/**
 * @file m4math.cpp
 * @brief LLMatrix4 class implementation.
 *
 * $LicenseInfo:firstyear=2000&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"

//#include "vmath.h"
#include "v3math.h"
#include "v4math.h"
#include "m4math.h"
#include "m3math.h"
#include "llquaternion.h"
#include "llmatrix4a.h"


// LLMatrix4

// Constructors


LLMatrix4::LLMatrix4(const F32 *mat)
{
    mMatrix[0][0] = mat[0];
    mMatrix[0][1] = mat[1];
    mMatrix[0][2] = mat[2];
    mMatrix[0][3] = mat[3];

    mMatrix[1][0] = mat[4];
    mMatrix[1][1] = mat[5];
    mMatrix[1][2] = mat[6];
    mMatrix[1][3] = mat[7];

    mMatrix[2][0] = mat[8];
    mMatrix[2][1] = mat[9];
    mMatrix[2][2] = mat[10];
    mMatrix[2][3] = mat[11];

    mMatrix[3][0] = mat[12];
    mMatrix[3][1] = mat[13];
    mMatrix[3][2] = mat[14];
    mMatrix[3][3] = mat[15];
}

LLMatrix4::LLMatrix4(const LLMatrix3 &mat, const LLVector4 &vec)
{
    mMatrix[0][0] = mat.mMatrix[0][0];
    mMatrix[0][1] = mat.mMatrix[0][1];
    mMatrix[0][2] = mat.mMatrix[0][2];
    mMatrix[0][3] = 0.f;

    mMatrix[1][0] = mat.mMatrix[1][0];
    mMatrix[1][1] = mat.mMatrix[1][1];
    mMatrix[1][2] = mat.mMatrix[1][2];
    mMatrix[1][3] = 0.f;

    mMatrix[2][0] = mat.mMatrix[2][0];
    mMatrix[2][1] = mat.mMatrix[2][1];
    mMatrix[2][2] = mat.mMatrix[2][2];
    mMatrix[2][3] = 0.f;

    mMatrix[3][0] = vec.mV[0];
    mMatrix[3][1] = vec.mV[1];
    mMatrix[3][2] = vec.mV[2];
    mMatrix[3][3] = 1.f;
}

LLMatrix4::LLMatrix4(const LLMatrix3 &mat)
{
    mMatrix[0][0] = mat.mMatrix[0][0];
    mMatrix[0][1] = mat.mMatrix[0][1];
    mMatrix[0][2] = mat.mMatrix[0][2];
    mMatrix[0][3] = 0.f;

    mMatrix[1][0] = mat.mMatrix[1][0];
    mMatrix[1][1] = mat.mMatrix[1][1];
    mMatrix[1][2] = mat.mMatrix[1][2];
    mMatrix[1][3] = 0.f;

    mMatrix[2][0] = mat.mMatrix[2][0];
    mMatrix[2][1] = mat.mMatrix[2][1];
    mMatrix[2][2] = mat.mMatrix[2][2];
    mMatrix[2][3] = 0.f;

    mMatrix[3][0] = 0.f;
    mMatrix[3][1] = 0.f;
    mMatrix[3][2] = 0.f;
    mMatrix[3][3] = 1.f;
}

LLMatrix4::LLMatrix4(const LLQuaternion &q)
{
    *this = initRotation(q);
}

LLMatrix4::LLMatrix4(const LLMatrix4a& mat)
    : LLMatrix4(mat.getF32ptr())
{

}

LLMatrix4::LLMatrix4(const LLQuaternion &q, const LLVector4 &pos)
{
    *this = initRotTrans(q, pos);
}

LLMatrix4::LLMatrix4(const F32 angle, const LLVector4 &vec, const LLVector4 &pos)
{
    initRotTrans(LLQuaternion(angle, vec), pos);
}

LLMatrix4::LLMatrix4(const F32 angle, const LLVector4 &vec)
{
    initRotation(LLQuaternion(angle, vec));

    mMatrix[3][0] = 0.f;
    mMatrix[3][1] = 0.f;
    mMatrix[3][2] = 0.f;
    mMatrix[3][3] = 1.f;
}

LLMatrix4::LLMatrix4(const F32 roll, const F32 pitch, const F32 yaw, const LLVector4 &pos)
{
    LLMatrix3   mat(roll, pitch, yaw);
    initRotTrans(LLQuaternion(mat), pos);
}

