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DOSBox scaler settings?

Posted: Fri Sep 03, 2010 12:22 am
by audiodane
This may not be the right place for this, but since it directly applies to me playing SQ right now, this is where I've chosen to put it. :)

I've noticed the default DOSBox settings are in some areas quite different than the SQ Collections Installer DOSBox settings. Primarily the display settings are different. Below are two snapshots comparing the two differences-- hard to tell unless you can really "flip" quickly between the two...

I guess my questions are, which are closer to the original aspect ratio? I seem to recall reading somewhere that old CRT's had non-square pixels, and the resolution was 320x200, which doesn't equally scale to 800x600 (it would be more like 800x500).

I guess I'm trying to figure out how to get DOSBox to best represent the original image, scaled to today's screens, while also taking into consideration today's square pixel size...

sq1ega-1.gif settings:
fullscreen=false
fulldouble=false
fullresolution=original
windowresolution=original
output=surface
machine=svga_s3
frameskip=0
aspect=false
scaler=normal

sq1ega-2.gif settings:
output= overlay
fullresolution=0x0
windowresolution= 800x600
fullscreen= false
autolock= false
aspect=true
scaler= normal

The bolded items for sq1ega-2 are what I'm wondering about...

Is the first image squished, or is the second image stretched, compared to what it "should" be?

thanks!
..dane

edit: the CD collections installer actually puts the scaler to "normal3x" I believe-- I changed it to get a closer image-size before aspect-preserved-scaling in irfanview.

Re: DOSBox scaler settings?

Posted: Fri Sep 03, 2010 1:22 am
by MusicallyInspired
Setting aspect ratio correction to "TRUE" gives the more accurate representation of the rectangular pixel resolution of the original graphics. Your second screenshot is the correct way it should be displayed.

320x200 resolutions on today's displays would result in a widescreen 16:9 aspect ratio rather than the 320x240 4:3 aspect ratio resolution. But originally 320x200 on CRT monitors had rectangular pixels which "stretched" the image to a 4:3 ratio. As a result graphics for most games at the time (including all Sierra games in 320x200) were created with rectangular pixels in mind and so objects that should be perfectly circular appear as a wide ellipse on modern displays if aspect ratio correction isn't set.

Re: DOSBox scaler settings?

Posted: Fri Sep 03, 2010 1:40 am
by audiodane
awesome answer-- thanks!

Need I ask the difference of "overlay" and other display settings and their influence to the game, or should I just stop asking questions and get on with using Collector's installer settings? :oops:

..dane

Re: DOSBox scaler settings?

Posted: Fri Sep 03, 2010 1:54 am
by Collector
Mostly what is in the installer conf files are the settings that I have chosen that are different from the defaults. DOSBox will use the defaults for everything else. I do include a couple settings that are the same as the defaults to make it easier for those that may wish to change it, such as the location of the captures folder. The config tool can change a couple of the custom settings back to defaults. Below are the reasons that I chose that you highlighted.

The aspect=true is for aspect correction in Windowed mode on modern monitors.

The windowresolution=800x600 will give a 3x sized window, even if a VESA driver has been selected (depending on the output mode chosen).

The fullresolution=0x0 will prevent screen stretching with full screen, even if displayed on a wide screen monitor.

The output=overlay is to prevent pallet corruption in full screen. I haven't checked if this is still an issue with 0.74, although I believe that this is more of a SDL issue than a DOSBox issue. Also it allows scaling of VESA games where surface output does not.

Re: DOSBox scaler settings?

Posted: Fri Sep 03, 2010 2:31 am
by Qbix
colour corruption should be fixed in 0.74. however the scaling for the windowresolution requires
an output that isn't surface.

Re: DOSBox scaler settings?

Posted: Fri Sep 03, 2010 11:36 am
by MusicallyInspired
Aspect correction works in fullscreen too.

Re: DOSBox scaler settings?

Posted: Fri Sep 03, 2010 11:57 am
by jujigatame
Collector wrote:Mostly what is in the installer conf files are the settings that I have chosen that are different from the defaults. DOSBox will use the defaults for everything else. I do include a couple settings that are the same as the defaults to make it easier for those that may wish to change it, such as the location of the captures folder. The config tool can change a couple of the custom settings back to defaults. Below are the reasons that I chose that you highlighted.

The aspect=true is for aspect correction in Windowed mode on modern monitors.

The windowresolution=800x600 will give a 3x sized window, even if a VESA driver has been selected (depending on the output mode chosen).

The fullresolution=0x0 will prevent screen stretching with full screen, even if displayed on a wide screen monitor.

The output=overlay is to prevent pallet corruption in full screen. I haven't checked if this is still an issue with 0.74, although I believe that this is more of a SDL issue than a DOSBox issue. Also it allows scaling of VESA games where surface output does not.
So the "fullresolution=0x0" will cause full-screen mode to scale to the original ratio? I actually just got a widescreen monitor a few months ago and have been plagued by the stretchy screen issue. Do black bars cover the left and right or does it just leave your desktop in the background?

Re: DOSBox scaler settings?

Posted: Fri Sep 03, 2010 1:37 pm
by Collector
With 0x0 the screen will be "Pillar Boxed", the reverse of Letter Boxed.

Re: DOSBox scaler settings?

Posted: Fri Sep 03, 2010 5:47 pm
by audiodane
Thanks for such thorough explanations. Much appreciated!

Re: DOSBox scaler settings?

Posted: Sat Sep 04, 2010 3:29 am
by Qbix
fullresolution=0x0 means use your current desktop resolution on windows. 1024x768 on non-windows systems.

Re: DOSBox scaler settings?

Posted: Sat Sep 04, 2010 11:00 am
by audiodane
Qbix wrote:fullresolution=0x0 means use your current desktop resolution on windows. 1024x768 on non-windows systems.
Sorry qbix, I don't understand what that means. I've seen that definition elsewhere. Is Collector's definition above ("The fullresolution=0x0 will prevent screen stretching with full screen, even if displayed on a wide screen monitor.") incorrect?

thanks!
..dane

Re: DOSBox scaler settings?

Posted: Sat Sep 04, 2010 2:35 pm
by Collector
Qbix is right (not surprisingly, as he is the author of DOSBox). It means that the resolution used when full screen will be the same as the resolution you you have set for your desktop. My mistake was based on a misunderstanding from before I had a widescreen monitor.

Re: DOSBox scaler settings?

Posted: Sat Sep 04, 2010 10:18 pm
by audiodane
Collector wrote:Qbix is right (not surprisingly, as he is the author of DOSBox). It means that the resolution used when full screen will be the same as the resolution you you have set for your desktop. My mistake was based on a misunderstanding from before I had a widescreen monitor.
So what does that mean-- that the aspect ratio correction will not apply in full-screen mode, or just that the native resolution will be that of your desktop, but that scaling and aspect ratio correction will still be applied?

thanks,
..dane

Re: DOSBox scaler settings?

Posted: Sat Sep 04, 2010 11:29 pm
by Collector
Just that the native resolution will be that of your desktop. Use aspect correction for full screen, too.

Re: DOSBox scaler settings?

Posted: Sat Sep 04, 2010 11:53 pm
by jujigatame
When I try fullresolution=0x0, I only see an small image in the center of the screen, with a huge black border on all sides. Is there something else I have to do to scale the image up to take up more of the screen?