Vjylku

An important step towards 3D gaming was the ability to scale sprites or tiles by nonintegral factors. Examples of the former from the eighties were the arcade games Pole Position, Outrun, Space Harrier and Afterburner; a subsequent example of the latter was the SNES Mode 7, used in many games for that machine.

Accustomed to modern hardware, one tends to expect antialiasing; that is, for each screen pixel, the system locates the corresponding data pixel, and if the answer lands between two data pixels, instead of just picking one or the other, it calculates a weighted average of the two.

But https://arstechnica.com/gaming/2011/08/accuracy-takes-power-one-mans-3ghz-quest-to-build-a-perfect-snes-emulator/ says

I don't deny the advantages of treating classic games as something that can be improved upon: N64 emulators employ stunning high-resolution texture packs and 1080p upscaling, while SNES emulators often provide 2x anti-aliasing for Mode7 graphics and cubic-spline interpolation for audio samples. Such emulated games look and sound better. While there is nothing wrong with this, it is contrary to the goal of writing a hardware-accurate emulator.

This suggests the SNES did not actually have antialiasing.

According to https://en.wikipedia.org/wiki/List_of_Sega_arcade_system_boards

The Sega Model 2 is an arcade system board released by Sega in 1993. Like the Model 1, it was developed in cooperation with Martin Marietta, and is a further advancement of the earlier Model 1 system. The most noticeable improvement was texture mapping, which enabled polygons to be painted with bitmap images, as opposed to the limited monotone flat shading that Model 1 supported. The Model 2 also introduced the use of texture filtering and texture anti-aliasing.

This suggests Sega arcade machines likewise did not have antialiasing before 1993. A surprising conclusion from today's perspective, but then, the transistors required for the extra calculations might've been a significant cost in those days, and arcade games were fast-moving and CRT TV displays were somewhat blurry anyway. And certainly it would not have been affordable in software on eighties-vintage CPUs.

Are the above inferences correct? Did antialiasing hardware only start being available in arcade and home games machines in the early to mid nineties?

There's something of a conflation here of antialiasing and filtering, I think. Antialiasing is literally preventing things from adopting aliases — e.g. if a diagonal line looks like a staircase rather than a diagonal line, it has adopted an alias. So you can imagine the same thing happening to textures as they rotate or take awkward angles. But it's always about accurately portraying the information you have.

Conversely, bilinear filtering is just a different way of guessing at what is between the information you have. It's about generating extra information — specifically positing that there's a linear gradient between every source pixel and the next, rather than a hard edge.

That being said: no, the SNES does neither. It's a simple nearest-neighbour colour grab only. Ditto for the scaling systems that precede it — including the Lynx in the home (and anywhere else you want to take it; I suggest the battery shop) and arcade machines like Sega's.

This is true up to the Saturn and Playstation. The Nintendo 64 has bilinear filtering, and everything after that unambiguously has both*.

So I believe the sources are correct.

*) you can technically fake antialiasing on anything with subpixel precision and alpha transparency by drawing multiple passes with slightly adjusted coordinates. So an N64 could do that, it'd just be expensive.