PyVK

Python bindings for the Vulkan C libraries.

This consists of two parts.

1. The C - Extension which exposes the Vulkan structures and functions to Python.
2. A python file which defines the enums, provided wrapper classes around the C-extension classes, does value checking on the inputs to the classes and is imported by the client scripts.

C - Extension

This is a CPython extension. Vulkan structures are provided as classes and their members as class attributes.

Structures which have members like the following

VkStruct {
    ...

    VkAnotherStruct* anotherStructPtr;
    uint32_t anotherStructPtrCount;

    ...
}

are provided as a list in the python classes.

class Struct {
    anotherStruct = []
}

The C code can easily get the necessary data from list to pass to the raw Vulkan structure.

VkExtent2D and friends are to be passed as tuples. e.g. VkExtent2D will be passed as (width, height) etc.

Most functions are provided as part of classes they operate on.

e.g.

vkGetPhysicalDeviceSurfaceFormatsKHR(VkPhysicalDevice physicalDevice, VkSurfaceKHR surface, ...... );

//

vkCreateFence(VkDevice device, const VkFenceCreateInfo* pCreateInfo, ...... );

are provided as part of the PhysicalDevice class, and Device class respectively as

class PhysicalDevice(vk.physical_device):
    ...

    def get_surface_formatsi_khr(self, surface=vk.surface):
        ...

and

class Device(vk.device):
    ...

    def create_fence(self, fence_create_info=FenceCreateInfo):
        ...

Raw vulkan C functions which have an 'out' parameter, and return a VkResult, are implemented to return a tuple(out, Result) as seen below in the create_instance example.

Raw vulkan C functions which do not have an 'out' parameter, and return a VkResult, are implemented to return a result.

Raw vulkan C functions which do not have an 'out' parameter, and do not return a VkResult, are implemented to return None.

Python code

The enums are provided as class enums.

e.g.

typedef enum VkResult {
    VK_SUCCESS = 0,
    VK_NOT_READY = 1,
    
    ...

    VK_ERROR_OUT_OF_HOST_MEMORY = -1,
    VK_ERROR_OUT_OF_DEVICE_MEMORY = -2,
    ...

};

is provided as

class Result(Enum):
    SUCCESS = 0
    NOT_READY = 1

    ...

    ERROR_OUT_OF_HOST_MEMORY = -1
    ERROR_OUT_OF_DEVICE_MEMORY = -2

    ...

There are wrapper classes created for the **CreateInfo structures. These classes create the **CreateInfo objects which can be used in Python.

They provide acceptable default values. They do value checks when called by the client program and pass on the values to the C extension function.

There are wrapper classes created for objects that have functionality attached to them. e.g.

class Device(vk.device):
    ...

    def create_fence(self, fence_create_info=FenceCreateInfo):
        ...

The python code is imported into the client application via

from pyvk import pyvk as vk

and from there vulkan structs (classes in Python) are accessed by

app_info = vk.ApplicationInfo(p_next=None,
                              app_name="Chip8", app_ver=(1, 0, 0, 0), 
                              engine_ver=engine_ver, engine_name="Chip8")

instance_ci = vk.InstanceCreateInfo(p_next=None,
                                    flags=0, app_info=app_info,
                                    enabled_extensions=[
                                        vk.InstanceExtensionNames.KHR_SURFACE_EXTENSION_NAME,
                                        vk.InstanceExtensionNames.KHR_WIN32_SURFACE_EXTENSION_NAME
                                    ])
self.i, result = vk.create_instance(instance_ci)                                    

and the enums are accessed by

result = some_operation(...)

if result != vk.Result.SUCCESS:
    raise SystemError(f'Some operation did not succeed')

Please refer to my Chip8 Interpreter built using PySide6 for the GUI and pyvk for drawing.

Disclaimer

This extension/package only wraps around the vulkan class and functions that were required to get the Chip8 Interpreter working.

Current Implementation

Structures, functions and enums around the following operations have been implemented thus far.

1. Creating/destroying a Vulkan instance.
2. Getting physical devices. Getting device properties, memory properties.
3. Creating/destroying a surface.
4. Creating/destroying a logical device.
5. Creating/destroying a command pool.
6. Allocating/freeing command buffers.
7. Creating/destroying a swapchain.
8. Creating/destroying an image.
9. Creating/destroying an image view.
10. Beginning/ending command buffers.
11. Transitioning image layouts.
12. Issuing Image Copy, Image Blit operations.
13. Issuing Pipeline Barriers.
14. Queue Submissing and Presentation.

TO-DO:

1. Implement the setAttr and getAttr C extension function. For now the attributes in the classes can be set only by passing them to the init function.
2. The rest of the Vulkan API.

CONTRIBUTIONS

Awaiting your feedback, inputs, tips, pull requests on everything as this develops further.