Game Optimization for Multiple Devices

Conifer_Apps

I'm a little bit of a newbie, and I have a few questions pertaining to screen optimization. So far, I have tested my app on 1 device, the iPhone 5, and it works great. When I test my game on a 3.5 inch iPhone or an Android phone, what will happen in terms of cropping, scaling, and pushing the actors in? Can I specify different scenes for different devices? In my game I also use a random "spawn actor" attribute along the x axis to make actors fall from the sky. Is there any way to dynamically update this equation's minimum and maximum values to fit the screen size? The minimum and maximum values are the iPhone's screen width plus and minus ten pixels so the actors don't get cut off on the sides. Thanks so much for your your help!