iOS

There are 86 posts filed in iOS (this is page 10 of 18).

iSimulate: A Great Add-On For The iPhone Simulator

isimulateI just had a chance to check out iSimulate, a tool for iPhone developers created by Vimov. iSimulate is intended to complement the current iPhone simulator by adding most of the features a real iPhone has. In the spirit of full disclosure, Vimov sent me a promo code to try it out for free, but I only accepted it with the condition I could write my unfiltered impressions. So here we go.

iSimulate consists of two different parts: The iPhone app, which you need to purchase through the App Store, and a static library that you link with your program. Once your app is using the library, launching the iSimulate iPhone app lets you connect your device to your app and forward accelerometer, touch, and GPS events. In other words, most of the things the simulator doesn’t do natively.

iSimulate definitely passed my picky installation requirements with flying colors. I was afraid the installation would hook up with existing framework libraries, add new configurations, and in general mess up my system. Fortunately, hooking up the iSimulate library couldn’t be easier: Copy the provided .a library anywhere you want, link with it in your app (don’t forget the -ObjC linker flag), make sure you’re using the Core framework, and you’re good to go. That simple. That’s how I want external libraries to work.

You don’t even need to initialize anything. Just launch your app in the simulator, launch iSimulate on the iPhone and it detects your program running and lets you connect to it. The iPhone app itself even looks very pretty and polished. The overall package is definitely very professional-looking.

From there, any touch on the device is forwarded to the simulator. So you can finally do off-center multi touches, or two touches that happen at different times, or even 5-touch events (the max the iPhone support). The other big one is being able to tilt or shake your device and see the game react correctly on the simulator, which is would have been very handy when writing the accelerometer code to move flowers around in Flower Garden, but would almost be necessary when you’re making heavy use of accelerometer input for games like Sky Burger. Finally, it also claims to give you location information, but I didn’t have an app I could easily test it with.

Flowers affected by gravity on the simulator

Flowers affected by gravity on the simulator

Another situation where iSimulate is a life savior is when trying to capture a video of your game. If you rely on multi touch or accelerometer features, then your only options are to either hack in something yourself, or dig out a physical video camera and record it the old-fashioned way (which is surprisingly time consuming and creates less-than-ideal results). With iSimulate you can still use a desktop video capture software on the simulator and create a top-quality in a fraction of the time.

Not everything is perfect though. I thought the forwarding of touch events would be incredibly useful, until I realize I have no idea what I’m about to tap because the program is running on the simulator, not on the device. So I’m just making a guess about where my finger is going to land. It’s not even like a mouse cursor that you see where it’s going and then you click. You’re literally tapping blind hoping you touch what you wanted. That works with a static UI, but if you have moving elements you need to touch, you’re totally out of luck. I wonder if they could extend iSimulate to capture the image from the simulator and forward it to the iPhone. Even if they only refreshed the image a few times per second, that would be enough to make touch input a lot more friendly.

There’s another big problem with touch input though. From their docs page, iSimulate works great with OpenGL apps, but doesn’t work with the following UIKit controls: Keyboard, UIScrollView (including MKMapView), UIPickerView and UITableView. Wow! Apart from the keyboard one (no big deal, we have a real keyboard attached) the other ones are pretty major. I’m sure they have a good reason why, but I can’t imagine what that might be from my knowledge of how the touch even system works (anybody from Vimov care to comment on that?). Heck, I’d even be willing to add some extra code to my app to hook directly into iSimulate input events if it means it would work with those classes. Apart from that, I found one case in Flower Garden where iSimulate failed: Touching the bouquet tag to bring up the editing mode. It’s weird, it would let me touch-drag it to move it, but it wouldn’t go into editing mode.

The accelerometer input worked flawlessly, but here iSimulate has some competition from Accelerometer Simulator, an open-source app plus library to forward accelerometer data from the device to the app. It’s not nearly as slick as iSimulate, but it’s free, so that migth be a more attractive solution for some people.

Overall, is iSimulate worth the $32 price tag (it’s $15.99 at the moment)? I would say yes if you’re developing OpenGL iPhone games with heavy use of multi touch and accelerometer input and you’re planning on making money from them. In that case, you’re better off spending an hour of your time polishing the game (or taking a break from programming) and buying iSimulate. However, if you’re using UIKit objects or you just need accelerometer input, then you might be better off just using Accelerometer Simulator. If Vimov can fix the UIKit input and display the output of the simulator on the device, iSimulate would become an indispensable tool in every programmer’s toolbox.

Early Bird Registration Ending For Denver OpenGL Class And 360iDev

OpenGL_iPhoneFor those of you still on the fence about attending my iPhone OpenGL class in Denver, you should sign up before this Sunday if you want to get the super-combo deal. Right now you get a total combined discount of over $300 if you sign up both for the OpenGL class and the 360iDev conference. If you’re only interested in the OpenGL class, the early-bird registration ends next Friday, September 4th.

