Scene Rendering

A scene is rendered in the following three steps.

Determining the viewing transformation

If viewing from a scene tree Camera node is desired, a pruned traversal of the scene tree takes place to determine the viewing transformation that emulates this camera's point of view. During this traversal, all nodes are ignored except for

Group nodes,
Joint Transformation nodes,
Static Transformation nodes, and
the specified Camera node.

If viewing from the default camera is desired, the following viewpoint parameters are used:

The scene is rendered from the origin's point of view.
-z is the viewing direction.
+y points upwards.
The vertical field of view is 50 degrees.
The near and far clipping planes are at z=-1 and z=-20.

Turning on the lights

Iff the user has specified that the scene primitives be rendered as lit solids, the scene tree is traversed in order to enable and configure all OpenGL lights in the scene. If any OpenGL ID is used twice, a warning is issued, as the former usage is fully overridden by the latter. During this traversal, all nodes are ignored except for

Group nodes,
Joint Transformation nodes,
Static Transformation nodes, and
Light nodes.

Rendering the objects

The scene tree is traversed one final time in order to render all objects in the scene. During this traversal, all nodes are ignored except for

Group nodes,
Joint Transformation nodes,
Static Transformation nodes,
Material nodes, and
Light nodes.