GameKit bluetooth help

Question

Hi,

I'm trying to understand the basic steps required for a game I'm trying to make using GameKit for bluetooth connections. I only have 1 device, so I can't test out my ideas very easily - therefore, I'd really appreciate any help you could give.

The game involves a maximum of 2 players over bluetooth via GameKit and the only data to send/receive is a 'shot' which includes position and direction data only.

This is what I think should happen, I really just want someone to point out any mistakes I've made:

• The game starts by presenting a GKPeerPickerController with a connectionTypeMask of 'GKPeerPickerConnectionTypeNearby' and setting it's delegate to 'self'.

• The GKPeerPickerController delegate method 'peerPickerController:didConnectPeer:toSession:' is implemented and sets the sessions dataReceiveHandler to self. The peerID is added to an NSMutableArray which holds all peer IDs connected. (There should only be 1 peer connected at any time).

• To enforce only 1 peer connection per game the method 'session:didReceiveConnectionRequestFromPeer:' checks the 'count' property of the NSMutableArray which holds the connected peerIDs. If 'count'>0 then we respond by calling: 'denyConnectionFromPeer:' else, we call: 'acceptConnectionFromPeer:error:'

• To send a shot, the game calls: 'sendData:toPeers:withDataMode:error:'

• To receive shots, the game responds to: 'receiveData:fromPeer:inSession:context:'

Are there any steps missing? For example, if a user tries to connect to me before I connect to them, what will happen with my GKPeerPickerController? How do I know to dismiss it?

Please help! This is pretty urgent and without another iPhone/iPod I can't test...

Best Regards,

David

Answer 1

First off, if you want to test Bluetooth in Gamekit you really are going to need a 2nd device. If you're serious about your app, try and buy a cheap/refurbished iPhone or iPod Touch that will support GameKit Bluetooth (the oldest devices don't do it). I actually think you do even better with two Macs for testing, but if you don't already have a second one that's an expensive proposition.

What you've posted above is pretty much correct - actually using the PeerPicker is pretty straightforward and you should be able to get through it easily using Apple's docs. The problem is that in my experience, it's a bit janky. It might be because I'm using a 3GS and a 3G to test and they have different Bluetooth inside, but a lot of times I see weird things when the scenario you outlined occurred - "if a user tries to connect to me before I connect to them." In the end it typically still works, but not without a little overhead of waiting and perhaps the user having to repeat the process a time or two.