The first camera defined is the default view point when the browser first loads the world. Subsequent camera definitions can be selected by the user from the browser. Name is a string containing no spaces and will appear as a name in the browser for selecting this camera. Xpos, Ypos, Zpos are the coordinates of the camera's position. XFrac, YFrac, ZFrac compose a vector over which the camera is rotated by Angle radians.
Directional lights allow users to specify lights which are positioned infinitely far away.
All light rays coming from the light source are parallel and point in the same direction. In the real world, the sun is a directional light. Intensity is a numeric which ranges from -1 to 1. Negative values suck light from the scene. The more negative the value, the more light is sucked from the world.