48 lines
1.7 KiB
C
48 lines
1.7 KiB
C
#include "ri.h"
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#include "patches.h"
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#define NU 13
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#define MAXNPTS 100
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#define F .5522847
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/* Listing 6.3 Version of SurfOR() taking profile points */
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/* and producing a bicubic */
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float coeff[NU][2] = {
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{ 1, 0 }, { 1, F }, { F, 1 }, { 0, 1 }, {-F, 1 }, {-1, F },
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{-1, 0 }, {-1,-F }, {-F,-1 }, { 0,-1 }, { F,-1 }, { 1,-F }, { 1, 0} };
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RtPoint mesh[MAXNPTS][NU];
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void SurfOR(Point2D points[], int npoints)
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{
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int u, v;
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/* coeff holds a matrix of coefficients for sweeping a point on the XZ
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* plane circularly around the Z axis, with the circle approximated by
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* 4 Bezier curves
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*/
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for (v = 0; v < npoints; v++) {
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/*
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* Start at the upper left of the mesh. For each
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* control point on the circle being swept out,
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* rotate every point on the XZ curve into position
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*/
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for (u = 0; u < NU; u++) {
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/* Here comes each point on the XZ curve */
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mesh[v][u][0] = points[v].x * coeff[u][0];
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mesh[v][u][1] = points[v].x * coeff[u][1];
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mesh[v][u][2] = points[v].y;
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}
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}
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// RiBasis(RiPowerBasis, RI_POWERSTEP, RiPowerBasis, RI_POWERSTEP);
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// RiBasis(RiHermiteBasis, RI_HERMITESTEP, RiHermiteBasis, RI_HERMITESTEP);
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// RiBasis(RiCatmullRomBasis, RI_CATMULLROMSTEP, RiCatmullRomBasis, RI_CATMULLROMSTEP);
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// RiBasis(RiBSplineBasis, RI_BSPLINESTEP, RiBSplineBasis, RI_BSPLINESTEP);
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RiBasis(RiBezierBasis, RI_BEZIERSTEP, RiBezierBasis, RI_BEZIERSTEP);
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RiPatchMesh(RI_BICUBIC,
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(RtInt) NU, RI_NONPERIODIC,
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(RtInt) npoints, RI_NONPERIODIC,
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RI_P, (RtPointer) mesh,
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RI_NULL);
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}
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