PC, MAC Linux to iOS

Hi
Lets say I created a standard project (for PC, mac and Linux), when i go into build settings and want to switch to iOS platform (for iPad) do I need to change all of my coding or does the engine do it to change for the iOS platform?

Regards.

You won’t need to change all of your coding. What you will need to to is re-implement the user interface. On PC/Mac/Linux you presumably use keyboard and mouse. On the iOS you’ll need to use the Touch interface. That can be a lot of code changes, and a lot more logic changes. Also, your artwork might need to be changed, since the mobile GPUs are not like desktop/laptop GPUs.