The Ur-Quan Masters Discussion Forum

The Ur-Quan Masters Re-Release => Technical Issues => Topic started by: slylandroid on May 14, 2009, 10:18:03 pm

Title: Running in full screen mode cuts off the sides
Post by: slylandroid on May 14, 2009, 10:18:03 pm
When I run "uqm -f" to run it in full screen mode, a little bit of the left and right sides get cut off. 

Here are some photos to show you what I mean:

The sides do not get cut off if I just run uqm.exe without the "-f" option.

Anyone else have this problem?  I am running the latest 0.6.2 on Windows XP.

Title: Re: Running in full screen mode cuts off the sides
Post by: meep-eep on May 14, 2009, 11:59:43 pm
UQM switches video mode when you switch to full screen. Each video mode may require different calibration of your monitor. Try playing with the monitor's settings a bit. It's also possible that your video card came with a program which can adjust the signal that the video card sends to the monitor. (It's all a matter of timing, I think.)

Title: Re: Running in full screen mode cuts off the sides
Post by: Novus on May 15, 2009, 09:43:37 am
If your monitor is connected using a VGA cable (or a similar analogue connection), you will need to adjust the image size manually for each screen mode. Fullscreen games under Windows almost always use a different screen mode than the desktop; even if you select the same resolution, games often use a lower refresh rate.

The signalling protocol for VGA was designed for CRT monitors. Essentially, each row of the image is transmitted in sequence from top to bottom with sync pulses between the rows and at the end of the image to reset the horizontal and vertical position respectively. Early CRTs could not, for several reasons mostly connected to the fact that a precisely controlled voltage is needed to deflect the electron beam to the right place, reliably maintain image size and were therefore either designed to extend the image past the edge of the tube to ensure that no black borders can be seen (as on TV) or leave a border to ensure that no part of the image is cut off (computers and some video production equipment). The sync pulses in a VGA (or a TV) signal serve to tell the monitor that it should prepare for the next line or frame, but not when it starts, since that information is hard to use on a CRT. Later CRTs are more stable and allow the user to adjust the image size and position manually to fill the tube without cutting off part of the image. PC monitors can usually keep track of about a dozen resolutions and identify them by the sync frequencies.

LCD monitors (and projectors) have no problems with placing stuff in the right place on the screen since each pixel is a separate element connected to a controller, sort of like a memory cell in a RAM chip. Unfortunately, since the VGA signal does not clearly indicate where each row starts and which row is the first to actually contain data, LCD monitors (after roughly guessing the resolution from the sync pulses) typically have to guess where the signal starts and ends. Also, LCD monitors must guess where each pixel starts and ends. This is typically done by examining the image itself. If the image used for guessing does not represent a full screen, parts of the image may be cut off. Also, the resolution (especially the horizontal resolution) may be incorrectly detected.

Most LCD displays have an automatic adjustment feature that can fix your problem; press a button on the monitor and the currently displayed image is used to detect the resolution. I suggest you do this while in the main game, as it fills the screen completely. Consult your monitor documentation to find out which button to push. If this feature does not exist or work, you can use the manual geometry settings on the monitor (again, RTFM). I advise adjusting the monitor rather than the video adapter, since the monitor controls are easier to find and changing the signal timing may cause the monitor to think the resolution has changed and reset itself (neatly undoing any adjustment you've done).

Using DVI or some other digital connection to connect your LCD monitor avoids this problem entirely, as the beginning and end of each line and frame are clearly marked; the image transmitted by the graphics adapter will never be cut off and (assuming the resolution of the signal matches that of the display or scaling is used to scale the input signal to fill the display) will always fill the display. Additionally, a lot of analogue noise is avoided and pixels in the input signal can trivially be matched to real pixels. If your computer and monitor both support DVI, replacing your VGA cable with a DVI cable will eliminate the need for fiddling with image geometry settings and may improve image quality noticeably.

I just realised I've written a huge essay where a simple "push the auto-adjust button" would have sufficed. ::)

Title: Re: Running in full screen mode cuts off the sides
Post by: meep-eep on May 15, 2009, 12:46:15 pm
Additionally, a lot of analogue noise is avoided
As I understand it, there is no error-correction in the video signal, so digital does not necessarilly mean better quality than analogue, and a lot will depend on the quality of the cable connecting the monitor to the PC.

Title: Re: Running in full screen mode cuts off the sides
Post by: slylandroid on May 15, 2009, 11:30:15 pm
Thanks, the auto adjustment worked!