A `CylinderGO.T`

is a geometric object describing a cylinder.

INTERFACECylinderGO ; IMPORT GO, Point3, PointProp, RealProp, SurfaceGO; TYPE T <: Public; Public = SurfaceGO.T OBJECT METHODS init (prec := 30) : T; END;

`cyl.init(prec)`

initializes a new cylinder`cyl`

, whose surface is composed of`prec`

rectangles, and returns it. The location and radius of the cylinder is determined by the three properties`Point1`

,`Point2`

, and`Radius`

.

VAR Point1 : PointProp.Name; Point2 : PointProp.Name; Radius : RealProp.Name;

In addition to the properties observed by all \type{GO}{T}'s and \type{SurfaceGO}{T}'s, there are three additional properties that are observed by`CylinderGO.T`

's:

`Point1`

is the name of a property that describes the first endpoint of the cylinder. It associates with a \type{PointProp}{Val}. If no`Point1`

property is specified, the cylinder starts at the origin.

`Point2`

is the name of a property that describes the second endpoint of the cylinder. It associates with a \type{PointProp}{Val}. If no`Point2`

property is specified, the cylinder ends at point (1,0,0).

`Radius`

is the name of a property that describes the radius of the cylinder. It associates with a \type{RealProp}{Val}. If no`Radius`

property is specified, the cylinder has a radius of 1.

Assume that in a given context and at a given point in time, the property mapping is such that`Point1`

maps to a point property value which evaluates to`p1`

,`Point2`

maps to a point property value which evaluates to`p2`

, and`Radius`

maps to a real property value which evaluates to`r`

.`p1`

,`p2`

, and`r`

define the position and shape of the cylinder in this context and at this time as shown below: \begin{center} \begin{tabular}{c} \psfig{figure=images/CylinderGO.ps,width=3in,silent=} \end{tabular} \end{center}

PROCEDURE New (p1, p2 : Point3.T; r : REAL; prec := 30) : T;

The following three procedures provide sugaring to attach`New(p1,p2,r,prec)`

creates a new cylinder, whose surface is composed of`prec`

rectangles, and returns it. It also attaches the following properties to the new cylinder: \begin{verbatim} (Point1,PointProp.NewConst(p1)) (Point2,PointProp.NewConst(p2)) (Radius,RealProp.NewConst(r)) \end{verbatim}

`Point1`

, `Point2`

, and `Radius`

properties with non-animated
property values to geometric objects:
PROCEDURE SetPoint1 (o : GO.T; p : Point3.T);

The expression`SetPoint1(o,p)`

is equivalent to`o.setProp(Point1.bind(PointProp.NewConst(p)))`

.

PROCEDURE SetPoint2 (o : GO.T; p : Point3.T);

The expression`SetPoint2(o,p)`

is equivalent to`o.setProp(Point2.bind(PointProp.NewConst(p))))`

.

PROCEDURE SetRadius (o : GO.T; r : REAL);

The expression`SetRadius(o,r)`

is equivalent to`o.setProp(Radius.bind(RealProp.NewConst(r))`

.

END CylinderGO.