cyclone3d wrote:I need a list of some games that have non-standard resolutions to make sure that it will work properly with everything I can throw at it.
Normally games use standard resolution timings even if they make the visible area smaller or larger than by default.
As the first VGA monitors were "fixed frequency" type, they really work with singe line rate of about 31.46kHz, while frame rate can change between 60 and 70Hz (maybe down to 50 if memory serves). It means the horizontal scanning speed cannot be changed (except within tolerance), but there can be variable amount of total lines per frame to get down to wanted vertical frame rate, usually 70 or 60 Hz. Another thing that can be changed is the vertical scanning speed to fit either 350, 400 or 480 visible lines on screen, and that is set with sync polarity. There are rumours of even damaging monitors by changing the H/V timings, most likely multisync monitors can handle non-standard timings properly.
Therefore, no matter how many active or visible pixels or lines a game uses, they for the most part adhere to the strict timing limits so that they work on any standard VGA monitor and VGA card. As the image is normally underscanned to fit the screen, a game can within limits of monitor borders and VGA registers make the visible area wider or narrower by changing the number of active pixels drawn per line, but it does not change the line frequency.
As VGA card has two selectable pixel clocks, that gives two possibilities for how many pixels there will be per line to make the line rate constant.
25.175MHz clock can fit nominal 640 pixels on screen by default, and by doubling the pixels (halving the pixel load clock) it gives the 320 pixel modes.
28.322MHz clock can fit nominal 720 pixels on screen by default, and by doubling the pixels (halving the pixel load clock) it gives the 360 pixel modes.
And as monitor can draw nominally only 350, 400 or 480 lines visible, the other modes can be made by replicating lines, i.e all 200-line and 240-line modes are really scanline doubled 400 and 480 line modes. Normally 350 and 400 line modes are 70Hz modes and 480 line modes are 60Hz on standard VGA.
Unless there are bugs or deliberate changing of video timings for some reason, weird resolutions should just be using standard timings, but are just using more or less pixels or lines that are normally used in the visible area. Because the monitor does not know this, therefore modern LCDs and converter boxes might not show properly the areas that extend beyond standard visible area.
So, for example, 320x200, 320x400, 360x200, 360x400, 640x200, 640x400, 720x200, 720x400 should all be identical 70Hz formats from the monitors perspective.
Same goes with 320x240, 320x480, 360x240, 360x480, 640x240, 640x480, 720x240, 720x480, these should be all identical 60Hz formats to the monitor as well.
Syndicate uses standard 640x480 resolution timing but reconfigures the VGA card to only draw 400 lines of video memory data and to start drawing those 40 lines later than by default to get those 400 lines centered on 480-line screen.