c++ - From quaternions to OpenGL rotations

Question

I have an object which I want to rotate via keys. The object should yaw, pitch and roll. After trying a lot, I figured out that glRotate has its limitations and it won't be possible to implement something like that with that function.

I've researched a bit and found out about quaternion-based rotation. It would be also possible to rotate via a rotation matrix, but almost everyone describes the quaternions as the best ever.

I have read about the quaternions and understood them fairly well, but how to implement them in my OpenGL program is still a mystery. Does anyone know a small example? Not how to implement the quaternion class but how to use it. I don't get how to put the things together.

Answer 1

You can easily build rotation matrices out of unit quaternions.

Given a unit quaternion a + bi + cj + dk, you can build the following 3x3 matrix:

Add the last line and column taken from the identity 4x4 matrix, glMultMatrix and you're done :)