LLMatrix4::LLMatrix4(const F32 roll, const F32 pitch, const F32 yaw)
{
    LLMatrix3   mat(roll, pitch, yaw);
    initRotation(LLQuaternion(mat));

    mMatrix[3][0] = 0.f;
    mMatrix[3][1] = 0.f;
    mMatrix[3][2] = 0.f;
    mMatrix[3][3] = 1.f;
}

LLMatrix4::~LLMatrix4(void)
{
}

// Clear and Assignment Functions

const LLMatrix4& LLMatrix4::setZero()
{
    mMatrix[0][0] = 0.f;
    mMatrix[0][1] = 0.f;
    mMatrix[0][2] = 0.f;
    mMatrix[0][3] = 0.f;

    mMatrix[1][0] = 0.f;
    mMatrix[1][1] = 0.f;
    mMatrix[1][2] = 0.f;
    mMatrix[1][3] = 0.f;

    mMatrix[2][0] = 0.f;
    mMatrix[2][1] = 0.f;
    mMatrix[2][2] = 0.f;
    mMatrix[2][3] = 0.f;

    mMatrix[3][0] = 0.f;
    mMatrix[3][1] = 0.f;
    mMatrix[3][2] = 0.f;
    mMatrix[3][3] = 0.f;
    return *this;
}


// various useful mMatrix functions

const LLMatrix4&    LLMatrix4::transpose()
{
    LLMatrix4 mat;
    mat.mMatrix[0][0] = mMatrix[0][0];
    mat.mMatrix[1][0] = mMatrix[0][1];
    mat.mMatrix[2][0] = mMatrix[0][2];
    mat.mMatrix[3][0] = mMatrix[0][3];

    mat.mMatrix[0][1] = mMatrix[1][0];
    mat.mMatrix[1][1] = mMatrix[1][1];
    mat.mMatrix[2][1] = mMatrix[1][2];
    mat.mMatrix[3][1] = mMatrix[1][3];

    mat.mMatrix[0][2] = mMatrix[2][0];
    mat.mMatrix[1][2] = mMatrix[2][1];
    mat.mMatrix[2][2] = mMatrix[2][2];
    mat.mMatrix[3][2] = mMatrix[2][3];

    mat.mMatrix[0][3] = mMatrix[3][0];
    mat.mMatrix[1][3] = mMatrix[3][1];
    mat.mMatrix[2][3] = mMatrix[3][2];
    mat.mMatrix[3][3] = mMatrix[3][3];

    *this = mat;
    return *this;
}


F32 LLMatrix4::determinant() const
{
    F32 value =
        mMatrix[0][3] * mMatrix[1][2] * mMatrix[2][1] * mMatrix[3][0] -
        mMatrix[0][2] * mMatrix[1][3] * mMatrix[2][1] * mMatrix[3][0] -
        mMatrix[0][3] * mMatrix[1][1] * mMatrix[2][2] * mMatrix[3][0] +
        mMatrix[0][1] * mMatrix[1][3] * mMatrix[2][2] * mMatrix[3][0] +
        mMatrix[0][2] * mMatrix[1][1] * mMatrix[2][3] * mMatrix[3][0] -
        mMatrix[0][1] * mMatrix[1][2] * mMatrix[2][3] * mMatrix[3][0] -
        mMatrix[0][3] * mMatrix[1][2] * mMatrix[2][0] * mMatrix[3][1] +
        mMatrix[0][2] * mMatrix[1][3] * mMatrix[2][0] * mMatrix[3][1] +
        mMatrix[0][3] * mMatrix[1][0] * mMatrix[2][2] * mMatrix[3][1] -
        mMatrix[0][0] * mMatrix[1][3] * mMatrix[2][2] * mMatrix[3][1] -
        mMatrix[0][2] * mMatrix[1][0] * mMatrix[2][3] * mMatrix[3][1] +
        mMatrix[0][0] * mMatrix[1][2] * mMatrix[2][3] * mMatrix[3][1] +
        mMatrix[0][3] * mMatrix[1][1] * mMatrix[2][0] * mMatrix[3][2] -
        mMatrix[0][1] * mMatrix[1][3] * mMatrix[2][0] * mMatrix[3][2] -
        mMatrix[0][3] * mMatrix[1][0] * mMatrix[2][1] * mMatrix[3][2] +
        mMatrix[0][0] * mMatrix[1][3] * mMatrix[2][1] * mMatrix[3][2] +
        mMatrix[0][1] * mMatrix[1][0] * mMatrix[2][3] * mMatrix[3][2] -
        mMatrix[0][0] * mMatrix[1][1] * mMatrix[2][3] * mMatrix[3][2] -
        mMatrix[0][2] * mMatrix[1][1] * mMatrix[2][0] * mMatrix[3][3] +
        mMatrix[0][1] * mMatrix[1][2] * mMatrix[2][0] * mMatrix[3][3] +
        mMatrix[0][2] * mMatrix[1][0] * mMatrix[2][1] * mMatrix[3][3] -
        mMatrix[0][0] * mMatrix[1][2] * mMatrix[2][1] * mMatrix[3][3] -
        mMatrix[0][1] * mMatrix[1][0] * mMatrix[2][2] * mMatrix[3][3] +
        mMatrix[0][0] * mMatrix[1][1] * mMatrix[2][2] * mMatrix[3][3];

