forked from 0ad/0ad
68 lines
2.1 KiB
C++
68 lines
2.1 KiB
C++
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/** \file sr_spline.h
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* piecewise spline */
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# ifndef SR_SPLINE_H
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# define SR_SPLINE_H
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# include <math.h>
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# include "sr_array.h"
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/*! \class SrSpline sr_spline.h
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\brief A N-dimensional piecewise cubic spline
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Implements a N-dimensional piecewise cubic spline
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Given control points x0 x1 x2 x3, "their cubic spline"
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S(t) = at3 + bt2 + ct + x0 has coefficients
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c=3(x1-x0), b=3(x2-x1)-c, a=x3-x0-c-b.
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This class is not yet implemented!
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*/
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class SrSpline
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{ private :
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int _dim; // the dimension of each point
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int _pieces; // the number of cubic pieces
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SrArray<float> _spline; // each (3*_dim) position starts one cubic spline
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private :
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public :
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/*! The constructor initializes a piecewise spline with
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given dimension and number of knots. */
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SrSpline ( int d=0, int k=0 ) { init(d,k); }
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/*! Copy constructor. */
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SrSpline ( const SrSpline& c );
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/*! Initializes spline in given dimension and number of knots.
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The start and end points are considered to be knots, thus a meaningfull
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number of knots will be >= 2. */
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void init ( int d, int k );
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/*! Returns the number of knots (which include endpoints) */
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int knots () const { return _pieces+1; }
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/*! Returns a pointer to the n-dimensional coordinates of given knot
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Parameter k must obey 0<=k<knots() */
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float* knot ( int k ) { return &_spline[k*_dim*3]; }
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/*! Returns a pointer to the n-dimensional coordinates of the control
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point c relative to the spline starting at knot k.
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Parameters must obey 0<=k<knots()-1, and 1<=c<=2 */
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float* control ( int k, int c ) { return &_spline[(k*_dim*3)+(_dim*c)]; }
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/*! Output */
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//friend SrOutput& operator<< ( SrOutput& out, const SrSpline& c );
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/*! Input */
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//friend SrInput& operator>> ( SrInput& in, SrSpline& c );
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};
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//============================== end of file ===============================
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# endif // SR_SPLINE_H
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