Archive | novembre 2016

Small gamedev companies lacks interest in Vulkan

Last month I got interviews for a 3d dev position in a couple of companies near Paris. I mentioned in my resume that I already wrote DX12 and Vulkan code and as expected at some point the interviewers asked me my opinion on DX12 and if I got some performance improvements by using the API. I admitted that my experience is biased since RPCS3 initial GL implementation was not optimal so the performance figure I got were not representative of what can be achieved with DX12.

What surprised me is that my interviewers didn’t show lots of interest in Vulkan. Gamedev studio in Paris can be considered as middle sized ones, between 20 and 70 full time dev who works on several (often niche) titles at the same times for bigger editor. Although they are big enough to maintain their own 3d engine they can’t invest as much money as the big name in the industry. Hence technical choices are often dictated by time and budget constraints.

The first company I was interviewed by (which ships games on PC, PS4 and X1) explained that adding a new rendering backend is costly and that they won’t support Vulkan except if it was the API of the at that time unnamed Nintendo new console (it turns out it’s not the case, the Nintendo Switch is using a custom API, VNM. As far as I know Nintendo always used custom gfx API). With around 1% of market share Linux wasn’t considered as a viable target; neither was Android despite being the first or second most used platform. I suspect the poor state of 3d graphic in the Android ecosystem is to blame here and the web is plenty of horror
story when it comes to OpenGL ES programming. I think that a lot of the enthousiasm surrounding Vulkan comes from the promises of more reliable drivers on Android thanks to the thinner layer of abstraction and the externalization of debug checks. SoC vendors also seems more inclined to improve the situation with Samsung heavily promoting Vulkan support though footage of early demo of Unreal Engine 4 and their partnership with editors to bring Vulkan version of NFS No Limits and Vain Glory on Google Play.

The second company’s engine already has an OpenGL codepath enabling Mac support. While OpenGL and Vulkan are very different in design but they at least share the same shader language (GLSL) which ease any potential porting work (which is still a big task, Vulkan’s being a very verbose API). However, Vulkan was never talked about during the interview; the interviewers were rather interested about what DX12 could bring. The catch is that there’s probably as much work to port a DX11 engine to DX12 as to port it to Vulkan, both Vulkan and DX12 relying on the same gpu abstraction; and while DX12 has a one year head start in term of tool and driver support it’s hindered by the OS support. Although Windows 10 has already gained around 25% of OS market share 60% of the market is still running Windows 7 or 8.x and there isn’t free upgrade offer anymore which makes the adoption rate slower.

On the other hand in both interviews it was clear that support for a low overhead API wasn’t a very high priority. Their engine has made the switch on DX11 very recently to reach parity with PS4 and Xbox One and the dev doesn’t want to reenter a new development cycle right now. At least for Windows; the only way to use Compute Shader, the most popular feature of DX11 hardware gen, on OSX is through Metal API. OpenGL on OSX is supported up to version 4.1 since 2012 and there is no sign that it will change soon. Increasing Metal popularity among will reinforce iOS lead in the smartphone gaming market meaning Apple has no incentive to support the low level API used of their main competitor.