Vulkan is a graphics and compute application programming interface or API from the Khronos Groups that was intended as a successor to the OpenGL graphics API. It was first released to the public in February 2016 and has undergone numerous iterations to introduce new features and capabilities. This API competes against OpenGL and other alternatives like the Direct3D of the Microsoft DirectX API suite and the Metal graphics API from Apple. Nevertheless, because it is positioned as an improvement to the older OpenGL and is marketed to be platform-independent, it intends to become the better API for graphics programming. This article lists and discusses the advantages and disadvantages of Vulkan graphics API.
Pros of Vulkan: Advantages and Notable Features
OpenGL became one of the more popular graphics APIs following its first introduction in June 1992. It continues to do so because of its cross-platform support. But it has limitations. Vulkan intends to address the shortcomings of OpenGL while also banking on the same cross-platform appeal. The following are its specific advantages and notable features:
1. Low-Level and Low-Overhead API
One of the main advantages of Vulkan, especially when compared to OpenGL, is that it is a low-level and low-overhead graphics API. It is similar to Direct3D and Metal in this regard. OpenGL has some low-level and high-level aspects. Vulkan enables graphics programmers or software developers to have more or fine-grained control over the processors and have more flexibility when it comes to implementing custom graphics rendering techniques and features. It also enables the development of programs or apps with minimal resource usage.
2. Unified API for Desktop and Mobile
This graphics API provides a single API for both desktop devices or personal computers and mobile devices. Take note that OpenGL has two separate graphics APIs for these two platforms. The standard OpenGL is for desktops while the OpenGL for Embedded Systems or OpenGL ES is designed for mobile platforms like smartphones, tablet computers, and handheld gaming consoles. The advantage of having a unified API for both platforms centers on reducing the time and costs it takes for developers to create programs or applications.
3. Available on Multiple Platforms
Another advantage of Vulkan is that it is a cross-platform graphics API. It is available on multiple operating systems. These include Windows, Linux, Android, BSD Unix, Haiku, and QNX. It is also supported on the system software of the Nintendo Switch and Nintendo Switch Lite. Vulkan also runs on Raspberry Pi and the Fuchsia and Stadia operating systems. It is also compatible with Apple platforms like macOS, iOS and iPadOS, and tvOS using the free MoltenVK software library that wraps over the proprietary Metal graphics API standard of Apple.
4. Both a Graphics and a Compute API
It is also both a graphics and compute API. This means that it provides a unified approach to handling both graphics rendering and general-purpose computation. It uses unified shaders that can be tailored for specific tasks. It is also designed for multi-core and multi-threaded CPU architecture. Take note that DirectX 11 and OpenGL 4 do not scale well on multi-core processors. It also reduces the load on the CPU through batch processing and other low-level optimizations and frees up processor resources for other computation tasks.
Cons of Vulkan: Disadvantages and Key Limitations
Vulkan is still considered new compared to both OpenGL and Direct3D. It has feature and performance advantages over its predecessor and has a cross-platform advantage over the alternatives from Microsoft and Apple. However, despite its promises, it still fails to become a dominant graphics API. Below are its disadvantages and limitations:
1. Learning Curve and Complexity
The fact that this is a low-level graphics API means that it is harder to implement than high-level alternatives. It requires a deeper understanding of graphics programming and graphics hardware. Developers are responsible for managing detailed system resources to ensure that the graphics pipeline runs efficiently. The increased control over the hardware also makes the entire development environment prone to errors. Furthermore, due to this complexity, another disadvantage of Vulkan is that it increases overall development time and costs.
2. Compatibility and Porting Issue
Vulkan is not directly compatible with other graphics APIs. The workaround is to use porting layers. The Vulkan Portability Initiative was organized to address platform fragmentation. Remember that it can work with Metal via the MoltenVK layer. It can also work with OpenGL and DirectX 9-11 via Ashes, and with DirectX 12 via Microsoft Dozen. The problem with using these porting layers is that it increases development complexity and can introduce performance overhead that negates the performance benefits and potentials of Vulkan.
3. Concerns Over Hardware Support
The initial specification for this graphics API stated that it could be implemented on hardware that supports at least OpenGL 4 and OpenGL ES 3.1. However, because it requires new graphics drivers, this claim is not always true, and existing hardware that supports compatible versions of OpenGL will have drivers for Vulkan available. Nvidia also noted that OpenGL remains a great option for a lot of applications or use cases because using it comes with a significantly lower development burden while providing great overall performance.
4. Not a Universal API for All Use Cases
It is also worth mentioning that Vulkan is not the best fit for all use cases. OpenGL remains suitable for individuals who want to venture into graphics programming for the first time because it provides foundational concepts that can be applied to other graphics APIs. The complexity of a low-level API also outweighs the potential performance gains. DirectX and its Direct3D graphics API are more suitable for Windows-specific and Xbox-specific platforms. The steeper hardware requirements also mean that it is not suitable for some older hardware.
Takeaways: Advantages and Disadvantages of Vulkan
Vulkan has been positioned as a next-generation cross-platform 3D graphics API. This is its main advantage over platform-dependent graphics APIs and older cross-platform graphics APIs. However, because it is still new and that adoption is still not as fast and extensive, it still has not dethroned OpenGL in terms of a more universal application and graphics APIs like Direct3D and Metal in terms of hardware optimization. Nevertheless, in the following years, as it becomes more popular across the community of software developers and hardware manufacturers, it is possible that it can emerge as a dominant graphics API because of its platform dependence and the availability of porting layers that address compatibility and fragmentation issues.
