OpenGL 4.1(?) under Mavericks

Question

I've just upgraded my MacBook Pro to Mavericks (MacOS 10.9), including Xcode. According to Apple's "OpenGL Capabilities Table", this version has support for OpenGL 4.1, but a call to glGetString(GL_VERSION) returns "1.2" and my GLSL 3.30 shader, which begins with "#version 330" refuses to load, saying that version is not supported. Do I need to do something to Mavericks to enable 4.1 support?

Accepted Answer

When you request your pixel format using one of the lower-level APIs on OS X, you need to add the following to your attribute list in order to use a core profile:

CGL:

```
  kCGLPFAOpenGLProfile,     kCGLOGLPVersion_3_2_Core
```

NSOpenGL:

```
  NSOpenGLPFAOpenGLProfile, NSOpenGLProfileVersion3_2Core
```

Now, while the particular constant is named ...`3_2Core`, what it actually means is request a context that removes all deprecated features and supports at least OpenGL 3.2 (a core profile, in other words). You can get a 4.1 or 3.3 context using this same constant; in all honesty, including an actual version number in the constant was probably a poor choice.

If you do not specify this when you request your pixel format, OS X will give you `kCGLOGLPVersion_Legacy` or `NSOpenGLProfileVersionLegacy` respectively. And this will limit you to OpenGL 2.1 functionality.

If you are using a higher-level framework, then you will need to consult your API reference. However, be aware that on OS X you must have a core profile context to access anything newer than OpenGL 2.1.

OpenGL 4.1(?) under Mavericks

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