Obviously I’m biased when I say the class is going to be awesome (which it is), but I can also say with total honesty that 360iDev is an incredible conference. It’s very different from WWDC, but that’s what makes it so great: It has top-quality content and speakers, but it’s small and intimate, so you get to meet and hang out with all the other speakers and participants. It was at the first 360iDev conference back in March that I met Keith and Owen (among many other cool developers) in person for the first time and that’s how App Treasures was born.

So if you’re on the fence, I hope you give it a try. See you in Denver!

Handling App Store and LinkShare Links

One of the perks of being part of the App Treasures label is that we get some nice cross-promotion with an in-game view to display other titles in the label. This list is, of course, stored in our server and pulled in through a standard UIWebView. It links to other pages with details for each of our games, and a link to buy it directly from the App Store. Everything is really straightforward, except for the App Store link.

AppTreasuresWebView

By default, the UIWebView will try to open the App Store link itself, which results in an error. What we want to do instead is intercept the request and launch it directly with an NSURLConnection so the call can be redirected to the iPhone App Store app. The best place to implement this is in the -[UIWebViewDelegate webView:shouldStartLoadWithRequest:navigationType:] method:

- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType
{
    if ([[[request URL] host] isEqualToString:@"phobos.apple.com"])
    {
        NSURLConnection* conn = [[NSURLConnection alloc] initWithRequest:[NSURLRequest requestWithURL:[request URL]] delegate:self startImmediately:YES];
        [conn release];
        return NO;
    }
    return YES;
}

While we’re in the topic of links, I also recently added some LinkShare links to my apps. The 5% kickback for each purchase is nice, but the tracking capabilities it gives you is the real reason I wanted to use it. The way LinkShare works is by providing a custom URL that contains your referral ID to allow LinkShare to track the transaction. Unfortunately, unlike the Amazon referral program for example, LinkShare is a third party company and is not tied directly into the App Store. That means the links they provide go through click.linksynergy.com and then are redirected to the App Store. The result is that trying to follow one of those links from your app will result in Safari coming up, opening up a new page, shutting down, and then opening the App Store app. Not pretty!

Fortunately, there’s a workaround. Just like we did with the App Store links, we can open the LinkShare link directly with a NSURLConnection instead of letting Safari handle it. Then, once the link resolves to the forwarded one, we can open it directly with the App Store app:

- (IBAction)buyItNow
{
    NSString* link = @"http://click.linksynergy.com/fs-bin/click?........";
    NSURLConnection* conn = [[NSURLConnection alloc] initWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:link]] delegate:self startImmediately:YES];
    [conn release];    
}

- (NSURLRequest*)connection:(NSURLConnection*)connection willSendRequest:(NSURLRequest*)request redirectResponse:(NSURLResponse*)response
{
    m_iTunesURL = [response URL];
    return request;
}

- (void)connectionDidFinishLoading:(NSURLConnection*)connection
{
    [[UIApplication sharedApplication] openURL:m_iTunesURL];
}

Voila! The user goes directly to the App Store page, there are no annoying Safari transitions, and you still get the referral bonus.

Incidentally, most of this is already documented in an Apple Technical Q&A note, but it’s kind of hidden away and I think most people don’t know about it.

If you’re using LinkShare, you should also check out this post at Mobile Orchard. One of the things I learned there was the use of the &u1 parameter, which allows you to tag links with arbitrary information so you can track where purchases came from. Knowing where people are buying your app from is extremely helpful to know how to maximize sales!

[Edit: Sam Steele pointed me to the source code for the Last.fm app which handles all the URL redirects. Thanks!]

Environment Mapping Demo With OpenGL ES 1.1

CarI just finished creating a graphics demo for a chapter I’m writing for the book iPhone Advanced Projects edited by Dave Mark. In the chapter I go over a few different lighting techniques and go in detail on how to do masked environment mapping on an iPhone 3G with OpenGL ES 1.1.

The demo ended up looking pretty good, so I decided to upload a quick video showing the different lighting modes:

  • Diffuse texture only
  • Diffuse texture plus ambient and diffuse lighting
  • Diffuse texture plus ambient, diffuse, and specular lighting (as usually, per-vertex lighting looks pretty bad, even though this is a relatively high-poly model)
  • Fully reflective environment map (using the normal environment map technique)
  • Environment map added to the diffuse texture and lighting
  • Environment map with a reflection mask plus diffuse texture and lighting (two passes on an iPhone 3G–or one pass if you’re not using the diffuse alpha channel)

The chapter in the book will go in detail into each of those techniques, building up to the last one. Full source code will be included as well.

Some of these techniques will also be covered in my upcoming Two Day iPhone OpenGL Class organized in collaboration with Mobile Orchard.