Resolution and Aspect Ration Independent 2D Game Engine Design

[pstudio]

I think that in most games, keeping the same experience despite the resolution is crucial, so there goes either fixed resolution or scaling. Scaling has the problem that, oh well, it takes some time and must be done such way that the result is this likeable.

Showing more of the game world will work only for... how to say it? not much action-packed? games. I mean, yes, you can show more space in a shooter, but this will allow the player to see more, making the game easier for him. And if we are talking about multiplayer, perhaps... That is an absolute no-go, as it gives one player advantage over the other. Although this will work fairly for puzzle, or turn-based strategy games, where the gameplay is not affected by one's speed of reaction and ability to tonice things quickly.

My only other idea than showing more of the game world, in case of additional screen space, would be a bigger UI; possibly providing more detailed information (but rather not more information, in terms of quantity) and maybe some additional buffer/shortcut space.

I pretty much agree. I many games it's important to keep the same experience across resolutions and for that reason I'm not keen on just showing more of the game world. At least not without careful consideration. Different UIs for different resolutions could be a solution.

OpenGL is good in that you can scale the coordinates. For example if you use Ortho style drawing, you can do something like:

glLoadIdentity;
glScalef(ClientWidth/100, ClientHeight/100, 1);

And now your coordinates will be 100 x 100 regardless of window size. Any graphics drawn with these will at all times be drawn in full window area, and you don't need to care if it's actually 1024x768 or 640x480. But often times you don't want to do that, because fonts or certain graphics will bend and look bad. Still, it's much faster than drawing to a buffer and scale it.

I don't see this will solve the problem in an elegant way. The game will ultimately be designed for one resolution and the game will look distorted on other resolutions.

Thinking about aspect ratio is actually a move in the right direction, but you shouldn't really be thinking of aspect ratio per se, rather than the overall layout. My suggestion is the following.

First, try not to think of resolutions. Think of the screen layout and how many layouts you will support. If you have iPad, try to look at it vertically and horizontally.Try to imagine if iPad was shorter but longer (e.g. being a widescreen). Try to draw the organization layout on paper thinking where you will put your game's elements depending on the screen orientation and shape (e.g. closer to 4:3 or closer to 16:9).

Once you have the proper organization strategy, one important issue is how will you handle different DPI settings. For instance, you may want to include large icons and resize them to smaller versions on the fly to take advantage of high DPI displays and make the game look similar on different devices. Another alternative would be putting more elements with higher DPI settings, so instead of bigger icons, the user will see more of them. You can even try some hybrid approach as well.

If you plan your game's conceptual organization on different layouts (vertical/horizontal) and shapes (4:3, widescreen), properly handling different DPI settings, you will make the majority of your users happy. As you can see, this way you are not thinking of resolutions and aspect ratios, and you are not using vectors, procedural content and other stuff, which is not related here anyway. This is the best non-intrusive approach, which in many ways is enforced when you develop for iPhone/iPad, even though it perfectly applies to Windows/Mac OS systems.

In order to properly solve a problem, instead trying to fix the problem itself, you should change the conditions accordingly so the problem ceases to exist. You may want to check this article, which is more of philosophical nature, but still applies here.

I find this interesting. Right now I'm mostly thinking in classical 2d action games/platformer etc. where the spatial relations between game objects are important. As I see it the layouts will primarily describe different UI layouts. You can't change the game world presentation because this will result in different experinces of the game. The extra space gained using wider aspect ratios can mostly be used for HUD display and insignificant parts of the game world. Or do you disagree with this statement?

Regarding properly DPI handling. What do you think properly DPI handling means? I was thinking of using assets of a high resolution and then downscale. I know resolution doesn't equal DPI or PPI but we typically only use resolution in pixels when talking about graphics in computer games. Is it that important to think in DPI instead? I can imagine that you could possibly gain from increasing font size on high DPI screens but does this the mean you'll have to create layouts for different aspect ratios and different DPI?