#VRML V2.0 utf8
#
#  Robot Billboard
#  robobill.wrl
#        by David R. Nadeau
#
#  This example illustrates the use of Group, Transform, and Billboard groups.
#
#  Two robots are built with their heads in Billboard groups, but their torsos
#  left out of it.  As the viewer walks about the robot, the heads always
#  turn to face the viewer.  The left robot's head is constrained to rotate
#  about the Y axis, while the right robot's head can rotate freely.
#
#  To make it clear what is, and is not moving to track the viewer, the
#  torso of the robot remains fixed, as does a background of blue slabs.
#
#  Things to experiment with:
#        Place the entire robot in the Billboard group so that the whole
#        robot tracks the viewer, not just the robot's head.
#
#        Add textures to the environment.
#
#        Add light sources, such as one placed in the lower ball of the
#        robot.  Make that ball emissive as well so that it looks like the
#        ball is the source of light.  Remember to put the light source
#        inside the robot's transform group so that as the robot moves,
#        the light source moves with it.
#
#        Add behavior to the robot.  Make it move on its own!
#

WorldInfo {
    title "Robot Billboard"
    info [ "Copyright (c) 1998, David R. Nadeau" ]
}

DEF Entry Viewpoint {
    position 0.0 3.0 12.0
    description "Entry View"
}

NavigationInfo {
    type [ "EXAMINE", "ANY" ]
    headlight TRUE
}

Background {
    skyColor [ 0.0 0.0 0.0 ]
}


#
#  Left Robot - Y-axis head rotation
#
Transform {
    translation -2.0 1.0 0.0
    scale 2.0 2.0 2.0
    children [
	#  Stationary body parts for the robot (the torso)
	DEF RoboBody Inline { url "robobody.wrl" }

	#  Parts that track the viewer using a Billboard group
	Transform {
	    translation 0.0 1.4 0.0
	    children [
		Billboard {
		    # Rotate around Y axis
		    axisOfRotation 0.0 1.0 0.0
		    children [
			DEF RoboHead Inline { url "robohead.wrl" }
		    ]
		}
	    ]
	}
    ]
}


#
#  Right Robot - unconstrained head rotation
#
Transform {
    translation 2.0 1.0 0.0
    scale 2.0 2.0 2.0
    children [
	#  Stationary body parts for the robot (the torso)
	USE RoboBody

	#  Parts that track the viewer using a Billboard group
	Transform {
	    translation 0.0 1.4 0.0
	    children [
		Billboard {
		    # Rotate around any axis
		    axisOfRotation 0.0 0.0 0.0
		    children [
			USE RoboHead
		    ]
		}
	    ]
	}
    ]
}


#
#  Environment
#
Transform {
    translation 0.0 2.0 -6.0
    children [
	DEF Slab Shape {
	    appearance Appearance {
		material Material {
		    diffuseColor 0.0 0.1 0.5
		    emissiveColor 0.0 0.3 0.5
		}
	    }
	    geometry Box {
		size 2.0 4.0 0.3
	    }
	}
    ]
}

Transform {
    translation -6.0 2.0 0.0
    children [ USE Slab ]
}

Transform {
    translation 6.0 2.0 0.0
    children [ USE Slab ]
}

Transform {
    translation -4.3 2.0 -4.3
    children [ USE Slab ]
}

Transform {
    translation 4.3 2.0 -4.3
    children [ USE Slab ]
}