Taking resolution into considreation.. pc 2d games in c++.

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3 comments, last by L. Spiro 11 years, 6 months ago
The past games I have made, I usually focused on a single resolution and programmed my game accordingly. Whenever I changed the resolution, certain things were out of place and random bugs began to pop up. My question is, should I program my future games taking into consideration all resolution settings I want avaialble for the game, or is there some "auto-adjust" trick in doing this. I program 2d using c++. If anyone can point me in the right direction.. a book or url or any useful resource, would be much appreciated!

Thanks,
EdoMan
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There is an 'auto-adjust'. But you have to program it. ;)

First you have to think about your game, and how it works, and how it needs to look. Especially with 2D.

Can your game function in any aspect ratio, or do you need it fixed?
Can you draw more vertically or horizontally, or does it ruin the play-ability of the game?

Depending on these answers, there are different solutions.

If your game can draw more without ruining anything (unfair advantage, seeing more than intended, etc...), then you can just draw more of your game.

If not, then have a background image, and draw your game onto a render target that is the correct aspect ratio. Then draw the render target onto the background. This way, you can fit a 4:3 game on a 4:3 screen, and a 16:9 screen at the same time. This is how older games often get ported over to newer machines.

eg:

http://image.gamespotcdn.net/gamespot/images/2007/102/reviews/937627_20070413_screen001.jpg
http://image.jeuxvideo.com/images/p3/s/e/sega-mega-drive-ultimate-collection-playstation-3-ps3-043.jpg
http://3.bp.blogspot.com/_kGAOBLrWIr4/S9LKu7EzEfI/AAAAAAAABXA/aDl9Ov1jY_M/s1600/FFDI_FF_08_CABINET_MONITOR.jpg

You can also scale your finished render target to the screen size when you draw it, but that will make things look really bad. Sprites don't scale well when they go out of aspect ratio.
c++ doesn't do graphics. It depends on what libraries or whatnot you use to do your graphics.

When you change your resolution, generally some kind of event is triggered carrying information about the new resolution. You then respond to that event by changing your layout to appropriately deal with the change. Do you show more? Do you scale up? Do you do neither and paint it on top of a background?

A good way to deal with variable resolutions might be to use relative screen space coordinates instead of absolute pixel coordinates. For instance, x=0 would be the leftmost side of the window, x=0.5 would be the middle, and x=1 would be the rightmost edge. This would make your image always fill the screen, but as the above poster mentioned, you'd have distortion when the aspect ratio changed. You could then worry about detecting and correcting that distortion.

But in all, exactly how you do it is really dependent on what tools you are using to get anything to show up on the screen at all.
Not sure what those random bugs would be, but just to get things straight you should never use any 'screen resolution'-variable to calculate anything but stuff related to the screen. Random bugs will definitely appear once you use SCREEN_WIDTH to calculate the speed of your spaceship... When I was new to game development I did some nasty stuff with physics calculation depending on screen-variables, resulting in different situations depending on the players resolution.

If you don't understand the stuff written here, please sharpen your C++ skills.

This largely depends on your needs.

For example, a UI just generally needs to “stick” to the sides of the screen. As the screen changes resolution, things stuck to the right side move over, staying X pixels away from the right side of the screen. The UI images don’t usually grow.

On the other hand you probably want to expose only a fixed amount of your 2D world regardless of the resolution. For example, regardless of the resolution, the player can see only 10 tiles vertically.


For these things, you have to scale your visual game world up and down based on resolution.
One way was mentioned already. Use a 0-1 system such that 0 is the top and 1 is the bottom. Don’t do this for left and right; just keep track of the top and bottom for ratio reasons, and blacken out any extra detail to the left/right that you consider should not be visible within your world.


L. Spiro

I restore Nintendo 64 video-game OST’s into HD! https://www.youtube.com/channel/UCCtX_wedtZ5BoyQBXEhnVZw/playlists?view=1&sort=lad&flow=grid

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