    return value;
}

// Only works for pure orthonormal, homogeneous transform matrices.
const LLMatrix4&    LLMatrix4::invert(void)
{
    // transpose the rotation part
    F32 temp;
    temp = mMatrix[VX][VY]; mMatrix[VX][VY] = mMatrix[VY][VX]; mMatrix[VY][VX] = temp;
    temp = mMatrix[VX][VZ]; mMatrix[VX][VZ] = mMatrix[VZ][VX]; mMatrix[VZ][VX] = temp;
    temp = mMatrix[VY][VZ]; mMatrix[VY][VZ] = mMatrix[VZ][VY]; mMatrix[VZ][VY] = temp;

    // rotate the translation part by the new rotation
    // (temporarily store in empty column of matrix)
    U32 j;
    for (j=0; j<3; j++)
    {
        mMatrix[j][VW] =  mMatrix[VW][VX] * mMatrix[VX][j] +
                          mMatrix[VW][VY] * mMatrix[VY][j] +
                          mMatrix[VW][VZ] * mMatrix[VZ][j];
    }

    // negate and copy the temporary vector back to the tranlation row
    mMatrix[VW][VX] = -mMatrix[VX][VW];
    mMatrix[VW][VY] = -mMatrix[VY][VW];
    mMatrix[VW][VZ] = -mMatrix[VZ][VW];

    // zero the empty column again
    mMatrix[VX][VW] = mMatrix[VY][VW] = mMatrix[VZ][VW] = 0.0f;

    return *this;
}

// Convenience func for simplifying comparison-heavy code by
// intentionally stomping values in [-FLT_EPS,FLT_EPS] to 0.0f
//
void LLMatrix4::condition(void)
{
    U32 i;
    U32 j;
    for (i = 0; i < 3;i++)
        for (j = 0; j < 3;j++)
            mMatrix[i][j] = ((mMatrix[i][j] > -FLT_EPSILON)
                              && (mMatrix[i][j] < FLT_EPSILON)) ? 0.0f : mMatrix[i][j];
}

LLVector4 LLMatrix4::getFwdRow4() const
{
    return LLVector4(mMatrix[VX][VX], mMatrix[VX][VY], mMatrix[VX][VZ], mMatrix[VX][VW]);
}

LLVector4 LLMatrix4::getLeftRow4() const
{
    return LLVector4(mMatrix[VY][VX], mMatrix[VY][VY], mMatrix[VY][VZ], mMatrix[VY][VW]);
}

LLVector4 LLMatrix4::getUpRow4() const
{
    return LLVector4(mMatrix[VZ][VX], mMatrix[VZ][VY], mMatrix[VZ][VZ], mMatrix[VZ][VW]);
}

// SJB: This code is correct for a logicly stored (non-transposed) matrix;
//      Our matrices are stored transposed, OpenGL style, so this generates the
//      INVERSE quaternion (-x, -y, -z, w)!
//      Because we use similar logic in LLQuaternion::getMatrix3,
//      we are internally consistant so everything works OK :)
LLQuaternion    LLMatrix4::quaternion() const
{
    LLQuaternion    quat;
    F32     tr, s, q[4];
    U32     i, j, k;
    U32     nxt[3] = {1, 2, 0};

    tr = mMatrix[0][0] + mMatrix[1][1] + mMatrix[2][2];

