GPU support on Raspi 4

[pigkachu]

We are developing our own OS on Raspi, and we want to use GPU of Raspi4, even Raspi5. I wonder if there is a GPU support from circle, which can be migrated to our OS. However, I only find support for VC4, which is the GPU on Raspi3, instead of VC6 on Raspi4. I wonder when it could be supported in Circle. Or how to use VC6 GPU without Linux Kernel?

[rsta2]

It is unlikely, that Circle will support the VC6. This would be much effort and I don't even know, if the necessary information is available to the public. There are other tasks, which are more important at the moment (e.g. RPi 5 support). Unfortunately I cannot help you.

[makuto]

The only bare metal project with GPU support on Pi 4 I've found is this one. It looks like if you want GPU support, you'll need to read the Linux kernel driver and figure out how to port it to your bare metal system. See this issue.

[makuto]

I have been making good progress on this in my fork. See the header and the example. As you can see, the example has most of the code and is quite messy, but I plan on greatly bolstering it in the coming weeks. Don't expect any OpenGL/Vulkan style api or anything, and the shader compiler problem is still up in the air, but at least there's an exciting seed here. I was rendering 100k triangles at reasonable framerates today with the GPU!

I'm making it a single header so it should be very easy to bring to Circle proper once it's ready.

Another good news: the Raspberry Pi 5's VPU is looking to be very similar (the driver in Linux is very nearly the same), which means this work should benefit both 4 and 5.

[JoeStrout]

Hey @makuto, your project sounds great! The example link is giving me 404 though. I read through your header file but, though I have some experience with low-level 3D graphics, a working example or two of how to use it would be enormously helpful. Got any you can share?