/* Copyrighted Pixar 1989 */
/* From the RenderMan Companion p. 81 */
/* Listing 5.3  Bowling pin with normals assigned to vertices, defined using RiPointsPolygons  */

#include "ri.h"
#include "patches.h"

#define MAXNPTS 100
#define BEZIERWIDTH    12
#define F .5522847

/* Copyrighted Pixar 1989 */
/* From the RenderMan Companion p. 102 */ 
/* Listing 6.4  Defining a surface of revolution using a wrapped patch mesh */

RtPoint mesh[MAXNPTS][BEZIERWIDTH];

float coeff[BEZIERWIDTH][2] = { 
    { 1, 0 }, { 1, F }, { F, 1 }, { 0, 1 }, {-F, 1 }, {-1, F }, 
    {-1, 0 }, {-1,-F }, {-F,-1 }, { 0,-1 }, { F,-1 }, { 1,-F }  };

void BezierSurfOR(Point2D points[], int npoints, RtPoint mesh[][BEZIERWIDTH])
{
    int u, v;
    /*
     *  coeff holds a matrix of coefficients for sweeping a point on the XZ
     *  plane circularly around the Z axis, with the circle approximated by 
     *  4 Bezier curves.
     */
    for (v = 0; v < npoints; v++) {    
        /* 
         *  Start at the upper left of the mesh. 
         *  For each control point on the circle being swept out, 
         *  rotate every point on the XZ curve into position.
         */
        for (u = 0; u < BEZIERWIDTH; u++) {    
            /*  Here comes each point on the XZ curve */
            mesh[v][u][0] = points[v].x * coeff[u][0];
            mesh[v][u][1] = points[v].x * coeff[u][1];
            mesh[v][u][2] = points[v].y;
        }
    }
}

void SurfOR(Point2D points[], int npoints)
{
    BezierSurfOR(points, npoints, mesh);
    RiBasis(RiBezierBasis, RI_BEZIERSTEP,
            RiBezierBasis, RI_BEZIERSTEP);
    RiPatchMesh(RI_BICUBIC,
           (RtInt) BEZIERWIDTH, RI_PERIODIC,
           (RtInt) npoints, RI_NONPERIODIC,
           RI_P, (RtPointer) mesh, RI_NULL);
}