For basics I would suggest
*these aren't OpenGL books, they just use OpenGL to teach rudimentary CG concepts
To be proficient in computer graphics or even to understand the basics, a decent amount of mathematical concepts needs to be grasped; it requires a decent understanding of trigonometry and linear algebra. For this I recommend
- Vector math tutorial for 3D Computer Graphics is by far the best resource for learning vectors and matrices. It is also interactive in that at the end of each section there's a test question to verify and seal the understanding of that topic.
Out of these math books, the most intuitive is the first with lot of funny anecdotes in between, the last is for hard core math fanatics (if you're afraid of symbol vomit, steer clear of it), although it's a good book for experienced CG programmers who need a reference. The one in between is really good in that it details out somethings which the other two (or many books for that matter) omit, and in the spectrum of intuitiveness and hard core math it's in between.
The reason I didn't suggest Real-Time Rendering is that it's not more of a "hands-on, get your hands dirty" CG book; it's a broad survey of techniques used in the industry than on fundamentals of CG and more of theory than workouts.