/******************************************************************************
* Constrct.c - construction of surfaces using algebraic tools.		      *
*******************************************************************************
* (C) Gershon Elber, Technion, Israel Institute of Technology                 *
*******************************************************************************
* Written by Gershon Elber, May 98					      *
******************************************************************************/

#include "symb_loc.h"

/*****************************************************************************
* DESCRIPTION:                                                               M
*   Adds up algebraically the given two curves, C1(r) and C2(t).  The result M
* is a bivariate surface S(r, t) = C1(r) + C2(t).                            M
*                                                                            *
* PARAMETERS:                                                                M
*   Crv1, Crv2:    Two curves to sum algebraically.                          M
*                                                                            *
* RETURN VALUE:                                                              M
*   CagdSrfStruct *:    A surface represent their sum, algebraically.        M
*                                                                            *
* SEE ALSO:                                                                  M
*   SymbSwungAlgSumSrf, SymbAlgebraicProdSrf	                             M
*                                                                            *
* KEYWORDS:                                                                  M
*   SymbAlgebraicSumSrf                                                      M
*****************************************************************************/
CagdSrfStruct *SymbAlgebraicSumSrf(CagdCrvStruct *Crv1, CagdCrvStruct *Crv2)
{
    CagdSrfStruct *Srf,
	*Srf1 = CagdPromoteCrvToSrf(Crv1, CAGD_CONST_U_DIR),
	*Srf2 = CagdPromoteCrvToSrf(Crv2, CAGD_CONST_V_DIR);

    if (!CagdMakeSrfsCompatible(&Srf1, &Srf2, TRUE, TRUE, TRUE, TRUE) ||
	(Srf = SymbSrfAdd(Srf1, Srf2)) == NULL) {
	SYMB_FATAL_ERROR(SYMB_ERR_SRFS_INCOMPATIBLE);
	return NULL;
    }

    CagdSrfFree(Srf1);
    CagdSrfFree(Srf2);

    return Srf;
}

/*****************************************************************************
* DESCRIPTION:                                                               M
*   Multiply up algebraically the given two curves, C1(r) and C2(t).  The    M
* result is a bivariate surface S(r, t) = C1(r) C2(t).                       M
*                                                                            *
* PARAMETERS:                                                                M
*   Crv1, Crv2:    Two curves to multiply algebraically.                     M
*                                                                            *
* RETURN VALUE:                                                              M
*   CagdSrfStruct *:    A surface represent their product, algebraically.    M
*                                                                            *
* SEE ALSO:                                                                  M
*   SymbAlgebraicSumSrf, SymbSwungAlgSumSrf	                             M
*                                                                            *
* KEYWORDS:                                                                  M
*   SymbAlgebraicProdSrf                                                     M
*****************************************************************************/
CagdSrfStruct *SymbAlgebraicProdSrf(CagdCrvStruct *Crv1, CagdCrvStruct *Crv2)
{
    CagdSrfStruct *Srf,
	*Srf1 = CagdPromoteCrvToSrf(Crv1, CAGD_CONST_U_DIR),
	*Srf2 = CagdPromoteCrvToSrf(Crv2, CAGD_CONST_V_DIR);

    if (!CagdMakeSrfsCompatible(&Srf1, &Srf2, TRUE, TRUE, TRUE, TRUE) ||
	(Srf = SymbSrfMult(Srf1, Srf2)) == NULL) {
	SYMB_FATAL_ERROR(SYMB_ERR_SRFS_INCOMPATIBLE);
	return NULL;
    }

    CagdSrfFree(Srf1);
    CagdSrfFree(Srf2);

    return Srf;
}

/*****************************************************************************
* DESCRIPTION:                                                               M
*   Adds up algebraically the given two curves, C1(r) and C2(t), as swung    M
* surfaces (The NURBs book', by Piegl and Tiller, pp 455):		     M
*                                                                            M
*     S(r, t) = (x1(r) x2(t), x1(r) y2(t), y1(r))                            M
*                                                                            *
* PARAMETERS:                                                                M
*   Crv1, Crv2:    Two curves to sum algebraically, forming a swung surface. M
*                                                                            *
* RETURN VALUE:                                                              M
*   CagdSrfStruct *:    A surface represent their swung algebraic sum.       M
*                                                                            *
* SEE ALSO:                                                                  M
*   SymbAlgebraicProdSrf, SymbAlgebraicSumSrf		                     M
*                                                                            *
* KEYWORDS:                                                                  M
*   SymbSwungAlgSumSrf                                                       M
*****************************************************************************/
CagdSrfStruct *SymbSwungAlgSumSrf(CagdCrvStruct *Crv1, CagdCrvStruct *Crv2)
{
    CagdSrfStruct *Srf, *SrfW, *SrfX, *SrfY, *SrfZ, *Srf1, *Srf2,
        *Srf1W, *Srf1X, *Srf1Y, *Srf1Z, *Srf2W, *Srf2X, *Srf2Y, *Srf2Z;

