Some weird things in PCem...

[DSN]

Hello all!

I found some weirdness in PCem (probably bugs).

(1) The Machine window shows any program that use 640x480x4 mode running in 320x480, like X-COM Apocalypse's DOS installer:

320X480.png (77.03 KiB) Viewed 9655 times

This happens in most of the graphics cards I used previously, including S3Virge/DX, Stealth 3D 2000 and all the Cirrus Logic cards (and even in plain VGA). Happens also in Windows (and games), 640x480x8/16 appears as 320x480x8/15, 320x200x8 appears as 160x200x8, 800x600x16 appears as 400x600x15.

(2) I found stuttering CD audio in some DOS games (like Earthworm Jim 1/2, Destruction Derby, Ignition and others) even with 100% (full) emulation speed. I not sure if this is because of the CDROM speed (my emulated PC is set to 6x speed, happens in 4x too).

(3) In both Win95 and 98, when the desktop is set to 24bit color, purple and/or green glitches/corruptions appear on the screen (in my case, closing Display Properties after setting desktop to true color, reopening it and going to the Effects tab I can see purple and green corrupted desktop icons, as shown below). Happens in both Stealth 3D 2000 and VirgeDX. I noticed that this do not occur in v14 and older versions.

glitch.png (138.97 KiB) Viewed 9655 times

If anyone knows that this is bugs, please let me know.

[omarsis81]

(3) In both Win95 and 98, when the desktop is set to 24bit color, purple and/or green glitches/corruptions appear on the screen (in my case, closing Display Properties after setting desktop to true color, reopening it and going to the Effects tab I can see purple and green corrupted desktop icons, as shown below). Happens in both Stealth 3D 2000 and VirgeDX. I noticed that this do not occur in v14 and older versions.

What driver version are you using?

[DSN]

The one that comes with Win98SE. Also occurs with driver dated 8-21-1997 in both Win95/98.

[CryptidWorks]

The one that comes with Win98SE. Also occurs with driver dated 8-21-1997 in both Win95/98.

What 2D Graphics Card?

I'm using an S3 Virge with the default Win98 Drivers and noticing no issues

[DSN]

The Stealth 3D 2000. I am using the default Win98 drivers also.

[DSN]

What PCem version you are using? I'm using v15, while I wait for next version.

[DSN]

PCem is very slow with PMMX233 on my Core 2 duo P7550 and I'm actually using Win98 for testing, not for playing.

[CryptidWorks]

Version 15, and I explained to you in the other thread:

That ancient CPU is way below the pay grade to emulate anything but the slower chips PCEM offers. A Pentium 233 on that thing is asking way to much of both PCEM and your hardware.

[DSN]

Yes, I know. I'm using only for testing and not for general use. Perhaps the Matrox Mystique won't contain any display bugs, like the Stealth 3D 2000, S3 Virge DX and S3 Trio64 have.

[DSN]

As I mentioned earlier, the CD music in Earthworm Jim 2 is stuttering even with 4x CDROM speed I tested on my DOS system, 2x speed will probably have stuttering music also, I will test later. Anyway I don't know if this occurs because of the CDROM speed, probably a bug in PCem.
I would like to know if anyone has stuttering music, like me, just a curious question.

[CryptidWorks]

As I mentioned earlier, the CD music in Earthworm Jim 2 is stuttering even with 4x CDROM speed I tested on my DOS system, 2x speed will probably have stuttering music also, I will test later. Anyway I don't know if this occurs because of the CDROM speed, probably a bug in PCem.
I would like to know if anyone has stuttering music, like me, just a curious question.

Is the emulation at full-speed? The emulation dropping speed will cause sound stuttering.

[DSN]

Yes, is at 100% speed when playing most DOS games, but in DOS text mode is 95-96%.

[CryptidWorks]

Yes, is at 100% speed when playing most DOS games, but in DOS text mode is 95-96%.

I know I've had speech glitches with some isolated games in isolated instances with a PCI-128 but not music glitching

[DSN]

And one more thing: you noticed the resolution in the Machine window? Is showing the original resolution or the same I explained earlier?

[CryptidWorks]

And one more thing: you noticed the resolution in the Machine window? Is showing the original resolution or the same I explained earlier?

I'm not dead sure because I don't know if I have any games installed that use 640x480x4bit ATM. I do know the reslution reads correctly as 1024x768 at the desktop and the launcher that comes with Clue Finders 6th Grade reads as 800x600 (but the game itself reverts to 320x240) so it's not stuck.