Is there an industry advantage to divesting from OpenGL and splitting into a device specific APIs with hugely overlapping features, yet I’m sure, an impedance mismatch? Since most devs are targeting Unity or some other batteries included game engine, does it just not matter anymore?

It never mattered outside FOSS circles, in the 8 and 16 bit days every platform was a special snowflake, so the industry grew porting contractors, platform specialized studios and middleware.

If you dive into something like Ogre3D, you will see that actual 3D rendering API is a tiny slice of the whole cake, let alone in something like Unreal.

The total impedance matches of all device specific platforms you might target is often less than the impedance mismatch of just OpenGL vs. the real world.

No game developer is using raw Vulkan, Metal or DX12. these APIs aren't the same level of abstraction as OpenGL...

Vulkan is AMD's Mantle open-sourced, it's far too low level for devs to waste time with, it's a target for game engines and renderers.

I think both your sentences are incorrect.

Tons of AAA game developers make their own engine and therefore work directly with the APIs while making an abstraction layer for their higher level game developers.

Vulkan is also not just Mantle open sourced. It’s a significant deviation from the original Mantle API. Mantle was a starting point but what emerged as Vulkan was quite different.

Not just AAA. It's certainly a minority, but custom engines aren't that uncommon even among indies. The last game I finished was Return to Monkey Island released two weeks ago, built on a custom engine with custom Vulkan and DirectX 12 renderers (and I guess the macOS version probably uses Metal).

I’m curious why they went full-on Vulkan/DX12 instead of just DX11. It’s an adventure 2D game, the performance requirements aren’t that high, and DX11 still has the most stable and performant drivers out of all the APIs.

Possibly their next game is less refined so they learned the dev stack on something that was less up for debate. Now the know the dev stack to focus on content.

> Tons of AAA game developers make their own engine

Recently a bunch switched to Unreal. Are there THAT many that still maintain their own? Seems like it's just big studios and less than a dozen. Even a massive company like Square Enix is now using Unreal for many projects.

Almost all Sony first party studios use custom engines, even when they support PC. Most Nintendo first party games are custom engines. The majority of Microsoft first party games are custom engines.

Ubisoft use custom engines, EA use custom engines.

Call of Duty is a custom engine (derived from idTech)

If you go to the GDC YouTube channel ( https://youtube.com/c/Gdconf ) you can see the range of game specific things that these studios are working on that using an off the shelf engine is limiting

I also recommend looking at the presentations on http://advances.realtimerendering.com/

Ubisoft have about 5 engines themselves. When Microsoft acquires Acti-Blizz, they'll have close to a dozen engines under their umbrella as is, I think.

UE being picked up by a AAA studio is news, because gamers associate UE with extreme fidelity graphics. A studio using a proprietary engine is boring because it won't matter one bit for 99% of people, and is modus operandi, basically.

Edit: remembered SteamDB has a rough breakdown based on manual rules, so a lot of engines aren't picked up, but it's still interesting - https://steamdb.info/tech/

Proprietary engines tend to be more common on consoles I think - Steam has a lower barrier to entry overall, so it doesn't filter out the smaller projects as much (which are more likely to use an off-the-shelf engine).