/******************************************************************************
* CagdBSum.c - Boolean sum surface constructor out of given four curves.      *
*******************************************************************************
* Written by Gershon Elber, Sep. 91.					      *
******************************************************************************/

#ifdef __MSDOS__
#include <stdlib.h>
#include <string.h>
#include <alloc.h>
#endif /* __MSDOS__ */

#include "cagd_loc.h"

/******************************************************************************
* Constructs a boolean sum surface using the four provided boundary curves.   *
* Curve end points must meet at the corners if surface boundary should be the *
* same as the four curves.						      *
******************************************************************************/
CagdSrfStruct *CagdBoolSumSrf(CagdCrvStruct *CrvLeft,
			      CagdCrvStruct *CrvRight,
			      CagdCrvStruct *CrvTop,
			      CagdCrvStruct *CrvBottom)
{
    int i, j;
    CagdCrvStruct *Crv1, *Crv2;
    CagdSrfStruct *Ruled1, *Ruled2, *Ruled3, *Srf;
    CagdPtStruct Pt1, Pt2;
    CagdRType **SrfPoints, **Ruled1Pts, **Ruled2Pts, **Ruled3Pts;

    CrvLeft = CagdCrvCopy(CrvLeft);
    CrvRight = CagdCrvCopy(CrvRight);
    CrvTop = CagdCrvCopy(CrvTop);
    CrvBottom = CagdCrvCopy(CrvBottom);

    /* The Left-Right and Top-Bottom curves should share same point/curve     */
    /* type as well as same order and knot vector (if Bspline representation).*/
    CagdMakeCrvsCompatible(&CrvLeft, &CrvRight, TRUE, TRUE);
    CagdMakeCrvsCompatible(&CrvTop, &CrvBottom, TRUE, TRUE);

    /* The Left-Right and Top-Bottom pairs must share same point/curve type.  */
    CagdMakeCrvsCompatible(&CrvLeft, &CrvTop, FALSE, FALSE);
    CagdMakeCrvsCompatible(&CrvLeft, &CrvBottom, FALSE, FALSE);
    CagdMakeCrvsCompatible(&CrvRight, &CrvTop, FALSE, FALSE);
    CagdMakeCrvsCompatible(&CrvRight, &CrvBottom, FALSE, FALSE);

    /* Now that the curves are in the right representation, form surface(s).  */
    /* The two ruled surface between the respective curves, in right orders:  */
    Ruled1 = CagdRuledSrf(CrvLeft, CrvRight,
			  CrvTop -> Order, CrvTop -> Length);
    Ruled2 = CagdRuledSrf(CrvTop, CrvBottom,
			  CrvRight -> Order, CrvRight -> Length);
    Srf = CagdSrfReverse2(Ruled2);
    CagdSrfFree(Ruled2);
    Ruled2 = Srf;

    /* The ruled surface between the four corner points in the right orders.  */
    CagdCoerceToE3(Pt1.Pt, CrvLeft -> Points, 0, CrvLeft -> PType);
    CagdCoerceToE3(Pt2.Pt, CrvLeft -> Points, CrvLeft -> Length - 1,
							CrvLeft -> PType);
    Crv1 = CagdMergePtPt(&Pt1, &Pt2);

    CagdCoerceToE3(Pt1.Pt, CrvRight -> Points, 0, CrvRight -> PType);
    CagdCoerceToE3(Pt2.Pt, CrvRight -> Points, CrvRight -> Length - 1,
							CrvRight -> PType);
    Crv2 = CagdMergePtPt(&Pt1, &Pt2);

    /* Should not change CrvLeft/Right only Crv1/2: */
    CagdMakeCrvsCompatible(&Crv1, &CrvLeft, TRUE, TRUE);
    CagdMakeCrvsCompatible(&Crv2, &CrvRight, TRUE, TRUE);

    Ruled3 = CagdRuledSrf(Crv1, Crv2, CrvTop -> Order, CrvTop -> Length);
    CagdCrvFree(Crv1);
    CagdCrvFree(Crv2);

    /* The boolean sum is equal to Ruled1 + Ruled2 - Ruled3. This boolean     */
    /* sum as computed is not exactly as defined in the literature for non    */
    /* uniform Bsplines since the ruled surfaces are computed with uniform    */
    /* distribution along the other axis even if it is non uniform.	      */
    if (CrvRight -> GType == CAGD_CBSPLINE_TYPE) {
	Srf = BspSrfNew(Ruled1 -> ULength, Ruled1 -> VLength,
			Ruled1 -> UOrder, Ruled1 -> VOrder, Ruled1 -> PType);
	CagdFree((VoidPtr) Srf -> UKnotVector);
	Srf -> UKnotVector = BspKnotCopy(CrvLeft -> KnotVector,
					 CrvLeft -> Length + CrvLeft -> Order);
	CagdFree((VoidPtr) Srf -> VKnotVector);
	Srf -> VKnotVector = BspKnotCopy(CrvTop -> KnotVector,
					 CrvTop -> Length + CrvTop -> Order);
    }
    else if (CrvRight -> GType == CAGD_CBEZIER_TYPE)
	Srf = BzrSrfNew(Ruled1 -> ULength, Ruled1 -> VLength, Ruled1 -> PType);
    else
	FATAL_ERROR(CAGD_ERR_POWER_NO_SUPPORT);
    SrfPoints = Srf -> Points;

    Ruled1Pts = Ruled1 -> Points;
    Ruled2Pts = Ruled2 -> Points;
    Ruled3Pts = Ruled3 -> Points;

    for (i = !CAGD_IS_RATIONAL_SRF(Srf);
	 i <= CAGD_NUM_OF_PT_COORD(Srf -> PType);
	 i++) {
	CagdRType
	    *Ruled1PtsPtr = Ruled1Pts[i],
	    *Ruled2PtsPtr = Ruled2Pts[i],
	    *Ruled3PtsPtr = Ruled3Pts[i],
	    *SrfPointsPtr = SrfPoints[i];

	 for (j = Srf -> ULength * Srf -> VLength; j > 0; j--)
	     *SrfPointsPtr++ =
		 *Ruled1PtsPtr++ + *Ruled2PtsPtr++ - *Ruled3PtsPtr++;
    }

    CagdSrfFree(Ruled1);
    CagdSrfFree(Ruled2);
    CagdSrfFree(Ruled3);

    return Srf;
}