Add options for up to 32x supersampling

[72374]

This is mostly useful for reducing flickering caused by aliasing, when playing games at the original resolution ("1x 224p"); but also for screenshots and videos¹ at higher resolutions.

20x is the highest amount of supersampling with which my "Core i7-12700K"-CPU² can still process F-Zero with a stable framerate of 60 fps in both bsnes-hd and RetroArch³ (performance in RetroArch was lower; up to 23x supersampling worked well in bsnes-hd). With 32x supersampling, the game slowed down to ~35fps.

I chose to add options in steps of 2 (12 to 20) or 4 (24 to 32); because each additional supersampling-multiplier has a smaller effect, and it does keep it easy to change between supersampling-options with hotkeys.

Image-comparison (F-Zero)

10x:

16x:

20x:

32x:

4096x:

Footnotes

1. Practically doable, even if the game is not playable at normal speed then, by using RetroArch to record a replay, and then increasing the supersampling- and resolution-settings for recording a video of the replay with the video-recording-feature, as the playback-speed of the resulting video does apparently match the expected framerate for the videogame-system. ↩

2. With energy-mode set to "Performance". ↩

3. If Gamemode is deactivated in the latency-settings of RetroArch, so that the efficiency-cores of the CPU are also used. ↩

[DerKoun]

Good idea, especially the larger steps for larger values. I'll add it to the next feature release. (No ETA, but I'm working on things)