Low screenmode problem in OS 3.9

Bamiga2002 · 01 August 2012, 10:01

I wanted to set 320x256 as resolution on my Workbench but instead a normal lowres screen it gave me a messed up screen. In Picasso96Mode/Screenmode-prefs test it displays normally. What's up?

thomas · 01 August 2012, 12:51

Seems like you gfx card driver does not allow bitmaps wider than the screen.

Workbench screen must be at least 640 pixels wide. If you choose a screen mode that is not that wide (like 320 x 256) it gives you an autoscroll screen with a 640x256 bitmap on a 320x256 screen (i.e. you can scroll left and right with the mouse).

In your case it seems that the gfx card does not cut the 320x256 section from the 640x256 bitmap correctly but instead makes some kind of interlace, i.e. every second row from the left side of the bitmap and every other row from the right side of the bitmap.

duga · 01 August 2012, 13:02

I guess OS 3.5/.9 were meant to use at least 640x480.

Bamiga2002 · 01 August 2012, 14:49

This problem is on a Voodoo3/Mediator screen. But using PAL/NTSC low resolution it displays just OK. Is there any workaround for this?

thomas · 01 August 2012, 15:11

Why do you want 320x256 on a gfx card? I agree that 1600x1200 might be too big for an Amiga, but what is wrong with 640x480 or 800x600?

Bamiga2002 · 01 August 2012, 23:15

I wanted to try window-mode for Exult (Ultima VII port) because fullscreen fucks up the colors totally. I think the fullscreen mode uses a PC-mode that won't display the right colors. But the screen is OK otherwise, no other distortion than the color palette. Exult has a window-mode option at 320x200 but trying to switch WB to that won't work at all. I remember the colors were right with BVision.

I guess I'm out of luck on this one...

Bamiga2002 · 02 August 2012, 09:50

If someone wants to have a go I just uploaded Ultima VII in EAB upload FTP (Bamiga2002). There are 2 packs: "Ultima VII" and "AMidi".

thomas · 02 August 2012, 15:09

Why don't you try windowed mode on your normal Workbench screen? You'll get a small window on a bit screen, but that does not matter only to check if the colors are right. And if the colors are wrong in windowed mode, too, all the effort to create a small gfx card screen mode is unnecessary.

thomas · 02 August 2012, 15:52

BTW, you could use ModePro to force Exult's screen into 32bit mode.

Bamiga2002 · 02 August 2012, 17:29

Now why didn't I think of that! I already have ModePro installed

. Thanks Thomas I'll try it out

I'll post result later...

EDIT: this could do the trick also: Lupe

Minuous · 03 August 2012, 03:02

Quote:

Originally Posted by duga

I guess OS 3.5/.9 were meant to use at least 640x480.

No, I have used lower-resolution screenmodes on OS3.9 without problems and such a restriction has never been mentioned in any of the documentation, so I suspect that isn't the problem.

Bamiga2002 · 03 August 2012, 13:27

Quote:

Originally Posted by Minuous

No, I have used lower-resolution screenmodes on OS3.9 without problems and such a restriction has never been mentioned in any of the documentation, so I suspect that isn't the problem.

Would you care to shed some advice how I could fix this? What settings to change etc. Have you used P96 or CGX low screenmodes succesfully on WB? Btw. when I launch etc WarpHexen there's no problem with the 320x200 display, only on WB...

Bamiga2002 · 06 August 2012, 21:23

Okay, ModePro is good but this time it didn't do the trick. Tried to promote Exult to all kinds of screenmodes (24, 32 bit) but the colors are wrong. In window they display fine. I don't know if it's a palette issue...

Minuous, could thou still pass a hand here if you have any ideas.

Minuous · 07 August 2012, 03:23

I've never had a real graphics card, so I probably am not the best person to ask. I've just run in AGA on a real Amiga and AGA/RTG on WinUAE.

matthey · 07 August 2012, 05:15

I have the same display problem here. It's probably a bug in the Elbox P96 driver or Workbench. There may not be a workaround to a bug. I do recall low res RTG working on Workbench with a gfx card at one time.

Bamiga2002 · 08 August 2012, 09:51

OK, so it's a driver limitation. I did some tests and it seems that when I tick "doublescan" in Picasso96Mode for a screenmode it displays Workbench wrong like in the pic in 1st post (note: games work OK in a screen). Seems so that 640x400 is the lowest screenmode that fills the entire display without distortion/scanlines. Maybe at Elbox they thought no-one would use WB with a lower screenmode setting.

Would be cool though to have that option still, just because you could. Meanwhile I switch to 640x400 Workbench and launch Exult in 400x280 window which seems to update fast enough...

Bamiga2002 · 21 August 2012, 00:02

640x480 seems to be the lowest screenmode which displays Exult fine with the right aspect ratio. The lowest I could get Workbench to display without gfx corruption was 640x200 which is quite useless since the aspect ratio goes bonkers. So I ended opening up a 640x480 WB display and play Ultima VII in a custom 424x265 res window.

