# Why do games only allow certain resolutions?

Only a few games have resizable windows when running in full screen mode. All others have a finite fixed set of allowed resolutions. But why? I see some reasons, but none of them seems to be that important to me that would justify such a user-unfriendly feature.

Example

Let's use Dark Souls II, because it's the first I can think of. The allowed resolutions are:

800x450
1024x576
1152x648
1280x720
1440x810
1600x900
1680x945
1920x1080


What is the reason to not allow the resolutions 800x451, 800x452, ..., 801x450, 801x451, ...? What it I think can't be:

• The UI. If we keep minimum and maximum window sizes as limitations, the only issue I can see here is with settings with a weird aspect ratio (1920x450, 800x1080). Otherwise, there shouldn't be any problems with free scaling between the resolutions.
• Camera, Viewport. Same as above.
• I would think part of it has to do with the layout of 2d elements on the screen. If you allow the user to freely resize the screen then the elements could overlap. – default Jun 19 '17 at 13:24
• Also, the 2d elements are often textures that are designed to be the right size for a certain screen resolution. If the user arbitrarily blows up the screen size, those textures will stretch and look bad. Instead, there are different textures for each supported resolution. – default Jun 19 '17 at 13:30
• This question is probably more appropriate for gamedev.stackexchange.com. See gamedev.stackexchange.com/a/125316/26734 – default Jun 19 '17 at 13:34
• Not quite enough info for an answer, but we query the driver to ask for what resolutions will work in full screen mode. The specific list of resolutions you give in dark souls 2 will vary from machine to machine. There are hardware and software (driver) limitations to what is available. – Alan Wolfe Jun 19 '17 at 14:14
• If you find the linked answer unsatisfying, you might be more likely to get the answer you seek if you edit the question to explain why you are not satisfied with the reasons given. That way you can avoid getting the same answer here. – trichoplax Jun 19 '17 at 18:25

Note that in your Dark Souls example, all the resolutions listed are the exact same aspect ratio. So the question is, why doesn't it support arbitrary aspect ratios?

The answer is that it costs time and effort to support arbitrary aspect ratios, and if that money spent doesn't translate to increased profit, then it doesn't make sense to do.

• This answer covers the 2d layout issues, which includes extra time and effort to create a versatile layout that can be resized so that elements do not overlap, stretch, or pixelate in an undesired manner, and that the overal UI maintains the best user experience.

• The developer would have to ensure that the window doesn't get too large or too small. Does it make the game any better if the user can drag the window size to be smaller than 800 x 450? probably not.

• you have to define the behavior of the camera when the aspect ratio changes.

For example, take the following scene:

If we allow the user to change the horizontal size, we can decide to "zoom out" horizontally so that the same area still shows up horzontally but now we can see more vertically.

Or, instead, we can keep the same zoom level but just clip the viewing area more:

Note, that if you don't specifically handle the changing aspect ratio, the default graphics pipeline behavior will be to stretch the image:

These decisions take time and effort to design, code and test, but management has to decide if it actually makes the user experience better enough to be worth the time. Apparently, most games have decided its not worth the effort. I'd even go further and suggest that allowing users to screw up the best layout of the game is a bad feature.

• Interesting point. Does this mean Dark Souls will run distorted on screens with different aspect ratios (e. g. an old 800x600)? I think the fact that they all have the same ratio might be due to what @Alan Wolfe said in the comments, that these are only those supported by my hardware on full screen mode. – piegames Jun 20 '17 at 7:57
• As a specific example, in the 2d game slither.io there is a max distance you can see. In portrait, you can see this distance vertically, with your horizontal view restricted. In landscape, you can see this distance horizontally, with your vertical view restricted. If you resize the window to be perfectly square, then you can see the max distance both vertically and horizontally, giving a significant advantage over other players. In addition to the time and money required to adjust to different aspect ratios, it can also become a potentially undesirable meta game. – trichoplax Jun 20 '17 at 11:50