GD/GD_PrimNURBCurve.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * Produced by:
 *      Cristin Barghiel
 *      Side Effects Software Inc.
 *      20 Maud St.
 *      Toronto, Ontario,  M5V 2M5
 *      Canada
 *      416-366-4607
 *
 * NAME:        Geometry Library (C++)
 *
 * COMMENTS:
 *      This class implements a non-uniform B-Spline curve defined by 
 *      a set of knots, basis function, and CVs.
 *
 */

#ifndef __GD_PrimNURBCurve_h__
#define __GD_PrimNURBCurve_h__

#include "GD_API.h"
#include "GD_Curve.h"
#include "GD_PrimType.h"

class UT_Vector3;
class GB_NUBBasis;

class GD_API GD_PrimNURBCurve : public GD_Curve {
public:
    // Constructor that attaches this curve to detail "d".
    GD_PrimNURBCurve(GD_Detail *d) : GD_Curve(d) {}

    // Trivial class destructor, virtual by inheritance. Please read the 
    // comments on the parent class d-tor.
    virtual ~GD_PrimNURBCurve();

    // Build a new curve and insert it into the given detail.
    static GD_PrimNURBCurve     *build(GD_Detail *gdp, int npts,
                                       int order = 4, int closed = 0,
                                       int clamped = 1, int appendPts = 1);

    // Given a domain value (u), store all the basis derivatives (from 0 to du
    // inclusive) into bmatx. Return the min index of the CVs needed
    // for the linear combination. The indices may exceed the number of
    // vertices if the curve is wrapped, so remember to use % getVertexCount().
    virtual int         evaluateBasisDerivs(float u,float bmatx[][GB_MAXORDER],
                                            int &cvoffset, unsigned du = 0,
                                            int uoffset = -1) const;

    // Evaluate the basis at the given point in the domain and also return
    // the index of the first CV to linearly combine the basis with. The CV
    // index may exceed the number of vertices if the curve is wrapped,
    // so remember to use modulus (%). This method handles both rational and
    // non-rational curves.
    virtual int         evaluateBasis(float u,float *ubvals, int &cvoffset,
                                      unsigned du=0, int uoffset=-1) const;

    // Curve evaluator that takes a start and a stop index
    // in the valid knot domain and an lod representing number of points to
    // be interpolated between every two breakpoints. The methods ALWAYS
    // interpolate the encountered breakpoints (aka "edit points"). They return
    // the number of points in the list or -1 if unsuccessful. Please save
    // yourself headaches and pass VALID start and end indices (see the
    // method validInterval() in GB_Basis).
    virtual int         evaluateBreakSegm(int uStartIdx, int uStopIdx, int lod,
                                     UT_Vector3 *pos, unsigned du=0) const;

    // Given a CV index figure out the min/max indicies of the knots between
    // which the curve needs to be re-evaluated if the CV changes. If not
    // given a valid CV index, the method returns -1. Otherwise it returns 0.
    // If the curve wraps the domain we return will be rather large.
    virtual int         domainRangeOfCV(int cvidx, int &mink,int &maxk) const;

    // Convert a topologically open curve into a topologically closed one.
    // The rounded flag is mainly for surface end caps to indicate a half cap
    // or a full cap.
    virtual void        close(int rounded = 1, int preserveShape = 0);

    // Convert a topologically closed curve into a topologically open one. 
    virtual void        open(int preserveShape = 0, int = 0);

    // Check if the basis interpolates the endpoints, or change the flag.
    short               interpolatesEnds(void) const;
    void                toggleEndCondition(void);

    // Insert or delete vertices. The insertion methods return the index if
    // successful and -1 otherwise. The deletion methods return 0 if ok and
    // -1 otherwise. The insertion methods create the point if it does not
    // exist.
    virtual int         insertVertex(GD_Point  *ppt=0, unsigned int where=0);
    virtual int         appendVertex(GD_Point  *ppt=0);
    virtual int         deleteVertex(GD_Vertex &vtx);
    virtual int         deleteVertex(unsigned int num);

    // Delete the vertex that uses the point.
    virtual int         ifDetachPoint(GB_Element  *ppt) const;

    // Shift the array of vertices by an offset and wrap around. 
    // Cycle a subrange if the curve is closed and cycle the basis
    // accordingly. The offset can be either negative or positive.
    // Optionally remap the new basis to the original length and origin
    virtual int         cycle(int amount, int keepSpan = 1);

    // Reverses the vertices of the curve.
    virtual void        reverse();

    // Query the primitive type. The function is virtual by inheritance.
    virtual unsigned    getPrimitiveId(void) const;

    // Build a trim loop (which will be open unless the face is closed). The
    // loop is build every time you call this method, so it's expensive. You
    // must free the loop yourself when you are done with it. The trim pieces
    // are generated in the [ustart,ustop] or [ustop,ustart] interval, where
    // ustart and ustop are parametric values.
    virtual GD_TrimLoop *trimLoop(float ustart, float ustop) const;

protected:
    // Get a new basis of a type that matches our type:
    virtual GB_Basis    *newBasis(void) const;

private:
     // Fill the curve with data and build the basis. Return 0 if OK, and -1
     // if error.
     int                create(int nelems, int order=4, int closed = 0,
                               int interpEnds = 1, int appendPoints = 1);

};

#endif

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