A JavaScript 3D Rotation Calculator
Written by Johnny Ernest
Camera Panning
Euler Rotation Addition/Subtraction [Original += Increment]
Pre-Multiply Quaternion/Matrix [Increment *= Original]
Post-Multiply Quaternion/Matrix [Original *= Increment]
Note in the above that Euler X+/- is the same as Quaternion Pre-Multiply X+/-, and that Euler Z+/- is the same as Quaternion Post-Multiply Z+/-, but Euler Pitch Angle Y+/- is slightly different than Pre/Post-Multiply.
Note also that additional math formulas are used to retain the Euler angle in a human readable format when the pitch angle changes between 90 degrees and 270 degrees.
Euler Pitch Angle Addition/Subtraction Emulation by Quaternion Multiplication
Euler to Quaternion Formulas
Note that the order of multiplication matters in the below.
Quaternion Solver