
DIRECTORY  G3dBasic, G3dMatrix, G3dTube, Imager, ImplicitDefs;

ImplicitTube: CEDAR DEFINITIONS

~ BEGIN

Pair:				TYPE ~ G3dBasic.Pair;
Triple:			TYPE ~ G3dBasic.Triple;
Matrix:			TYPE ~ G3dMatrix.Matrix;
Tube:				TYPE ~ G3dTube.Tube;
Context:			TYPE ~ Imager.Context;
Sample:			TYPE ~ ImplicitDefs.Sample;
DistanceMode:	TYPE ~ ImplicitDefs.DistanceMode;
ValueProc:		TYPE ~ ImplicitDefs.ValueProc;

PrepareTube: PROC [tube: Tube, distanceMode: DistanceMode, measureMode: ATOM];
StartPoint: PROC [
tube: Tube,
valueProc: ValueProc,
threshold: REAL ¬ 1.0,
measureMode: ATOM ¬ $Unspecified,
spread: REAL ¬ 0.75,
clientData: REF ANY ¬ NIL]
RETURNS [Triple];
SampleTube: PROC [
q: Triple,
tube: Tube,
measureMode: ATOM,
distanceMode: DistanceMode,
tolerance, spread: REAL]
RETURNS [Sample];
SampleTubeBranch: PROC [
q: Triple,
tube: Tube,
measureMode: ATOM,
distanceMode: DistanceMode,
tolerance, spread: REAL]
RETURNS [Sample];

SampleTubeBranches: PROC [
q: Triple,
tube: Tube,
measureMode: ATOM,
distanceMode: DistanceMode,
tolerance, spread: REAL]
RETURNS [Sample];

SampleTubeSegment: PROC [
q: Triple,
tube: Tube,
measureMode: ATOM,
distanceMode: DistanceMode,
tolerance, spread: REAL]
RETURNS [Sample];

TextureOfTube: PROC [q: Triple, tube: Tube] RETURNS [Pair];
DiagramTube: PROC [
context: Context,
view: Matrix,
viewport: G3dMatrix.Viewport,
q: Triple,
tube: Tube,
measureMode: ATOM,
distanceMode: DistanceMode,
tolerance, spread: REAL];
END.
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ImplicitTube.mesa
Copyright c 1985 by Xerox Corporation.  All rights reserved.
Bloomenthal, August 11, 1992 4:02 pm PDT
Prepare the tube for implicit tracking.

Find a starting point for implicit tracking.

Return the sample for a tube given point q.

Return sample at q of the first tube segment of tube or its branches, whichever greatest.
Return the sample at a point q of the branches of tube.
Return the sample at a point q of the tube segment.
Return the u (circumferential) and v (longitudinal) texture coordinates.

Diagramatically explain the derivation of SampleTube[].

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