#include "Vlib.h"

VPolygon *
VGetPlanes(VPolygon * poly)
{

	VPoint    tmp[64], *p;
	int       i, lasti;

	lasti = poly->numVtces - 1;
	p = poly->vertex;

	for (i = 0; i < poly->numVtces; ++i) {
		tmp[i].x = p->y * poly->vertex[lasti].z - p->z *
			poly->vertex[lasti].y;
		tmp[i].y = p->z * poly->vertex[lasti].x - p->x *
			poly->vertex[lasti].z;
		tmp[i].z = p->x * poly->vertex[lasti].y - p->y *
			poly->vertex[lasti].x;
		lasti = i;
		p++;
	}

	for (i = 0; i < poly->numVtces; ++i)
		poly->vertex[i] = tmp[i];

	return poly;
}
