[modeless]

I agree that Vulkan isn't necessary, but neither is OpenGL, or a GPU at all. A software rasterizer would be the way to go. Even a mobile CPU should be able to rasterize 2048 polygons per frame at 256x192 using fixed point math. That's almost Quake 1 levels of graphics, and Quake 1 was software rendered in 1996 on 75 Mhz Pentium 1s.

Edit: Reading other articles on the site, it seems like they started with a software renderer. I wonder why they decided to try OpenGL?

[Karuma]

People like to increase the internal resolution to render at 4K or more, which I believe is much faster when using hardware to do it.

[modeless]

Wow, yeah, that would be a reason to use hardware. Here's what that looks like: https://youtu.be/tvGVqGQIDGA

Kind of an interesting aesthetic. It looks less terrible than I expected. I think it would be interesting to apply some of the recent machine learning based upsampling techniques on DS games too.

[pcwalton]

4K at 60 FPS is basically impossible on CPU.

[dleslie]

People like to add shaders to their emulation these days; crt filters, colour adjustment, samplers, etc.

[Jasper_]

It should be easy enough to upload the final rasterized texture to the GPU and apply filters there.

[dleslie]

That doesn't help when geometry is a target for shading.