Improving camera orientations
Regardless of the direction the camera is facing, when flying around in a 3D environment, being able to yaw around the world’s up axis is far less disorientating than yawing at an unexpected angle, no matter how mathematically correct it may be. Rolling around the forward-facing vector of the camera is however intuitive as it is the way the viewer is facing. Many first-person player controllers are set up to rotate around the world's up axis and the camera-forward axis as shown in Figure 15.5. It prevents the camera tipping accidentally upside down and experiencing gimbal lock.
Figure 15.5: Intuitive camera flying rotation axes
To instigate rotations using these axes, we need to be able to switch between local and world space. In this instance we want to rotate the camera in world space (where it yaws around the up axis) and roll around the local z axis, which is the axis that indicates the direction the camera is...
