Krust

Note that this is a work in progress library, not yet ready for users, and this github repo is maybe best viewed as off-site backup for the developer for now. Having noted that, in a layered graphics stack, Krust seeks to solve problems one level up from the explicit GPU API Vulkan. There are currently three modules:

• krust: The helpers for working with Vulkan. Functions to initialise most of the structures used in the Vulkan API can be found in krust/public-api/vulkan_struct_init.h. There is currently some reusable Vulkan helper code in krust/public-api/vulkan-utils.h. Classes implementing RAII for Vulkan API objects are being built in krust/public-api/vulkan-objects.h and krust/public-api/vulkan-objects.cpp.
• krust-io: A windowing and input library for Vulkan apps using core Krust. This allows very easily opening a window and starting writing Vulkan code on Windows or Linux. There is some reusable Vulkan code (subject to being rewritten and moved) in krust-io/internal/vulkan-helpers.h and Vulkan example code in krust-io/public-api/application.cpp
• krust-examples: Example Vulkan apps using krust-io and krust core.

Building

Use the --recurse-submodules when git cloneing the repository to pull in the third party dependencies. They can be retrieved later if the initial clone was not recursive. See BUILD.md in this directory for instructions.

*** Note: krust-io currently only builds for Linux and the example apps only run on Nvidia. ***

Using Krust

Struct Initializers

Vulkan has many structs to be passed into its API which are tagged with a long enumerant and have an extension void pointer which must always be set to null at present. The utility functions in krust/public-api/vulkan_struct_init.h make sure the enumerant always has the correct value and the extension pointer is null. There are variants which also ensure that every struct member is initialised and none are omitted. In addition there are initialisation functions for small structs used in the API.

Examples

Usage without the initialization functions:

 VkImageCreateInfo info;
 info.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
 info.pNext = nullptr;
 info.flags = 0;
 info.imageType = VK_IMAGE_TYPE_2D;
 // ...

Usage with the first set which only set the standard first two members:

 auto info = ImageCreateInfo();
 info.flags = 0;
 info.imageType = VK_IMAGE_TYPE_2D;
 // ...

In the second example those first two lines of member initialization are saved and the enum is guaranteed correct.

Usage with the second set of initialisers which take parameters and guarantee that all members are set:

 auto info = ImageCreateInfo(
   0,
   VK_IMAGE_TYPE_2D,
   // ...
 );

Initialising a simple struct without these helpers:

  VkOffset2D offset;
  offset.x = 64;
  offset.y = 128;

Usage with these helpers:

auto offset = Offset2D(64, 128)

See krust-examples/clear/clear.cpp and krust-examples/clear2/clear2.cpp for more usage examples.

Developing Krust

Coding Standard

See the design docs here.

Adding a Header File to Krust

To add a public header to the core Krust project, edit the CMakeLists.txt for it which lives at: krust/public-api/CMakeLists.txt.

set(KRUST_PUBLIC_API_HEADER_FILES
  ${KRUST_PUBLIC_API_DIR}/krust.h
  ${KRUST_PUBLIC_API_DIR}/vulkan_struct_init.h
  ${KRUST_PUBLIC_API_DIR}/new_file.h) //< Add your file here