Figure 20.10 A blinking lightbulb.
20fig10.wrl	Click on the image to view the VRML scene.

#VRML V2.0 utf8
# The VRML 2.0 Sourcebook
# Copyright (c) 1997
# Andrea L. Ames, David R. Nadeau, and John L. Moreland
Group {
    children [
    # Generic lighting for ambience
        DirectionalLight {
            intensity 0.2
            ambientIntensity 1.0
        },
    # Light bulb
        DEF BulbLight PointLight {
            radius 16.0
            color 1.0 0.0 0.0
        },
    # Light bulb shape
        Shape {
            appearance Appearance {
                material DEF BulbColor Material {
                    emissiveColor 1.0 0.3 0.3
                    diffuseColor  0.0 0.0 0.0
                }
            }
            geometry DEF Bulb Sphere { }
        },
    # Wall
        Transform {
            translation 0.0 0.0 -1.1
            rotation 1.0 0.0 0.0 1.57
            children Inline { url "mesh.wrl" }
        },
    # Animation clock
        DEF Clock TimeSensor {
            cycleInterval 4.0
            loop TRUE
        },
    # Animation brightness and colors
        DEF BulbIntensity ScalarInterpolator {
            key [ 0.0, 0.5, 0.5, 1.0 ]
            keyValue [ 1.0, 1.0, 0.0, 0.0 ]
        },
        DEF BulbDiffuse ColorInterpolator {
            key [ 0.0, 0.5, 0.5, 1.0 ]
            keyValue [
                0.0 0.0 0.0,  0.0 0.0 0.0,
                1.0 0.3 0.3,  1.0 0.3 0.3
            ]
        },
        DEF BulbEmissive ColorInterpolator {
            key [ 0.0, 0.5, 0.5, 1.0 ]
            keyValue [
                1.0 0.3 0.3,  1.0 0.3 0.3,
                0.0 0.0 0.0,  0.0 0.0 0.0,
            ]
        }
    ]
}
ROUTE Clock.fraction_changed      TO BulbIntensity.set_fraction
ROUTE Clock.fraction_changed      TO BulbDiffuse.set_fraction
ROUTE Clock.fraction_changed      TO BulbEmissive.set_fraction
ROUTE BulbIntensity.value_changed TO BulbLight.set_intensity
ROUTE BulbDiffuse.value_changed   TO BulbColor.set_diffuseColor
ROUTE BulbEmissive.value_changed  TO BulbColor.set_emissiveColor