    // check the diagonal
    if (tr > 0.f)
    {
        s = (F32)sqrt (tr + 1.f);
        quat.mQ[VS] = s / 2.f;
        s = 0.5f / s;
        quat.mQ[VX] = (mMatrix[1][2] - mMatrix[2][1]) * s;
        quat.mQ[VY] = (mMatrix[2][0] - mMatrix[0][2]) * s;
        quat.mQ[VZ] = (mMatrix[0][1] - mMatrix[1][0]) * s;
    }
    else
    {
        // diagonal is negative
        i = 0;
        if (mMatrix[1][1] > mMatrix[0][0])
            i = 1;
        if (mMatrix[2][2] > mMatrix[i][i])
            i = 2;

        j = nxt[i];
        k = nxt[j];


        s = (F32)sqrt ((mMatrix[i][i] - (mMatrix[j][j] + mMatrix[k][k])) + 1.f);

        q[i] = s * 0.5f;

        if (s != 0.f)
            s = 0.5f / s;

        q[3] = (mMatrix[j][k] - mMatrix[k][j]) * s;
        q[j] = (mMatrix[i][j] + mMatrix[j][i]) * s;
        q[k] = (mMatrix[i][k] + mMatrix[k][i]) * s;

        quat.setQuat(q);
    }
    return quat;
}



void LLMatrix4::initRows(const LLVector4 &row0,
                         const LLVector4 &row1,
                         const LLVector4 &row2,
                         const LLVector4 &row3)
{
    mMatrix[0][0] = row0.mV[0];
    mMatrix[0][1] = row0.mV[1];
    mMatrix[0][2] = row0.mV[2];
    mMatrix[0][3] = row0.mV[3];

    mMatrix[1][0] = row1.mV[0];
    mMatrix[1][1] = row1.mV[1];
    mMatrix[1][2] = row1.mV[2];
    mMatrix[1][3] = row1.mV[3];

    mMatrix[2][0] = row2.mV[0];
    mMatrix[2][1] = row2.mV[1];
    mMatrix[2][2] = row2.mV[2];
    mMatrix[2][3] = row2.mV[3];

    mMatrix[3][0] = row3.mV[0];
    mMatrix[3][1] = row3.mV[1];
    mMatrix[3][2] = row3.mV[2];
    mMatrix[3][3] = row3.mV[3];
}


const LLMatrix4&    LLMatrix4::initRotation(F32 angle, const LLVector4 &vec)
{
    LLMatrix3   mat(angle, vec);
    return initMatrix(mat);
}


const LLMatrix4&    LLMatrix4::initRotation(const F32 roll, const F32 pitch, const F32 yaw)
{
    LLMatrix3   mat(roll, pitch, yaw);
    return initMatrix(mat);
}


const LLMatrix4&    LLMatrix4::initRotation(const LLQuaternion &q)
{
    LLMatrix3   mat(q);
    return initMatrix(mat);
}


const LLMatrix4&    LLMatrix4::initRotTrans(const F32 angle, const LLVector3 &axis, const LLVector3&translation)
{
    LLMatrix3   mat(angle, axis);
    initMatrix(mat);
    setTranslation(translation);
    return (*this);
}

const LLMatrix4&    LLMatrix4::initRotTrans(const F32 roll, const F32 pitch, const F32 yaw, const LLVector4 &translation)
{
    LLMatrix3   mat(roll, pitch, yaw);
    initMatrix(mat);
    setTranslation(translation);
    return (*this);
}

/*
const LLMatrix4&    LLMatrix4::initRotTrans(const LLVector4 &fwd,
                                            const LLVector4 &left,
                                            const LLVector4 &up,
                                            const LLVector4 &translation)
{
    LLMatrix3 mat(fwd, left, up);
    initMatrix(mat);
    setTranslation(translation);
    return (*this);
}
*/

const LLMatrix4&    LLMatrix4::initRotTrans(const LLQuaternion &q, const LLVector4 &translation)
{
    LLMatrix3   mat(q);
    initMatrix(mat);
    setTranslation(translation);
    return (*this);
}

const LLMatrix4& LLMatrix4::initScale(const LLVector3 &scale)
{
    setIdentity();

    mMatrix[VX][VX] = scale.mV[VX];
    mMatrix[VY][VY] = scale.mV[VY];
    mMatrix[VZ][VZ] = scale.mV[VZ];

