**Documentation:** See [Vulkan Memory Allocator](https://gpuopen-librariesandsdks.github.io/VulkanMemoryAllocator/html/) (generated from Doxygen-style comments in [src/vk_mem_alloc.h](src/vk_mem_alloc.h))
Memory allocation and resource (buffer and image) creation in Vulkan is difficult (comparing to older graphics API-s, like D3D11 or OpenGL) for several reasons:
- It requires a lot of boilerplate code, just like everything else in Vulkan, because it is a low-level and high-performance API.
- There is additional level of indirection: `VkDeviceMemory` is allocated separately from creating `VkBuffer`/`VkImage` and they must be bound together. The binding cannot be changed later - resource must be recreated.
- Driver must be queried for supported memory heaps and memory types. Different IHVs provide different types of it.
- It is recommended practice to allocate bigger chunks of memory and assign parts of them to particular resources.
# Features
This library can help game developers to manage memory allocations and resource creation by offering some higher-level functions. Features of the library are divided into several layers, low level to high level:
1. Functions that help to choose correct and optimal memory type based on intended usage of the memory.
- Required or preferred traits of the memory are expressed using higher-level description comparing to Vulkan flags.
2. Functions that allocate memory blocks, reserve and return parts of them (`VkDeviceMemory` + offset + size) to the user.
- Library keeps track of allocated memory blocks, used and unused ranges inside them, finds best matching unused ranges for new allocations, takes all the rules of alignment and buffer/image granularity into consideration.
3. Functions that can create an image/buffer, allocate memory for it and bind them together - all in one call.
Additional features:
- Thread-safety: Library is designed to be used by multithreaded code.
- Configuration: Fill optional members of CreateInfo structure to provide custom CPU memory allocator and other parameters.
- Customization: Predefine appropriate macros to provide your own implementation of all external facilities used by the library, from assert, mutex, and atomic, to vector and linked list.
- Support for persistently mapped memory: Just allocate memory with appropriate flag and you get access to mapped pointer.
- Custom memory pools: Create a pool with desired parameters (e.g. fixed or limited maximum size) and allocate memory out of it.
- Defragmentation: Call one function and let the library move data around to free some memory blocks and make your allocations better compacted.
- Lost allocations: Allocate memory with appropriate flags and let the library remove allocations that are not used for many frames to make room for new ones.
- Statistics: Obtain detailed statistics about the amount of memory used, unused, number of allocated blocks, number of allocations etc. - globally, per memory heap, and per memory type.
- JSON dump: Obtain a string in JSON format with detailed map of internal state, including list of allocations and gaps between them.
# Prequisites
- Self-contained C++ library in single header file. No external dependencies other than standard C and C++ library and of course Vulkan.
- Public interface in C, in same convention as Vulkan API. Implementation in C++.
- Interface documented using Doxygen-style comments.
- Platform-independent, but developed and tested on Windows using Visual Studio.
- Error handling implemented by returning `VkResult` error codes - same way as in Vulkan.
- **[PyVMA](https://github.com/realitix/pyvma)** - Python wrapper for this library. Author: Jean-S<>bastien B. (@realitix). License: Apache 2.0.
- **[vulkan-malloc](https://github.com/dylanede/vulkan-malloc)** - Vulkan memory allocation library for Rust. Based on version 1 of this library. Author: Dylan Ede (@dylanede). License: MIT / Apache 2.0.