A nice game really

01 August 2012, 10:01	#1
Bamiga2002 BlizzardPPC'less Join Date: May 2004 Location: Finland Age: 46 Posts: 3,210	Low screenmode problem in OS 3.9 I wanted to set 320x256 as resolution on my Workbench but instead a normal lowres screen it gave me a messed up screen. In Picasso96Mode/Screenmode-prefs test it displays normally. What's up? Attached Thumbnails

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Problem with changing Screenmode after LoadView/WaitTOF	StingRay	support.WinUAE	4	24 September 2012 09:07
FS-UAE 1.1.1 screenmode problem when P96 active	PHabermehl	support.FS-UAE	19	06 April 2012 14:53
Problem with very low Chipmem... (Startup-Sequence?!)	Ebster	support.Apps	15	25 February 2010 21:41
Chaos Engine AGA screenmode problem, can it be fixed?	TjLaZer	support.Games	0	05 September 2006 07:42
winuae screenmode and refreshrate problem	PseudoDOS	support.WinUAE	0	28 May 2003 21:04

01 August 2012, 12:51	#2
thomas Registered User Join Date: Jan 2002 Location: Germany Posts: 7,026	Seems like you gfx card driver does not allow bitmaps wider than the screen. Workbench screen must be at least 640 pixels wide. If you choose a screen mode that is not that wide (like 320 x 256) it gives you an autoscroll screen with a 640x256 bitmap on a 320x256 screen (i.e. you can scroll left and right with the mouse). In your case it seems that the gfx card does not cut the 320x256 section from the 640x256 bitmap correctly but instead makes some kind of interlace, i.e. every second row from the left side of the bitmap and every other row from the right side of the bitmap.

01 August 2012, 13:02	#3
duga Registered User Join Date: Nov 2010 Location: Sweden Posts: 528	I guess OS 3.5/.9 were meant to use at least 640x480.

01 August 2012, 14:49	#4
Bamiga2002 BlizzardPPC'less Join Date: May 2004 Location: Finland Age: 46 Posts: 3,210	This problem is on a Voodoo3/Mediator screen. But using PAL/NTSC low resolution it displays just OK. Is there any workaround for this?

01 August 2012, 15:11	#5
thomas Registered User Join Date: Jan 2002 Location: Germany Posts: 7,026	Why do you want 320x256 on a gfx card? I agree that 1600x1200 might be too big for an Amiga, but what is wrong with 640x480 or 800x600?

01 August 2012, 23:15	#6
Bamiga2002 BlizzardPPC'less Join Date: May 2004 Location: Finland Age: 46 Posts: 3,210	I wanted to try window-mode for Exult (Ultima VII port) because fullscreen fucks up the colors totally. I think the fullscreen mode uses a PC-mode that won't display the right colors. But the screen is OK otherwise, no other distortion than the color palette. Exult has a window-mode option at 320x200 but trying to switch WB to that won't work at all. I remember the colors were right with BVision. I guess I'm out of luck on this one...

02 August 2012, 09:50	#7
Bamiga2002 BlizzardPPC'less Join Date: May 2004 Location: Finland Age: 46 Posts: 3,210	If someone wants to have a go I just uploaded Ultima VII in EAB upload FTP (Bamiga2002). There are 2 packs: "Ultima VII" and "AMidi".

02 August 2012, 15:09	#8
thomas Registered User Join Date: Jan 2002 Location: Germany Posts: 7,026	Why don't you try windowed mode on your normal Workbench screen? You'll get a small window on a bit screen, but that does not matter only to check if the colors are right. And if the colors are wrong in windowed mode, too, all the effort to create a small gfx card screen mode is unnecessary.

02 August 2012, 15:52	#9
thomas Registered User Join Date: Jan 2002 Location: Germany Posts: 7,026	BTW, you could use ModePro to force Exult's screen into 32bit mode.

02 August 2012, 17:29	#10
Bamiga2002 BlizzardPPC'less Join Date: May 2004 Location: Finland Age: 46 Posts: 3,210	Now why didn't I think of that! I already have ModePro installed . Thanks Thomas I'll try it out I'll post result later... EDIT: this could do the trick also: Lupe

06 August 2012, 21:23	#13
Bamiga2002 BlizzardPPC'less Join Date: May 2004 Location: Finland Age: 46 Posts: 3,210	Okay, ModePro is good but this time it didn't do the trick. Tried to promote Exult to all kinds of screenmodes (24, 32 bit) but the colors are wrong. In window they display fine. I don't know if it's a palette issue... Minuous, could thou still pass a hand here if you have any ideas.

07 August 2012, 03:23	#14
Minuous Coder/webmaster/gamer Join Date: Oct 2001 Location: Canberra/Australia Posts: 2,673	I've never had a real graphics card, so I probably am not the best person to ask. I've just run in AGA on a real Amiga and AGA/RTG on WinUAE.

07 August 2012, 05:15	#15
matthey Banned Join Date: Jan 2010 Location: Kansas Posts: 1,284	I have the same display problem here. It's probably a bug in the Elbox P96 driver or Workbench. There may not be a workaround to a bug. I do recall low res RTG working on Workbench with a gfx card at one time.

08 August 2012, 09:51	#16
Bamiga2002 BlizzardPPC'less Join Date: May 2004 Location: Finland Age: 46 Posts: 3,210	OK, so it's a driver limitation. I did some tests and it seems that when I tick "doublescan" in Picasso96Mode for a screenmode it displays Workbench wrong like in the pic in 1st post (note: games work OK in a screen). Seems so that 640x400 is the lowest screenmode that fills the entire display without distortion/scanlines. Maybe at Elbox they thought no-one would use WB with a lower screenmode setting. Would be cool though to have that option still, just because you could. Meanwhile I switch to 640x400 Workbench and launch Exult in 400x280 window which seems to update fast enough...

21 August 2012, 00:02	#17
Bamiga2002 BlizzardPPC'less Join Date: May 2004 Location: Finland Age: 46 Posts: 3,210	640x480 seems to be the lowest screenmode which displays Exult fine with the right aspect ratio. The lowest I could get Workbench to display without gfx corruption was 640x200 which is quite useless since the aspect ratio goes bonkers. So I ended opening up a 640x480 WB display and play Ultima VII in a custom 424x265 res window. A nice game really

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)