Cocoa

I've been invited to give a talk at the SecondConf developer conference in Chicago, and I'm writing this to accompany it. I'll be talking about using the GPU to accelerate processing of video on Mac and iOS. The slides for this talk are available here. The source code samples used in this talk will be linked throughout this article. Additionally, I'll refer to the course I teach on advanced iPhone development, which can be found on iTunes U here.

Read on for more on using the GPU to accelerate processing of video.

The videos of the Advanced iPhone Development class I taught this past semester at the Madison Area Technical College are now available for free on iTunes U.  These videos amount to over 35 hours of HD content, covering more advanced iPhone development topics such as Core Animation, multithreading, Quartz 2-D drawing, and OpenGL ES.  The course notes that accompany the class are available for download here in VoodooPad format, or for viewing here in HTML.  Links to all sample applications used for the class are present in the notes.

Read on for more about the structure and presentation of the course.

Chicago hosted a satellite location for iPadDevCamp this weekend, and I had just as much fun as the iPhoneDevCamp I attended there two years ago. I had the privilege of speaking about Core Animation there, a talk where I crammed too much information into a one-hour space. My Keynote presentation is available for download here. The source code for the sample applications I showed off, NanoSpores for iPad and ReplicatorDemo for iPad, is also available for download.

I had also referenced my Advanced iPhone Application Development class for MATC. The final course notes for that are available for download here in VoodooPad format. UPDATE (6/29/2010): The final video for my class on Core Animation can now be found as part of my class on iTunes U.

Thanks for organizing the event go to David Kinney, who pulled the entire thing together despite having a busted MacBook Pro. He proved that the iPad really can be a work device. It was also extremely generous of TechNexus to allow us to use their very nice facilities for the weekend.

I've spent some time recently with DTrace, a performance analysis and debugging framework that ships on every Mac running Leopard. It's an extremely powerful framework that many Cocoa programmers disregard due to its apparent complexity.

I found that DTrace is actually reasonably easy to use, and have collected my experiences with it in a two-part article. The good people at MacResearch have published the two parts here and here. I invite you to check them out and hopefully learn a new way to tune your Mac or iPhone applications.

We're coming up on Apple's Worldwide Developer Conference (WWDC) once again, and I'll be there like I was last year. I'm looking forward to meeting all the people I've been introduced to online since I launched my little software company last year.

One other exciting element to this year's WWDC is the fact that Apple is hosting a code-a-thon onsite for a new open source framework called Core Plot. I'll be one of the coordinators of this framework, so if you're there at the conference you can probably find me in the Core Plot room. I'll be the one with the red hair wearing a black Sunset Lake Software T-shirt.

Read on for more about Core Plot.

We will be having another meeting of the Madison, WI CocoaHeads group tomorrow, March 24th, at 6:30 PM on the UW-Madison campus. We'll be in the Computer Sciences Building, room CS 1240 once again.

I'll be talking again, but this time it will be a more focused presentation on Core Animation and all the neat stuff you can do with it. It's been a little while since the last meeting, due to spring break, but I hope to have the same large group as last time.

We had a good turnout at the inaugural CocoaHeads meeting in Madison, WI last night (Maurice Cheeks snapped a photo of the event). The general theme was about getting started with Cocoa development on the iPhone. I mentioned some resources for this during the talk, and by request I'd like to list those here.

Read on for the list of Cocoa development resources.

Based on local interest, my coworker, Pete Johnson, has started a chapter of CocoaHeads to be based in Madison, WI. I'll be helping out as a speaker and organizer for the group.

Our first meeting will be on February 12th at 6:30 PM on the UW-Madison campus. We'll be in the Computer Sciences Building, room CS 1240. More details can be found here.

Read on for more about this first meeting.

I've been doing a lot of work with Core Animation lately during development of my next iPhone application, and I came across an interesting way to optimize OpenGL ES rendering that I thought I'd share. This small improvement yielded a 14-25% increase in the triangles per second I was able to push in Molecules.

Read on for more about this optimization.

UPDATE 2: Perspective rendering has been added: see below for the details.
UPDATE: 3-D scaling using pinch gestures has been added: see below for the details.

Recently, Bill Dudney posted a sample iPhone application that used Core Animation and a concept called a trackball to rotate an object in 3-D space using a finger as input. I actually use a different method of rotation within Molecules, so I thought I'd modify his sample to use that rotation.

That modified example iPhone application can be downloaded here.

Read on for more detail on this rotation technique