I'm always playing with the settings on the video plugin, trying to get Paper Mario both looking better and doing so at high resolution.
Right now I'm hovering between 1024x768 and 1280x960 with 6xBRZ texture enhancement. On a 1080p display, that's filling a good bit of the screen. The itty bitty textures can only take so much, but BRZ is a great algorithm. GLideN64 has options for additional smoothing/sharpening filtering (probably just stock bilinear,) but the sharpening is horrendous and the smoothing causes weird little artifacts with this texture enhancement. It works better with HQ4x and 2x, which look great at ~1.5x res. It's also a little finnicky about the video resolution. HQ4x and family will scale at any weird resolution and it will blur, but it'll be organic. The distortion from resolution mismatch at these odd points of alignment with BRZ upscaling multipliers is worse, but it's overall crisper and cleaner when matched. Paper Mario actually runs at the n64's max res, which is 640x480. So for any of them to work without crunching too much, close to double res is needed. This ends up being okay, because BRZ happens to look better the more you crank the multiplier and resolution. HQ4/2x are better for lower resolutions. I let the base render resolution scale to the higher video res, too. You can go as far as 16x manually, but matching resolution with 4x MSAA is generally enough and Paper Mario can begin to develop lag/slowdown if you push the rendering too much... and it'll be right in those exact timing moments that it will consistently have that microchop. Even though things aren't 3D, the internal resolution for the geometry vectors still matters. In Paper Mario, everything generally looks flat, like sprites, but it's all regular 3D. It's just a mix of 2D and 3D meshes mapped to textures that are designed to look like paper sprites and scattered across a 3D space. If you let it draw the meshes at 480 while running at much above that resolution, the edges really smudge out. The game also does have some effects that are based on vector geometry, which will get abundantly clearer at high resolutions if the base resolution is higher too.
I'm getting to one of my favorite chapters. The spooky-ghosty stuff is always my favorite aesthetic.
Obviously a fair bit of distortion with this scaling algorithm if you view these full size. I think it looks surprisingly good, compared to the puddle it would be with bare upascaling. 480p is a preeeettttty tiny starting point, even at my ppi. What I really wish for is additional processing I've seen with other emulators. I think it might've been ZSNES that had a "TV mode" which gave the completely sharp, unfiltered, scaled pixel edges a very distinctly CRT-esque horizontal smudge and added faint, smooth scanlines. I need something like that on top of this. I think you can hook ReShade into this, too. I might be able to make it happen that way. I'd love to just run this into a real color CRT, though.
I made it to the mansion where Bow is.