[General Topics] Menneisyys:
1.4.1.1 Downscaling

If you squeeze a 320*2x0 (where x is either 0 or 4) image into Portrait orientation, you practically throw away every fourth column (and, if you keep the aspect ratio – which is NOT necessary and can be configured in ScummVM -, also rows). That’s not much of a loss and text, generally, remains pretty well readable. (This also applies to square-screen, 240*240 devices). An example of this downscaling can be seen in HERE.

Incidentally, the same happens when running 320*2x0 games on the 240-pixel-wide screen of current square-screen models. The square-screen converter (the one that renders 320*2x0 games on these models) works exactly the same way as the Portrait converter.

The situation is worse with traditional, low-resolution 176*220 Smartphones. First, they’re only used in Landscape mode but, even then, the text readability becomes definitely worse than with QVGA screens in Portrait mode because of the width of 220 pixels (which is 20 pixels less than the width of the QVGA screen in Portrait mode). Most games are on the verge of playability on these Smartphones.

Example screenshots of a 176*220 Smartphones running 320*200 games are HERE (GUI menu), HERE and HERE.

The worst happens when you try to downscale VGA to QVGA (because you play a VGA game on a QVGA handheld), you practically throw away every other row and (!) column. This may result in major quality degradation, particularly text readability-wise. Needless to say, you can’t downscale VGA to 240*240 square-screen devices, let alone 176*220 Smartphones – then, about two of every three pixel rows / columns should be thrown away. This also means you can’t play VGA games on a QVGA device otherwise allowing Portrait play (for example, the HP iPAQ 2210) in Portrait mode either, unlike with traditional 320*200 games.

An example of the results of VGA -> QVGA downscaling can be seen HERE and HERE; the latter using zooming. These are Touche screenshots; I’ve provided some VGA vs. downscaled QVGA screenshots with Broken Sword.

Note that zooming only works with vertical zooming (zooming into either the upper or the lower half of the screen): other people have also recommended using four quarters to make it possible to use a 1:1 rendering mode, as is the case with, say, PocketDOS.

1.4.1.2 Upscaling on VGA devices

Note: this section ONLY applies to VGA device users. Just skip it if you “only” have a handheld with a QVGA (or even worse) screen.

If you run ScummVM on a VGA device, you’ll quickly find it uses only the quarter of the available screen estate (as can be seen in HERE) in both games and when using the ScummVM GUI. To quickly fix this, click Options in the game launcher screen and select for example 2xSAI in the “Graphics mode” list as can be seen in HERE. Click OK. After a restart, both the GUI and non-VGA games will use the full screen estate – but in Landscape only. (This means if you are sensible to the Landscape polarization problems of your VGA Dell Axim x50v/x51v, you will NOT want to use pixel doubling, but stay with the original mode because it offers Portrait, no matter how tiny the actual game screen will be.)

Note that there are several options in this drop-down list. The original documentation of ScummVM (see section 5.3 Graphics filters) emphasizes there are major speed / CPU usage differences between the different video modes. Using Windows Mobile, I haven’t encountered ANY difference (including CPU usage and animation speed), except for the simple pixel doubler 2x. That is, you can safely use any of these options (except for the blocky 2x) – for example, 2xSAI. You won’t want to test the other modes.

1.4.1.2.1 Pixel doubling (2x mode) vs aliasing filters

As has already been pointed out, the standard, non-enhanced 2x mode results in blocky, badly pixelizated results. ALL the other options result in a FAR better visual experience as can be seen in for example HERE. I REALLY recommend comparing the “blockiness” of both the icons, the text and the background images. Only the blind don’t see the difference.

All in all, NEVER use the 2x mode. The other modes deliver MUCh prettier modes – as if the original game were native VGA, and not just a low-res QVGA one.

1.5 Recommended links

My other articles on emulators and game interpreters – they are a MUST.

Adventure Gaming on the Go by David Dolan (pretty old and outdated, but still a good read)

See the following links for more info on (some) of these games:

Cinematique evo1 engine (Note that Cruise for a Corpse (which is no longer based on the evo1 engine) is NOT supported as yet. See THIS for more info.)

Future Wars (asks for code; there is no code accessible anywhere)

Operation Stealth

GOB engine: Bargon Attack, Gobliiins, Gobliins 2, Goblins 3, Ween: The Prophecy

Adventure Soft’s Simon the Sorcerer series

LucasArts' games:

Maniac Mansion

Zak McKracken and the Alien Mindbenders. Note that the vastly enhanced FM Towns version wasn’t converted back to the IBM PC as can also be read in HERE

Indiana Jones and the Last Crusade: The Graphic Adventure

Loom

Day of the Tentacle

The Dig

Full Throttle

The Curse of Monkey Island.