There will soon be a 'quasi-VI filter' mode built into Parallel N64's Vulkan renderer. What this is, is effectively a cut above what the RDP's regular VI filter would be able to do.
In essence, we apply NNEDI 3x together with 2-pass anti-aliasing. The results are impressive, and it really helps smooth out both 2D and 3D visuals. We feel confident that when this is released, users will no longer feel that they are being shortchanged graphically when compared to say a HLE OpenGL-based renderer.
Included is a screenshot gallery -
We are going to provide several quality modes for this quasi-VI filter - so that it can scale from say GTX 1050/1060 all the way to 1080/Ti. The very high and ultra quality modes will probably consist of NNEDI 3x at 4x FBO scale + 4-pass anti-aliasing.
There will also be the ability to turn dithering on/off. At the higher-quality VI filter modes, by turning this off you can significantly improve image quality.
Also, we are working on the PPSSPP core and Supermodel core!