    if (CAGD_NUM_OF_PT_COORD(Crv1 -> PType) < 2 ||
	CAGD_NUM_OF_PT_COORD(Crv1 -> PType) > 3 ||
	CAGD_NUM_OF_PT_COORD(Crv2 -> PType) < 2 ||
	CAGD_NUM_OF_PT_COORD(Crv2 -> PType) > 3) {
	SYMB_FATAL_ERROR(SYMB_ERR_ONLY_2D_OR_3D);
	return NULL;
    }

    Srf1 = CagdPromoteCrvToSrf(Crv1, CAGD_CONST_U_DIR),
    Srf2 = CagdPromoteCrvToSrf(Crv2, CAGD_CONST_V_DIR);
    if (!CagdMakeSrfsCompatible(&Srf1, &Srf2, TRUE, TRUE, TRUE, TRUE)) {
	SYMB_FATAL_ERROR(SYMB_ERR_SRFS_INCOMPATIBLE);
	CagdSrfFree(Srf1);
	CagdSrfFree(Srf2);
	return NULL;
    }

    SymbSrfSplitScalar(Srf1, &Srf1W, &Srf1X, &Srf1Y, &Srf1Z);
    SymbSrfSplitScalar(Srf2, &Srf2W, &Srf2X, &Srf2Y, &Srf2Z);
    CagdSrfFree(Srf1);
    CagdSrfFree(Srf2);

    SrfX = SymbSrfMult(Srf1X, Srf2X);
    SrfY = SymbSrfMult(Srf1X, Srf2Y);
    SrfZ = Srf2W == NULL ? CagdSrfCopy(Srf1Y) : SymbSrfMult(Srf1Y, Srf2W);
    SrfW = Srf2W == NULL ? Srf1W
	                 : (Srf1W == NULL ? Srf2W : SymbSrfMult(Srf1W, Srf2W));
    CagdSrfFree(Srf1X);
    CagdSrfFree(Srf2X);
    CagdSrfFree(Srf1Y);
    CagdSrfFree(Srf2Y);
    if (Srf1Z != NULL)
	CagdSrfFree(Srf1Z);
    if (Srf2Z != NULL)
	CagdSrfFree(Srf2Z);
    if (Srf1W != NULL)
	CagdSrfFree(Srf1W);
    if (Srf2W != NULL)
	CagdSrfFree(Srf2W);

    if (!CagdMakeSrfsCompatible(&SrfX, &SrfY, TRUE, TRUE, TRUE, TRUE) ||
	!CagdMakeSrfsCompatible(&SrfX, &SrfZ, TRUE, TRUE, TRUE, TRUE) ||
	!CagdMakeSrfsCompatible(&SrfY, &SrfZ, TRUE, TRUE, TRUE, TRUE) ||
	(SrfW != NULL &&
	 (!CagdMakeSrfsCompatible(&SrfW, &SrfX, TRUE, TRUE, TRUE, TRUE) ||
	  !CagdMakeSrfsCompatible(&SrfW, &SrfY, TRUE, TRUE, TRUE, TRUE) ||
	  !CagdMakeSrfsCompatible(&SrfW, &SrfZ, TRUE, TRUE, TRUE, TRUE)))) {
	SYMB_FATAL_ERROR(SYMB_ERR_SRFS_INCOMPATIBLE);
	return NULL;
    }

    Srf = SymbSrfMergeScalar(SrfW, SrfX, SrfY, SrfZ);

    CagdSrfFree(SrfX);
    CagdSrfFree(SrfY);
    CagdSrfFree(SrfZ);
    if (SrfW != NULL)
	CagdSrfFree(SrfW);

    return Srf;
}