
DIRECTORY G3dBasic, G3dModel, G3dPlane, G3dPolygon;

G3dNavigate: CEDAR DEFINITIONS
~ BEGIN
Spot:					TYPE ~ RECORD [point: Triple, pair: Pair, polygon: Polygon];
Intersection:			TYPE ~ RECORD [disjoint: BOOL ¬ TRUE, pt: Pair];
Seg:					TYPE ~ RECORD [p0, p1: Pair, line: Triple ¬ [0, 0, 0]];
Border:				TYPE ~ G3dBasic.Border;
NatPair:				TYPE ~ G3dBasic.NatPair;
NatSequence:			TYPE ~ G3dBasic.NatSequence;
SurfaceSequence:				TYPE ~ G3dBasic.SurfaceSequence;
Pair:					TYPE ~ G3dBasic.Pair;
PairSequence:		TYPE ~ G3dBasic.PairSequence;
PairSequenceRep:	TYPE ~ G3dBasic.PairSequenceRep;
Quad:					TYPE ~ G3dBasic.Quad;
Triple:				TYPE ~ G3dBasic.Triple;
TripleSequence:		TYPE ~ G3dBasic.TripleSequence;
TripleSequenceRep:	TYPE ~ G3dBasic.TripleSequenceRep;
Model:				TYPE ~ G3dModel.Model;
MajorPlane:			TYPE ~ G3dPlane.MajorPlane;
Polygon:				TYPE ~ G3dPolygon.Polygon;
Error: SIGNAL [reason: ATOM];
PointFromPair: PROC [pair: Pair, poly: Polygon] RETURNS [Triple];
PairOn2dLine: PROC [pair: Pair, line: Triple] RETURNS [Border];
Intersect: PROC [s0, s1: Seg] RETURNS [Intersection];
MoveSpot: PROC [old: Spot, direction: Triple, distance: REAL] RETURNS [Spot];
IntersectNextPoly: PROC [in, out: Spot] RETURNS [next: Spot];
MoveOnPolygon: PROC [old: Spot, direction: Triple, distance: REAL] RETURNS [Spot];
MoveToPolygonEdge: PROC [old: Spot, direction: Triple] RETURNS [Spot];

END.


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G3dNavigate.mesa
Copyright Ó 1988, 1992 by Xerox Corporation.  All rights reserved.
Bloomenthal, July 15, 1992 4:04 pm PDT
Local Types
Imported Types
Errors
Navigating along a Polygonal Surface
Return a 3d point with two elements from pair and the other such that
the point is on poly.plane; pair is presumed in poly.majorPlane.
poly.plane's normal is presumed unit length.

Return the status of the pair relative to the 2d line.

Return the intersection of the two segments;
if a segment's line equations is [0, 0, 0], then it is computed.

Return old moved by distance in direction.

Return spot on edge of next polygon; next.poly is the new polygon.
in is inside and out outside of the current polygon.

Move distance along spot.poly starting from spot.pt towards direction.
! Error[$EndOfModel].

Move from spot.pt towards direction until encountering edge of spot.poly.
! Error[$NilProjectionVector].
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