Vulkan Cookbook

By : Pawel Lapinski

Vulkan Cookbook

By: Pawel Lapinski

Overview of this book

Vulkan is the next generation graphics API released by the Khronos group. It is expected to be the successor to OpenGL and OpenGL ES, which it shares some similarities with such as its cross-platform capabilities, programmed pipeline stages, or nomenclature. Vulkan is a low-level API that gives developers much more control over the hardware, but also adds new responsibilities such as explicit memory and resources management. With it, though, Vulkan is expected to be much faster. This book is your guide to understanding Vulkan through a series of recipes. We start off by teaching you how to create instances in Vulkan and choose the device on which operations will be performed. You will then explore more complex topics such as command buffers, resources and memory management, pipelines, GLSL shaders, render passes, and more. Gradually, the book moves on to teach you advanced rendering techniques, how to draw 3D scenes, and how to improve the performance of your applications. By the end of the book, you will be familiar with the latest advanced techniques implemented with the Vulkan API, which can be used on a wide range of platforms.

Preface

What this book covers

What you need for this book

Free Chapter

Instance and Devices

Introduction

Downloading Vulkan's SDK

Enabling validation layers

Connecting with a Vulkan Loader library

Preparing for loading Vulkan API functions

Loading functions exported from a Vulkan Loader library

Loading global-level functions

Checking available Instance extensions

Creating a Vulkan Instance

Loading instance-level functions

Enumerating available physical devices

Checking available device extensions

Getting features and properties of a physical device

Checking available queue families and their properties

Selecting the index of a queue family with the desired capabilities

Creating a logical device

Loading device-level functions

Getting a device queue

Creating a logical device with geometry shaders, graphics, and compute queues

Destroying a logical device

Destroying a Vulkan Instance

Releasing a Vulkan Loader library

Image Presentation

Introduction

Creating a Vulkan Instance with WSI extensions enabled

Creating a presentation surface

Selecting a queue family that supports presentation to a given surface

Creating a logical device with WSI extensions enabled

Selecting a desired presentation mode

Getting the capabilities of a presentation surface

Selecting a number of swapchain images

Choosing a size of swapchain images

Selecting desired usage scenarios of swapchain images

Selecting a transformation of swapchain images

Selecting a format of swapchain images

Creating a swapchain

Getting handles of swapchain images

Creating a swapchain with R8G8B8A8 format and a mailbox present mode

Acquiring a swapchain image

Presenting an image

Destroying a swapchain

Destroying a presentation surface

Command Buffers and Synchronization

Introduction

Creating a command pool

Allocating command buffers

Beginning a command buffer recording operation

Ending a command buffer recording operation

Resetting a command buffer

Resetting a command pool

Submitting command buffers to a queue

Synchronizing two command buffers

Checking if processing of a submitted command buffer has finished

Waiting until all commands submitted to a queue are finished

Waiting for all submitted commands to be finished

Destroying a fence

Destroying a semaphore

Freeing command buffers

Destroying a command pool

Resources and Memory

Introduction

Creating a buffer

Allocating and binding a memory object for a buffer

Setting a buffer memory barrier

Creating a buffer view

Creating an image

Allocating and binding a memory object to an image

Setting an image memory barrier

Creating an image view

Creating a 2D image and view

Creating a layered 2D image with a CUBEMAP view

Mapping, updating and unmapping host-visible memory

Copying data between buffers

Copying data from a buffer to an image

Copying data from an image to a buffer

Using a staging buffer to update a buffer with a device-local memory bound

Using a staging buffer to update an image with a device-local memory bound

Destroying an image view

Destroying an image

Destroying a buffer view

Freeing a memory object

Destroying a buffer

Descriptor Sets

Introduction

Creating a sampler

Creating a sampled image

Creating a combined image sampler

Creating a storage image

Creating a uniform texel buffer

Creating a storage texel buffer

Creating a uniform buffer

Creating a storage buffer

Creating an input attachment

Creating a descriptor set layout

