There are no CoglRenderer
or CoglContext
classes in the current vapi file for cogl-1.0
.
I don't think you can even initialize Cogl without these which I can oddly only find in the documentation for cogl-2.0.
https://developer.gnome.org/cogl-2.0-experimental/stable/
Since there doesn't seem to be any Vala example at all and not many C examples, it's difficult to ask your question.
You should probably ask the Cogl mailing-list.
Edit: Since your question was about Clutter + Cogl there is indeed a Vala example here: https://wiki.gnome.org/Projects/Vala/ClutterSamples
Edit2: There is a Hello World
tutorial using cogl-2.0 here: http://www.cogl3d.org/hello.html
As you can see Cogl is much more low level, when you use it standalone (without Clutter) you have to do a lot of setup code youreself (create drawing context, create a framebufer, create your drawing primitives, create a drawing pipeline, draw your primitives, etc.).
I don't know how Clutter works internally, but I think it does a lot of that work for you.
In any case it can't hurt if you learn some OpenGL first, since Cogl is a wrapper around OpenGL.
Edit3: This blog post shows how to integrate Cogle into Clutter: http://radialmind.blogspot.de/2012/02/cogl-or-opengl-for-3d-clutter-scenes.html
So this is how you jump out of the clutter loop: Define a custom actor. I did one in C, another example uses the C++ version. See also here. Define some properties that modify how things are rendered and some other general behavior. Override the paint loop. Save the matrices, define your own matrices, call your custom drawing code in 3D (has to be cogl!) and then put the matrices back as you found them.