1- Is it OK to use glRotatef with quaternions instead of constructing the rotation matrix and loading it manually?
2- Can I call glRotatef twice without fear of something being wrong because of Gimbal Lock?
3- Suppose the following scenario:
- I have a top down view where there is an object in the center of the screen
- I want to rotate my object over the Z axis by using the mouse's position in relation to the middle of the screen. I do this by normalizing the vector and calling atan2 to get the angle needed to rotate the object.
- Then, I also want to rotate the object so that it is parallel to the plane it is sitting on. I do this by constructing a quaternion that shifts the world up vector (0, 0, 1) to the normal of the plane.
- Finally, I came up with the following set of rotations:
1 2 3 4
glTranslatef(slime.pos.x, slime.pos.y, slime.pos.z); // From AllegroGL`s math.c glRotatef((2*acos(slime.rotation.w)) * 180 / M_PI, slime.rotation.x, slime.rotation.y, slime.rotation.z); glRotatef(mouse_angle, 0, 0, 1);
- Is this right?
- Does the order of rotations matter here?
- If not, what should I be doing instead?