilyIndices Karma::FVulkanDynamicRHI::FindQueueFamilies

(

VkPhysicalDevice

device

)

Queries the graphics card for available queue families and compares against the availability of graphics and presentation queues.

Parameters

device

The graphics card to be queired for queue family

Since

Karma 1.0.0

FindSupportedFormat()

VkFormat Karma::FVulkanDynamicRHI::FindSupportedFormat	(	const std::vector< VkFormat > &	candidates,
		VkImageTiling	tiling,
		VkFormatFeatureFlags	features ) const

Finds a supported format from the list of candidate formats based on the desired tiling and features. Used in depth resource creation.

See also

KarmaGuiVulkanHandler::MakeRenderPassInfo

Since

Karma 1.0.0

Get()

FVulkanDynamicRHI & Karma::FVulkanDynamicRHI::Get ( )

inlinestatic

Getter for the FVulkanDynamicRHI instance.

Since

Karma 1.0.0

GetDevice()

FVulkanDevice * Karma::FVulkanDynamicRHI::GetDevice ( ) const

inline

Getter for FVulkanDevice object created in FVulkanDynamicRHI::SelectDevice().

Since

Karma 1.0.0

GetGpuDeviceFeatures()

const VkPhysicalDeviceFeatures & Karma::FVulkanDynamicRHI::GetGpuDeviceFeatures ( ) const

inline

Getter for m_SupportedDeviceFeatures which contains boolean values for supported features like availability of geometry shader or sampler anisotropy.

Since

Karma 1.0.0

GetGpuSwapChainSupportDetails()

const SwapChainSupportDetails & Karma::FVulkanDynamicRHI::GetGpuSwapChainSupportDetails ( ) const

inline

Getter for m_GPUSwapChainSupport struct which gets initialized in FVulkanDynamicRHI::IsDeviceSuitable().

Since

Karma 1.0.0

GetInstance()

VkInstance Karma::FVulkanDynamicRHI::GetInstance ( ) const

inline

Getter for Vulkan instance.

Since

Karma 1.0.0

GetValidationLayersSetting()

bool Karma::FVulkanDynamicRHI::GetValidationLayersSetting ( ) const

inline

Getter for the boolean bEnableValidationLayers.

For Debug builds bEnableValidationLayers is set to true

Since

Karma 1.0.0

Init()

bool Karma::FVulkanDynamicRHI::Init ( )

overridevirtual

For initializing VulkanDynamic RHI.

Called from RHIInit() declared in KarmaRHI.h and defined in DynamicRHI.cpp

See also

FVulkanDynamicRHI::InitInstance()

Since

Karma 1.0.0

Implements Karma::FDynamicRHI.

InitInstance()

void Karma::FVulkanDynamicRHI::InitInstance

(

)

Calls FVulkanDevice::InitGPU() to create Vulkan logical device from selected GPU, and created appropriate resources (commandpool, default texture etc).

See also

FVulkanDevice::InitGPU()

Since

Karma 1.0.0

Present()

virtual void Karma::FVulkanDynamicRHI::Present ( )

inlineoverridevirtual

Presents the rendered frame to the display.

Since

Karma 1.0.0

Implements Karma::FDynamicRHI.

QuerySwapChainSupport()

SwapChainSupportDetails Karma::FVulkanDynamicRHI::QuerySwapChainSupport

(

VkPhysicalDevice

device

)

Uses Two-Pass Query to gather surface formats (physical device and surface paired color space or pixel format data) and present modes data.

See also

VulkanContext::IsDeviceSuitable(), and VulkanContext::CreateSwapChain()

Since

Karma 1.0.0

RegisterUniformBufferObject()

void Karma::FVulkanDynamicRHI::RegisterUniformBufferObject

(

VulkanUniformBuffer *

ubo

)

Register a uniformbuffer object to curate an array or uniformbuffers.

Note

May be abstracted to FDynamicRHI.

In Unreal Engine, there is no single global “array of uniform buffers” that UpdateUniformBuffer walks; instead, each system owns its own uniform buffer(s) and explicitly passes them into UpdateUniformBuffer when something changes. Where the inputs come from Uniform buffers are created and owned by higher-level engine systems: Per-primitive: via FPrimitiveSceneInfo for object transforms, lighting, etc. Per-view / per-pass: view uniforms, fog, shadow parameters, etc. Per-material: FMaterialParameterCollectionInstance and other material parameter structs.

SelectDevice()

void Karma::FVulkanDynamicRHI::SelectDevice ( )

protected

Picks an Engine appropriate GPU and creates FVulkanDevice.

Since

Karma 1.0.0

SetupDebugMessenger()

void Karma::FVulkanDynamicRHI::SetupDebugMessenger ( )

protected

Sets up the debug messenger for Vulkan instance.

This function initializes the debug messenger that will handle debug messages from the Vulkan API. It populates the debug messenger create info structure and creates the debug messenger using the CreateDebugUtilsMessengerEXT function.

See also

FVulkanDynamicRHI::CreateDebugUtilsMessengerEXT()

Since

Karma 1.0.0

Shutdown()

void Karma::FVulkanDynamicRHI::Shutdown ( )

overridevirtual

Shuts down the RHI.

Called from RHIExit() declared in KarmaRHI.h and defined in DynamicRHI.cpp

Cleans up resources and states used by the RHI.

Since

Karma 1.0.0

Implements Karma::FDynamicRHI.

SwapChainImageCount()

uint32_t Karma::FVulkanDynamicRHI::SwapChainImageCount ( ) const

inline

Getter for the number of supported swapchain images.

Since

Karma 1.0.0

UploadUniformBufferObjects()

void Karma::FVulkanDynamicRHI::UploadUniformBufferObjects

(

size_t

frameIndex

)

Uploads data to the registered VulkanUniformBuffers for the specified frame index.

Typically called during rendering to update uniform buffer data for the current frame like so

vkCmdBeginRenderPass
 vkCmdBindPipeline
 vkCmdBindVertexBuffers
 vkCmdBindIndexBuffer
 UploadUniformBufferObjects()
 vkCmdBindDescriptorSets // Descriptor sets include UBOs
 vkCmdDrawIndexed
vkCmdEndRenderPass

Parameters

frameIndex

The index of the frame for which to upload UBO data

Note

The frameIndex is used to determine which uniform buffer to update, as multiple buffers may be used for double or triple buffering to avoid synchronization issues between CPU and GPU.

The uniform buffers are resized automatically based on MAX_FRAMES_IN_FLIGHT (number of images (to work upon (CPU side) whilst an image is being rendered (GPU side processing)) + 1)

See also

VulkanUniformBuffer::BufferCreation()

KarmaGuiRenderer::FrameRender, VulkanBuffer::UploadUniformBuffer

Since

Karma 1.0.0

---

The documentation for this class was generated from the following files:

• Karma/src/Platform/Vulkan/VulkanRHI/VulkanDynamicRHI.h
• Karma/src/Platform/Vulkan/VulkanRHI/VulkanRHI.cpp