Creating a descriptor pool

Allocating descriptor sets

Updating descriptor sets

Binding descriptor sets

Creating descriptors with a texture and a uniform buffer

Freeing descriptor sets

Resetting a descriptor pool

Destroying a descriptor pool

Destroying a descriptor set layout

Destroying a sampler

Render Passes and Framebuffers

Introduction

Specifying attachments descriptions

Specifying subpass descriptions

Specifying dependencies between subpasses

Creating a render pass

Creating a framebuffer

Preparing a render pass for geometry rendering and postprocess subpasses

Preparing a render pass and a framebuffer with color and depth attachments

Beginning a render pass

Progressing to the next subpass

Ending a render pass

Destroying a framebuffer

Destroying a render pass

Shaders

Introduction

Converting GLSL shaders to SPIR-V assemblies

Writing vertex shaders

Writing tessellation control shaders

Writing tessellation evaluation shaders

Writing geometry shaders

Writing fragment shaders

Writing compute shaders

Writing a vertex shader that multiplies vertex position by a projection matrix

Using push constants in shaders

Writing texturing vertex and fragment shaders

Displaying polygon normals with a geometry shader

Graphics and Compute Pipelines

Introduction

Creating a shader module

Specifying pipeline shader stages

Specifying a pipeline vertex binding description, attribute description, and input state

Specifying a pipeline input assembly state

Specifying a pipeline tessellation state

Specifying a pipeline viewport and scissor test state

Specifying a pipeline rasterization state

Specifying a pipeline multisample state

Specifying a pipeline depth and stencil state

Specifying a pipeline blend state

Specifying pipeline dynamic states

Creating a pipeline layout

Specifying graphics pipeline creation parameters

Creating a pipeline cache object

Retrieving data from a pipeline cache

Merging multiple pipeline cache objects

Creating a graphics pipeline

Creating a compute pipeline

Binding a pipeline object

Creating a pipeline layout with a combined image sampler, a buffer, and push constant ranges

Creating a graphics pipeline with vertex and fragment shaders, depth test enabled, and with dynamic viewport and scissor tests

Creating multiple graphics pipelines on multiple threads

Destroying a pipeline

Destroying a pipeline cache

Destroying a pipeline layout

Destroying a shader module

Command Recording and Drawing

Introduction

Clearing a color image

Clearing a depth-stencil image

Clearing render pass attachments

Binding vertex buffers

Binding an index buffer

Providing data to shaders through push constants

Setting viewport states dynamically

Setting scissor states dynamically

Setting line width states dynamically

Setting depth bias states dynamically

Setting blend constants states dynamically

Drawing a geometry

Drawing an indexed geometry

Dispatching compute work

Executing a secondary command buffer inside a primary command buffer

Recording a command buffer that draws a geometry with dynamic viewport and scissor states

Recording command buffers on multiple threads

Preparing a single frame of animation

Increasing the performance through increasing the number of separately rendered frames

Helper Recipes

Introduction

Preparing a translation matrix

Preparing a rotation matrix

Preparing a scaling matrix

Preparing a perspective projection matrix

Preparing an orthographic projection matrix

Loading texture data from a file

Loading a 3D model from an OBJ file

Lighting

Introduction

Rendering a geometry with a vertex diffuse lighting

Rendering a geometry with a fragment specular lighting

Rendering a normal mapped geometry

Drawing a reflective and refractive geometry using cubemaps

Adding shadows to the scene

Advanced Rendering Techniques

Introduction

Drawing a skybox

Drawing billboards using geometry shaders

Drawing particles using compute and graphics pipelines

Rendering a tessellated terrain

Rendering a full-screen quad for post-processing

Using input attachments for a color correction post-process effect

Customer Reviews

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Enabling validation layers

The Vulkan API was designed with performance in mind. One way to increase its performance is to lower state and error checking performed by the driver. This is one of the reasons Vulkan is called a "thin API" or "thin driver," it is a minimal abstraction of the hardware, which is required for the API to be portable across multiple hardware vendors and device types (high-performance desktop computers, mobile phones, and integrated and low-power embedded systems).

