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Sourcecode: acm4 version File versions  Download package

VCmpObjExt.c

#include "Vlib.h"
#include <math.h>

void
VComputeObjectExtent(obj)
VObject *obj;
{
      VPoint      sum;
      register int      i, j, npts = 0;
      register double d;

      obj->extent = 0.0;
      sum.x = 0.0;
      sum.y = 0.0;
      sum.z = 0.0;

/*
 *  Add the xyz components of each point in the object so that we can
 *  determine the average location (i.e. the center).
 */

      for (i=0; i<obj->numPolys; ++i) {

            for (j=0; j<obj->polygon[i]->numVtces; ++j) {

                  sum.x += obj->polygon[i]->vertex[j].x;
                  sum.y += obj->polygon[i]->vertex[j].y;
                  sum.z += obj->polygon[i]->vertex[j].z;
                  ++ npts;
            }
      }

      if (npts != 0) {

            obj->center.x = sum.x / npts;
            obj->center.y = sum.y / npts;
            obj->center.z = sum.z / npts;

/*
 *   Determine the most distant point from the center of the object
 */

            for (i=0; i<obj->numPolys; ++i) {
                  for (j=0; j<obj->polygon[i]->numVtces; ++j) {
                        sum.x = obj->polygon[i]->vertex[j].x -
                              obj->center.x;
                        sum.y = obj->polygon[i]->vertex[j].y -
                              obj->center.y;
                        sum.z = obj->polygon[i]->vertex[j].z -
                              obj->center.z;
                        d = sqrt (sum.x * sum.x + sum.y * sum.y +
                              sum.z * sum.z);
                        if (d > obj->extent)
                              obj->extent = d;
                  }
            }

      }
      else {
            obj->center.x = obj->center.y = obj->center.z = 0.0;
      }

}

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