+/**
+Represents a point of view in 3D space.
+
+A Camera provides two matrices. The view matrix is the inverse of the camera's
+model matrix and transforms coordinates from world space to eye space (the
+camera's object space). The projection matrix transforms coordinates from eye
+space to clip space.
+
+Orientation of the Camera is determined by look direction and up direction.
+Look direction corresponds to the negative Z axis direction in eye space. The
+YZ plane of eye space is aligned to the plane formed by the look and up
+directions. Setting the up direction to the opposite of gravity direction is
+an easy way to keep the camera upright.
+*/