Javadoc
Sets the color target for per-vertex colors. When lighting is
enabled and per-vertex colors are present (and not ignored) in
the geometry for a given Shape3D node, those per-vertex colors
are used in place of the specified material color(s) for this
Material object. The color target is ignored when lighting is
disabled or when per-vertex colors are not used.
The ColorInterpolator behavior also uses the color target to
determine which color in the associated Material is modified.
The default target is DIFFUSE.