Resize game by height only

[Alphapage]

Hello,

 

I'm designing my game using a 5000x1280 world without tilemap.

For example, when the resolution is 960x640, I want to scale to 2500x640 (ie world*0.5) and display only 960x640 without showing 1540px left in width.

 

I tried different ways even with camera too which I don't really need, but I always get my whole world without hidden part.

 

Thanks in advance for your help.