    return (*this);
}

const LLMatrix4& LLMatrix4::initAll(const LLVector3 &scale, const LLQuaternion &q, const LLVector3 &pos)
{
    F32     sx, sy, sz;
    F32     xx, xy, xz, xw, yy, yz, yw, zz, zw;

    sx      = scale.mV[0];
    sy      = scale.mV[1];
    sz      = scale.mV[2];

    xx      = q.mQ[VX] * q.mQ[VX];
    xy      = q.mQ[VX] * q.mQ[VY];
    xz      = q.mQ[VX] * q.mQ[VZ];
    xw      = q.mQ[VX] * q.mQ[VW];

    yy      = q.mQ[VY] * q.mQ[VY];
    yz      = q.mQ[VY] * q.mQ[VZ];
    yw      = q.mQ[VY] * q.mQ[VW];

    zz      = q.mQ[VZ] * q.mQ[VZ];
    zw      = q.mQ[VZ] * q.mQ[VW];

    mMatrix[0][0]  = (1.f - 2.f * ( yy + zz )) *sx;
    mMatrix[0][1]  = (      2.f * ( xy + zw )) *sx;
    mMatrix[0][2]  = (      2.f * ( xz - yw )) *sx;

    mMatrix[1][0]  = (      2.f * ( xy - zw )) *sy;
    mMatrix[1][1]  = (1.f - 2.f * ( xx + zz )) *sy;
    mMatrix[1][2]  = (      2.f * ( yz + xw )) *sy;

    mMatrix[2][0]  = (      2.f * ( xz + yw )) *sz;
    mMatrix[2][1]  = (      2.f * ( yz - xw )) *sz;
    mMatrix[2][2]  = (1.f - 2.f * ( xx + yy )) *sz;

    mMatrix[3][0]  = pos.mV[0];
    mMatrix[3][1]  = pos.mV[1];
    mMatrix[3][2]  = pos.mV[2];
    mMatrix[3][3]  = 1.0;

    // TODO -- should we set the translation portion to zero?
    return (*this);
}

const LLMatrix4&    LLMatrix4::rotate(const F32 angle, const LLVector4 &vec)
{
    LLMatrix4   mat(angle, vec);
    *this *= mat;
    return *this;
}

const LLMatrix4&    LLMatrix4::rotate(const F32 roll, const F32 pitch, const F32 yaw)
{
    LLMatrix4   mat(roll, pitch, yaw);
    *this *= mat;
    return *this;
}

const LLMatrix4&    LLMatrix4::rotate(const LLQuaternion &q)
{
    LLMatrix4   mat(q);
    *this *= mat;
    return *this;
}


const LLMatrix4&    LLMatrix4::translate(const LLVector3 &vec)
{
    mMatrix[3][0] += vec.mV[0];
    mMatrix[3][1] += vec.mV[1];
    mMatrix[3][2] += vec.mV[2];
    return (*this);
}


void LLMatrix4::setFwdRow(const LLVector3 &row)
{
    mMatrix[VX][VX] = row.mV[VX];
    mMatrix[VX][VY] = row.mV[VY];
    mMatrix[VX][VZ] = row.mV[VZ];
}

void LLMatrix4::setLeftRow(const LLVector3 &row)
{
    mMatrix[VY][VX] = row.mV[VX];
    mMatrix[VY][VY] = row.mV[VY];
    mMatrix[VY][VZ] = row.mV[VZ];
}

void LLMatrix4::setUpRow(const LLVector3 &row)
{
    mMatrix[VZ][VX] = row.mV[VX];
    mMatrix[VZ][VY] = row.mV[VY];
    mMatrix[VZ][VZ] = row.mV[VZ];
}


void LLMatrix4::setFwdCol(const LLVector3 &col)
{
    mMatrix[VX][VX] = col.mV[VX];
    mMatrix[VY][VX] = col.mV[VY];
    mMatrix[VZ][VX] = col.mV[VZ];
}

void LLMatrix4::setLeftCol(const LLVector3 &col)
{
    mMatrix[VX][VY] = col.mV[VX];
    mMatrix[VY][VY] = col.mV[VY];
    mMatrix[VZ][VY] = col.mV[VZ];
}

void LLMatrix4::setUpCol(const LLVector3 &col)
{
    mMatrix[VX][VZ] = col.mV[VX];
    mMatrix[VY][VZ] = col.mV[VY];
    mMatrix[VZ][VZ] = col.mV[VZ];
}


