@all, regarding the 'black border issue'
As mentionend above (and much earlier in this thread), there are games with proper built-in 480p mode but when enforcing 480p with GSM instead they suffer from the black borders to the left and the right. If we'd know their approach to achieve a proper full screen GSM could try to mimic it to get rid of the black border issue.
Unfortunately it seems that this won't be possible. Here is my theory:
- The games suffering from the 'black border issue' are the ones that use a smaller frame buffer, typically 512x448 or 512x512 (I think there is no discussion on that). The developers simply made a trade-off between image quality and performance.
- Some of these games still offer a proper fullscreen, built-in 480p mode. These games not only switch the vmode when activating the built-in 480p mode, but also switch to a full size frame buffer, typically switching from 512x448 to 640x448.
I really don't understand why they didn't simply use the 640x448 frame buffer for the interlaced mode in the first place, but that's how it is (according to GSDX, graphics plugin for PCSX2).
So if GSDX isn't lying, we can't learn anything from these games. Instead, it seems like it simply isn't possible to get fullscreen 480p on games with smaller frame buffers. I mean, if there was another, easier way to achieve a full screen image by using some GS function, why did the bother with such workarounds?
Some games that seem to switch to full size frame buffer when enabling the 480p mode:
God of War: 512x448 -> 639x448
God of War 2: 512x448 -> 639x448
Resident Evil 4: 512x448 -> 640x448
Shadow of the Colossus: 512x448 -> 640x448
SSX3: 512x448 -> 640x448
Similar, but using not quite full size frame buffers:
Tomb Raider Legend: 512x448 -> 576x416
Tomb Raider Anniversary: 512x448 -> 576x416
(Notice how they decreased the height of the frame buffer while increasing the width. I guess they didn't increase the frame buffer to real full size for performance reasons and then had to decrease the height to maintain the correct aspect ratio (?).)
One game, where the official built-in 480p mode suffers from 'black border issue' :
Hitman Blood Money: 512x448 -> 512x448
(It's if the deveopers thought 'Just choose the setting 'wide' on your HDTV, then the aspect ratio is approx. 4:3 ...' )
Now for the analog scaling of the screen size. Some games allow you to seemless increase/decrease the screen size. Maybe they achieve that by using an unkown GS function, then we really should know how exactly this is done. Or it's done by software (is this possible without a big performance/image quality drop?).
The only games I found offering that feature are retro compilations (seems like a bad sign to me):
Capcom Classics Collection
Capcom Classics Collection 2
Midway Arcade Treasures 3
Sega Genesis Collection