Gold Challenge & Core Graphics


Anyone else having trouble with the Gold Challenge? I did the first 2 with no problems, but all I could get to work on the Gold was drawing the image, cropped to a circle. Is the Core Graphics framework just a difficult framework to grasp? On that same note, is all graphics programming this difficult? (OpenGL/ES, etc.).


Graphics programming is not difficult at all; however, you should learn the basics first before embarking on a major project.
You also need to know some linear algebra in order to manipulate points, vectors, matrices, etc; also a firm knowledge coordinate system transformation is a must.

You might want to check out: Quartz 2D Programming Guide.

Also on the language front, C++ is a must.


I’m good with algebra; I’ve taken everything up to applied calculus. I glanced at the quartz 2D guide but it just seemed so… stale. Even if I stick with Xcode & Cocoa Touch, I’d still need to learn C++?



Note that linear algebra and general algebra are two very different topics. If the phrase “matrix multiplication” doesn’t result in a Pavlovian reaction of some type, you haven’t taken linear algebra.

I’m a bit skeptical about C++ being a must, but I don’t do any graphics programming.


I’ve done matrix multiplication before… although I don’t remember enough of how it works to actually do it without reading up on it some more. I do remember, though, that I extremely disliked it.


You don’t really need C++ for toy projects, but it is a must for serious graphics programming.

As for Linear Algebra: Check out this excellent resource (probably the best): MIT OCW 18.06 Video Lectures (by Prof. Gilbert Strang): … pring-2010.

By the way, you should invest in learning C++ (In Xcode, you can even mix Objective-C and C++ code effortlessly.)


What kind of graphics can be done with C++ that can’t be done with C or objective C? At this point all I’m interested in learning is Quartz/Core Graphics & OpenGL ES.

Edit: Also, from a non-graphical standpoint, what benefit(s) would arise from developing Cocoa/Touch applications with (Objective)C++?