const LLMatrix4&    LLMatrix4::setTranslation(const F32 tx, const F32 ty, const F32 tz)
{
    mMatrix[VW][VX] = tx;
    mMatrix[VW][VY] = ty;
    mMatrix[VW][VZ] = tz;
    return (*this);
}

const LLMatrix4&    LLMatrix4::setTranslation(const LLVector3 &translation)
{
    mMatrix[VW][VX] = translation.mV[VX];
    mMatrix[VW][VY] = translation.mV[VY];
    mMatrix[VW][VZ] = translation.mV[VZ];
    return (*this);
}

const LLMatrix4&    LLMatrix4::setTranslation(const LLVector4 &translation)
{
    mMatrix[VW][VX] = translation.mV[VX];
    mMatrix[VW][VY] = translation.mV[VY];
    mMatrix[VW][VZ] = translation.mV[VZ];
    return (*this);
}

// LLMatrix3 Extraction and Setting
LLMatrix3   LLMatrix4::getMat3() const
{
    LLMatrix3 retmat;

    retmat.mMatrix[0][0] = mMatrix[0][0];
    retmat.mMatrix[0][1] = mMatrix[0][1];
    retmat.mMatrix[0][2] = mMatrix[0][2];

    retmat.mMatrix[1][0] = mMatrix[1][0];
    retmat.mMatrix[1][1] = mMatrix[1][1];
    retmat.mMatrix[1][2] = mMatrix[1][2];

    retmat.mMatrix[2][0] = mMatrix[2][0];
    retmat.mMatrix[2][1] = mMatrix[2][1];
    retmat.mMatrix[2][2] = mMatrix[2][2];

    return retmat;
}

const LLMatrix4&    LLMatrix4::initMatrix(const LLMatrix3 &mat)
{
    mMatrix[0][0] = mat.mMatrix[0][0];
    mMatrix[0][1] = mat.mMatrix[0][1];
    mMatrix[0][2] = mat.mMatrix[0][2];
    mMatrix[0][3] = 0.f;

    mMatrix[1][0] = mat.mMatrix[1][0];
    mMatrix[1][1] = mat.mMatrix[1][1];
    mMatrix[1][2] = mat.mMatrix[1][2];
    mMatrix[1][3] = 0.f;

    mMatrix[2][0] = mat.mMatrix[2][0];
    mMatrix[2][1] = mat.mMatrix[2][1];
    mMatrix[2][2] = mat.mMatrix[2][2];
    mMatrix[2][3] = 0.f;

    mMatrix[3][0] = 0.f;
    mMatrix[3][1] = 0.f;
    mMatrix[3][2] = 0.f;
    mMatrix[3][3] = 1.f;
    return (*this);
}

const LLMatrix4&    LLMatrix4::initMatrix(const LLMatrix3 &mat, const LLVector4 &translation)
{
    mMatrix[0][0] = mat.mMatrix[0][0];
    mMatrix[0][1] = mat.mMatrix[0][1];
    mMatrix[0][2] = mat.mMatrix[0][2];
    mMatrix[0][3] = 0.f;

    mMatrix[1][0] = mat.mMatrix[1][0];
    mMatrix[1][1] = mat.mMatrix[1][1];
    mMatrix[1][2] = mat.mMatrix[1][2];
    mMatrix[1][3] = 0.f;

    mMatrix[2][0] = mat.mMatrix[2][0];
    mMatrix[2][1] = mat.mMatrix[2][1];
    mMatrix[2][2] = mat.mMatrix[2][2];
    mMatrix[2][3] = 0.f;

    mMatrix[3][0] = translation.mV[0];
    mMatrix[3][1] = translation.mV[1];
    mMatrix[3][2] = translation.mV[2];
    mMatrix[3][3] = 1.f;
    return (*this);
}