However, this approach makes creating applications with the Vulkan API much more difficult, compared to the traditional high-level APIs such as OpenGL. It's because very little feedback is given to developers by the driver, as it expects that programmers will correctly use the API and abide by rules defined in the Vulkan specification.

To mitigate this problem, Vulkan was also designed to be a layered API. The lowest layer, the core, is the Vulkan API itself, which communicates with the Driver, allowing us to program the Hardware (as seen in the preceding diagram). On top of it (between the Application and the Vulkan API), developers can enable additional layers, to ease the debugging process.

How to do it...

On the Windows operating system family:

Go to the folder in which the SDK was installed and then open the Config sub-directory.
Copy the vk_layer_settings.txt file into the directory of the executable you want to debug (into a folder of an application you want to execute).
Create an environment variable named VK_INSTANCE_LAYERS:
1. Open the command-line console (Command Prompt/cmd.exe).
2. Type the following:

              setx VK_INSTANCE_LAYERS 
              VK_LAYER_LUNARG_standard_validation

3. Close the console.

Re-open the command prompt once again.
Change the current directory to the folder of the application you want to execute.
Run the application; potential warnings or errors will be displayed in the standard output of the command prompt.

On the Linux operating system family:

Go to the folder in which the SDK was installed and then open the Config sub-directory.
Copy the vk_layer_settings.txt file into the directory of the executable you want to debug (into a folder of an application you want to execute).
Create an environment variable named VK_INSTANCE_LAYERS:
1. Open the Terminal window.
2. Type the following:

              export
              VK_INSTANCE_LAYERS=VK_LAYER_LUNARG_standard_validation

Run the application; potential warnings or errors will be displayed in the standard output of the Terminal window.

How it works...

Vulkan validation layers contain a set of libraries which help find potential problems in created applications. Their debugging capabilities include, but are not limited to, validating parameters passed to Vulkan functions, validating texture and render target formats, tracking Vulkan objects and their lifetime and usage, and checking for potential memory leaks or dumping (displaying/printing) Vulkan API function calls. These functionalities are enabled by different validation layers, but most of them are gathered into a single layer called VK_LAYER_LUNARG_standard_validation which is enabled in this recipe. Examples of names of other layers include VK_LAYER_LUNARG_swapchain, VK_LAYER_LUNARG_object_tracker, VK_LAYER_GOOGLE_threading, or VK_LAYER_LUNARG_api_dump, among others. Multiple layers can be enabled at the same time, in a similar way as presented here in the recipe. Just assign the names of the layers you want to activate to the VK_INSTANCE_LAYERS environment variable. If you are a Windows OS user, remember to separate them with a semicolon, as in the example:

setx VK_INSTANCE_LAYERS VK_LAYER_LUNARG_api_dump;VK_LAYER_LUNARG_core_validation

If you are a Linux OS user, separate them with a colon. Here is an example:

export VK_INSTANCE_LAYERS=VK_LAYER_LUNARG_api_dump:VK_LAYER_LUNARG _core_validation

The environment variable named VK_INSTANCE_LAYERS can be also set with other OS specific ways such as, advanced operating system settings on Windows or /etc/environment on Linux.

The preceding examples enable validation layers globally, for all applications, but they can also be enabled only for our own application, in its source code during Instance creation. However, this approach requires us to recompile the whole program every time we want to enable or disable different layers. So, it is easier to enable them using the preceding recipe. This way, we also won't forget to disable them when we want to ship the final version of our application. To disable validation layers, we just have to delete VK_INSTANCE_LAYERS environment variable.

Validation layers should not be enabled in the released (shipped) version of the applications as they may drastically decrease performance.

For a full list of available validation layers, please refer to the documentation, which can be found in the Documentation sub-folder of the directory in which the Vulkan SDK was installed.

Vulkan Cookbook

By : Pawel Lapinski

Vulkan Cookbook

By: Pawel Lapinski

Overview of this book

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