Posted by jmaasing on Jan 25, 2015; 6:39pm
URL: https://forum.jogamp.org/Camera-class-for-parallel-projection-tp4033907p4033924.html

Another common way to handle the camera is by defining it through 3 vectors (up, forward, right for example). There is no gimbal lock since there are no angles stored but leaves some more calculations to the user of the camera to turn it around et c

There are o.f.c. many camer aimplementations in the scene graph APIs, I'm sure guossej can point to Ardor3D.
Here is libgdx camera.
https://github.com/libgdx/libgdx/blob/master/gdx/src/com/badlogic/gdx/graphics/OrthographicCamera.java

And jMonkeyEngine:
https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-core/src/main/java/com/jme3/renderer/Camera.java

Hope that gives some inspiration.