iPhone – Yellowtail
A week ago I got a shiny new iPhone. A few days later I got my Developer’s Certificate and the API. Two days after that, today, I’ve got the first app up and running!
It’s a port of Golan Levin’s Yellowtail with the small addition of multi-touch.
OF and Processing nerds read on
For the OF and processing nerdies out there, what’s actually interesting about this is that this is the beginning of a OF/processing style interactive graphics platform for the iPhone in which you can get by with 95% C++ and avoid writing your app in Objective C.
This two day old version supports multi-touch. I’m essentially treating each finger as if it were a different cursor. Instead of mousePressed(int x, int y) you get touchDown(int x, int y, int touch) where 'touch' tells you just which finger I’m talking about; they’re numbered in the order in which they appear (and you can have up to five at once!) For convenience there’s also a doubleTap(int x, int y, int touch) function.
Another feature is a C++ wrapper for OpenGL-ES textures and images (similar to ofImage and ofTexture). OpenGL-ES is a little nastier to write since it has to be efficient, and there’s a good 100+ lines of code just to draw a png into the screen. Also the only image format I could get to work is a PNG-24.
Also managed to figure out how to interpret “mach” kernel’s time to derive millis() which familiarly tells you how much time has passed since the app started.
There are a few other minor things like quick commands to show and hide the iPhone status bar (I’ve made it hidden by default) and to launch a URL (which quits your app and loads Safari).
The code is nasty as all get out right now, so no public download for now. I hope to have something to share pretty soon. Look out for Yellowtail on the App Store in the very near future!

I’m looking forward to see how this platform you are working on will be.
Cheers, chr
Out of curiosity, why would I not want to use Cocoa?/OBJ-C ?
OK, that is sweet, especially with the multitouch.
Yellowtail could make a interesting signature verifier since it records both shape and speed.
How about some variants? It would be interesting to see things bounce off each other. Or closed shapes stay in place. Or draw a circle (or any closed shape), and then things drawn *in* that circle stay within it. Call it YellowCell…
Anyway, looking forward to draining my battery soon.
Cool stuff. But I’ll also ask: Why not Obj-C?
vade & Zach,
You certainly could use Objective C instead of C++, there is no performance hit for choosing either one to my knowledge.
My personal benefit is that I am not very comfortable with writing Objective C, and C++ is more homey to me. Add on to that many of my previous apps that I’d like to port to the iPhone are in C++, there are tons of libraries available in C++ and to top if off there is a big community of interactive art hackers that I’m appealing to with this (openFrameworks).
You certainly could make this exact same thing without touching C++.
Perhaps the point is that the flexibility to choose between the languages (or mix them) lets me work the way I like!
Hey, this looks very cool! Have you come further with the release of the code? Would love to give it a look.
I gotta admit, I havent worked with C++ since college so I’m lost with all of the technical stuff but that video is pretty damn cool!
I have to admit – I don’t understand anything that you are saying….but I do understand that what you created it really, really cool and impressive. Is it up in the app store yet?
Thanks for the post, is that got me exactly where I needed to go.
Nice post having an excellent content,which are really helpful for a reader like me.Thanks for sharing this with us.Keep it up.Keep blogging.
I loved this application you showed in the video. Can you post the link where I can download it?
I too love the application shown in the video. However, all the programming talk got me confused. I assume the app was built with C++??
I’m looking forward to see how this platform you are working on will be.
Congratulations on your great work. Hopefully you will get all the respect you deserve for it.
I was just researching YellowTail for iPhone and I came across this post. It’s funny how you can look back to the developing stages of the app and see how much it has changed. I really enjoy playing with it with my family. Thanks for making such an awesome app!
Hey Kitchen,
It’s pretty crazy that you mention that. I love watching seeing things progress.. I’m a huge fan and so glad that this is available.
w00t!!
;D
Corey
Boy, you “lexis” guys get around. I don’t know if it’s explained but Yellowtail is an interactive software system for the gestural creation and performance of real-time abstract animation. Using a playful animated transformation of the user’s gesture, the software produces an ever-changing and responsive display of lively, worm-like textures.
You made an Iphone app in 2 days? Holy crap!
Where is the best place to learn how to program app for the I phone? Thanks for any help.
Congratulations on your work.
Amazing, realy it’s very useful information for all of us. Thanks for providing us this information
Amazing, this was exactly what i was searching for.
Love Yellowtail, fantastic port. Thanks for the news and video.
Yellowtail seem like a cool port, just get that phone fist…
Clare