@vaihei Ok, well I have such a project. The problem is it's VERY long term and quite complicated. I'm trying to do procedural planets up to a procedural galaxy. This will be for an eventual space empire sort of game. You can look at my blog for videos. It's now been ported to DirectX12 (From DirectX11), and I have incorporated Dear IMGUI as a temporary GUI. It also has basic terrain collision so the stand in ball now collides with and slides over the terrain.
There is still a LOT to be done on it: Animation, better rendering, more physics, loading of external assets etc. This is not an open-source project since it will be the core of my game, and it would be like giving away most of my work to other similar projects. However, I'm open to collaboration with the right person or people.
The engine itself is double precision CPU side to support large planets, and uses the moving terrain around the camera trick to support good precision GPU side. Most things are built with smooth voxels, something like marching cubes but with prisms. I will also support sharp corners for buildings later, but for now it's just straight marching cubes, but with LOD. I am mainly concentrating on the geometry right now, so if someone wants to take up the rendering side that would be cool. But there are many other areas that can be worked on. You would need to learn HLSL (which is very easy) for the rendering but everything else is in C++. This is NOT like a standard engine as it will generate most things internally. It also generates and refines at run time using fractal functions. I'm working on procedural trees right now.
You should probably be sort of a self-starter to get involved. If you are unsure you want to get into it, it's better to look for something that suits you better. Also, I barely use the standard library and I have my own heaps which have built in containers. On the upside there is no time pressure. I would require an NDA because I have been working on the code for quite a while, I have a lot of time invested, and I don't want to risk being ripped off. But should this make money at some point, those involved will take a share. We will work that out if you are interested. Also, everything is kind of experimental, so the code is messy in places since it's been worked over so many times. This isn't an ECS game engine. It's specifically designed for the need of my particular game.
If it all comes together the eventual game should be pretty cool but that's a ways off. If I haven't scared you off ? let me know. Finally I'm in Russia, just in case that's an issue, but I'm actually American.