How to change size of the camera depending on the aspect ratio?

Hi all,

I need a help about this algorithm. I need to change the size of the camera, which is orthographic, depending on the players' aspect ratios. I designed my game for the aspect ratio of 16:9. When someone who has the aspect ratio of 18:9 for example, I need to change the size of the camera; so that the player will see the area like a player who has the aspect ratio of 16:9 (or as close as possible).

There are some other aspect ratios like 21:9, 4:3 (tablets) etc. The algorithm should be make the FOV like 16:9. It should increase the size if necessary (4:3 for example). A code example would be great for this.

 

If it is just UI you can use the AspectRatioFitter to control the UI shape, and select Fit Inside Parent.

For the actual camera, if you like you can black-band the extra shown area top and bottom or side to side.

Or you can change the .rect of the camera, but then you need a second camera behind it to avoid getting dead pixels at the undrawn area.

The orthographicSize maps (in Unity) to half the height of the screen, as seen here:

https://docs.unity3d.com/ScriptReference/Camera-orthographicSize.html

so by default a camera with a (0,0,1,1) cliprect will fill the screen laterally however much is necessary.

 

If you just want to change the size/shape of the camera so that it fills the available screen, I'm reasonably sure Unity already does that by default.

Are you trying to get letter-boxing, where it shrinks down the 16:9 image to fit inside of whatever screen you actually have? (That seems to be what Kurt-Dekker is assuming you want.)

Not entirely clear what you mean by "make the FOV like 16:9".

 

I'm not talking about UI. As it can be seen from the images, 16:9 cover that much area of 2K sprite (red area). For 21:9, it exceeds the sprite. To be able to fit 21:9 on the screen, I need to change the camera size. In this example, the camera size is 5. If the aspect ratio is 21:9. the size of 4 looks okay. I need an algorithm to make this automatically. It should increase the size if necessary. As it can be seen, for 4:3, the size must increase.

There is also another thing to be consider, it shouldn't exceed the top and the bottom of the sprite as well.

 

I have a similar problem where changing the aspect ratio from 16:9 to 16:10 will hide elements of my fight scene on the left and right sides and I am struggling to find a solution to automatically change my camera size so that I can see all the elements of the scene.

 

Me also. So glad someone resurrected this old thread

 

If someone find this thread in the future and need a quick solution for this case <3

This is a tiny script you can put on your camera, it will resize the camera rect to fit a given targetAspectRatio.

Code (CSharp):

1. [RequireComponent(typeof(Camera))][ExecuteAlways]
2. public class AspectRatioCameraFitter : MonoBehaviour
3. {
4.     [SerializeField] private Camera cam;
5.    
6.     private readonly Vector2 targetAspectRatio = new(16,9);
7.     private readonly Vector2 rectCenter = new(0.5f, 0.5f);
8.  
9.     private Vector2 lastResolution;
10.  
11.     private void OnValidate()
12.     {
13.         cam ??= GetComponent<Camera>();
14.     }
15.  
16.     public void LateUpdate()
17.     {
18.         var currentScreenResolution = new Vector2(Screen.width, Screen.height);
19.  
20.         // Don't run all the calculations if the screen resolution has not changed
21.         if (lastResolution != currentScreenResolution)
22.         {
23.             CalculateCameraRect(currentScreenResolution);
24.         }
25.  
26.         lastResolution = currentScreenResolution;
27.     }
28.  
29.     private void CalculateCameraRect(Vector2 currentScreenResolution)
30.     {
31.         var normalizedAspectRatio = targetAspectRatio / currentScreenResolution;
32.         var size = normalizedAspectRatio / Mathf.Max(normalizedAspectRatio.x, normalizedAspectRatio.y);
33.         cam.rect = new Rect(default, size) { center = rectCenter };
34.     }
35. }

 

Fixed the Vector2 declaration
Thanks this worked like a charm!