So I have written a Quaternion based 3D Camera oriented toward new programmers so it is ultra easy for them to integrate and begin using.
While I was developing it, at first I would take user input as Euler angles, then generate a Quaternion based off of the input for that frame. I would then take the Camera's Quaternion and multiply it by the one we generated for the input, and in theory that should simply add the input rotation to the current state of the camera's rotation, and things would be all fat and happy. Lets call this: Accumulating Quaternions, because we are storing and adding Quaternions only.
But I noticed that there was a problem with this method. The more I used it, even if I was only rotating on one Euler angle, say Yaw, it would, over some iterations, begin bleeding over into another, say Pitch. It was slight, but fairly unacceptable.
So I did some more research and found an article stating it was better to accumulate Euler angles, so the camera stores it's current rotation as Euler angles, and input is simply added to them each frame. Then I generate a Quaternion from them each frame, which is in turn used to generate my rotation matrix. And this fixed the issue of rotation bleeding into improper axes.
So do any Stackoverflow members have any insight into this problem? Is that a proper way of doing things?