Copyright (C) 1994, Digital Equipment Corp.
Created by Marc Najork
MODULE DiskGO EXPORTS DiskGO, DiskGOProxy;
IMPORT GO, GOPrivate, GraphicsBase, GraphicsBasePrivate, Matrix4, Point3,
PointProp, PointPropPrivate, Prop, RealProp, RealPropPrivate;
REVEAL
T = Public BRANDED OBJECT
prec : INTEGER;
matrix : Matrix4.T; (* transforms unit sphere into desired sphere *)
center : Point3.T; (* center achieved through matrix *)
normal : Point3.T; (* normal achieved through matrix *)
radius : REAL; (* radius achieved through matrix *)
OVERRIDES
init := Init;
draw := Draw;
damageIfDependent := DamageIfDependent;
END;
PROCEDURE Init (self : T; prec : INTEGER) : T =
BEGIN
EVAL GO.T.init (self);
self.prec := prec;
self.matrix := Matrix4.Identity ();
self.center := Point3.T {0.0, 0.0, 0.0};
self.normal := Point3.T {0.0, 0.0, 1.0};
self.radius := 1.0;
IF MkProxyT # NIL AND self.proxy = NIL THEN
MkProxyT (self);
END;
RETURN self;
END Init;
PROCEDURE DamageIfDependent (self : T; pn : Prop.Name) =
BEGIN
IF pn = Center OR pn = Normal OR pn = Radius THEN
self.damaged := TRUE;
END;
END DamageIfDependent;
PROCEDURE Draw (self : T; state : GraphicsBase.T) =
BEGIN
state.push (self);
WITH center = Center.getState (state),
normal = Normal.getState (state),
radius = Radius.getState (state) DO
IF center # self.center OR normal # self.normal OR radius # self.radius THEN
self.center := center;
self.normal := normal;
self.radius := radius;
WITH s = Point3.OrthoVector (normal),
t = Point3.CrossProduct (normal, s),
a = Point3.Plus (center, Point3.ScaleToLen (s, radius)),
b = Point3.Plus (center, Point3.ScaleToLen (t, radius)),
c = Point3.Plus (center, normal) DO
self.matrix := Matrix4.TransformUnitCube (center, a, b, c);
END;
END;
state.pushMatrix (self.matrix);
state.drawProtoDisk (self.prec);
state.popMatrix ();
state.growBoundingVolume (center, radius);
END;
self.damaged := FALSE;
state.pop (self);
END Draw;
***************************************************************************
Convenience Procedures
***************************************************************************
PROCEDURE New (p : Point3.T; n : Point3.T; r : REAL; prec := 10) : T =
VAR
disk := NEW (T).init (prec);
BEGIN
SetCenter (disk, p);
SetNormal (disk, n);
SetRadius (disk, r);
RETURN disk;
END New;
PROCEDURE SetCenter (o : GO.T; v : Point3.T) =
BEGIN
o.setProp (Center.bind (PointProp.NewConst (v)));
END SetCenter;
PROCEDURE SetNormal (o : GO.T; v : Point3.T) =
BEGIN
o.setProp (Normal.bind (PointProp.NewConst (v)));
END SetNormal;
PROCEDURE SetRadius (o : GO.T; v : REAL) =
BEGIN
o.setProp (Radius.bind (RealProp.NewConst (v)));
END SetRadius;
BEGIN
Center := NEW (PointProp.Name).init (Point3.T {0.0, 0.0, 0.0});
Normal := NEW (PointProp.Name).init (Point3.T {0.0, 0.0, 1.0});
Radius := NEW (RealProp.Name).init (1.0);
END DiskGO.