Learning resources after website documentation

Hi,

I read the whole documentation section that had Introduction, Vectors intro etc. about oF and started doing the examples.

I was trying out the meshFromCamera example and the _setup()_ function had the something to which I didn’t come across anywhere in the documentation.
For eg: I noticed ‘glEnable(GL_DEPTH_TEST);

Similarly, in other examples as well, there are certain number of things that I didn’t come across, such as

ofSetVerticalSync(true);
ofEnableNormalizedTexCoords();
GL_DEPTH_TEST etc.

I wanted to ask about the the way I should go further in depth about normals, transform, rotation, modes, etc. etc. after I have read all this preliminary documentation on the website. The documentation although might be listing these functions, but the prototypes alone can’t give me an understanding of orientation, perspective, frustum etc.
Is there something that I missing on the website that I should be going through to get better at this and grab the concepts in depth?