iphone - How to create games with scrolling?

In games like city story or we farm how do they implement scrolling?

1. 
   
   

   To do scrolling using UIScrollView the EAGLView size has to be bigger. In those games EAGLView size look like more than 1024*1024. But there is limitation in viewport size in iphone devices(in 3G iphone max is 1024).

   
   


2. 
   

   I played those games in 3G iphone they are working fine.

   
   


3. 
   

   Any idea how they implemented their scrolling mechanism?

   
   

Answer

Well they don't use something like a UIScrollView, that's for sure. You would just move the camera over a stationary world or move the world under a stationary camera. I'm a little rusty on my GL, but I would guess you just push a new translation matrix before all your drawing.

For the actual dragging part, you would also implement that yourself. It would probably be something where you check to see if there was a certain amount of cursor/finger movement delta in a given amount of time to see if it's a "drag" or a "click". Or maybe you always drag unless the user clicks on a UI element or something like that. It really depends on the design of how you want that system to work.