// LLMatrix4 Operators

LLVector4 operator*(const LLVector4 &a, const LLMatrix4 &b)
{
    // Operate "to the left" on row-vector a
    return LLVector4(a.mV[VX] * b.mMatrix[VX][VX] +
                     a.mV[VY] * b.mMatrix[VY][VX] +
                     a.mV[VZ] * b.mMatrix[VZ][VX] +
                     a.mV[VW] * b.mMatrix[VW][VX],

                     a.mV[VX] * b.mMatrix[VX][VY] +
                     a.mV[VY] * b.mMatrix[VY][VY] +
                     a.mV[VZ] * b.mMatrix[VZ][VY] +
                     a.mV[VW] * b.mMatrix[VW][VY],

                     a.mV[VX] * b.mMatrix[VX][VZ] +
                     a.mV[VY] * b.mMatrix[VY][VZ] +
                     a.mV[VZ] * b.mMatrix[VZ][VZ] +
                     a.mV[VW] * b.mMatrix[VW][VZ],

                     a.mV[VX] * b.mMatrix[VX][VW] +
                     a.mV[VY] * b.mMatrix[VY][VW] +
                     a.mV[VZ] * b.mMatrix[VZ][VW] +
                     a.mV[VW] * b.mMatrix[VW][VW]);
}

LLVector4 rotate_vector(const LLVector4 &a, const LLMatrix4 &b)
{
    // Rotates but does not translate
    // Operate "to the left" on row-vector a
    LLVector4   vec;
    vec.mV[VX] = a.mV[VX] * b.mMatrix[VX][VX] +
                 a.mV[VY] * b.mMatrix[VY][VX] +
                 a.mV[VZ] * b.mMatrix[VZ][VX];

    vec.mV[VY] = a.mV[VX] * b.mMatrix[VX][VY] +
                 a.mV[VY] * b.mMatrix[VY][VY] +
                 a.mV[VZ] * b.mMatrix[VZ][VY];

    vec.mV[VZ] = a.mV[VX] * b.mMatrix[VX][VZ] +
                 a.mV[VY] * b.mMatrix[VY][VZ] +
                 a.mV[VZ] * b.mMatrix[VZ][VZ];

//  vec.mV[VW] = a.mV[VX] * b.mMatrix[VX][VW] +
//               a.mV[VY] * b.mMatrix[VY][VW] +
//               a.mV[VZ] * b.mMatrix[VZ][VW] +
    vec.mV[VW] = a.mV[VW];
    return vec;
}

LLVector3 rotate_vector(const LLVector3 &a, const LLMatrix4 &b)
{
    // Rotates but does not translate
    // Operate "to the left" on row-vector a
    LLVector3   vec;
    vec.mV[VX] = a.mV[VX] * b.mMatrix[VX][VX] +
                 a.mV[VY] * b.mMatrix[VY][VX] +
                 a.mV[VZ] * b.mMatrix[VZ][VX];

    vec.mV[VY] = a.mV[VX] * b.mMatrix[VX][VY] +
                 a.mV[VY] * b.mMatrix[VY][VY] +
                 a.mV[VZ] * b.mMatrix[VZ][VY];

    vec.mV[VZ] = a.mV[VX] * b.mMatrix[VX][VZ] +
                 a.mV[VY] * b.mMatrix[VY][VZ] +
                 a.mV[VZ] * b.mMatrix[VZ][VZ];
    return vec;
}

bool operator==(const LLMatrix4 &a, const LLMatrix4 &b)
{
    U32     i, j;
    for (i = 0; i < NUM_VALUES_IN_MAT4; i++)
    {
        for (j = 0; j < NUM_VALUES_IN_MAT4; j++)
        {
            if (a.mMatrix[j][i] != b.mMatrix[j][i])
                return false;
        }
    }
    return true;
}

bool operator!=(const LLMatrix4 &a, const LLMatrix4 &b)
{
    U32     i, j;
    for (i = 0; i < NUM_VALUES_IN_MAT4; i++)
    {
        for (j = 0; j < NUM_VALUES_IN_MAT4; j++)
        {
            if (a.mMatrix[j][i] != b.mMatrix[j][i])
                return true;
        }
    }
    return false;
}

bool operator<(const LLMatrix4& a, const LLMatrix4 &b)
{
    U32     i, j;
    for (i = 0; i < NUM_VALUES_IN_MAT4; i++)
    {
        for (j = 0; j < NUM_VALUES_IN_MAT4; j++)
        {
            if (a.mMatrix[i][j] != b.mMatrix[i][j])
            {
                return a.mMatrix[i][j] < b.mMatrix[i][j];
            }
        }
    }

    return false;
}

const LLMatrix4& operator*=(LLMatrix4 &a, F32 k)
{
    U32     i, j;
    for (i = 0; i < NUM_VALUES_IN_MAT4; i++)
    {
        for (j = 0; j < NUM_VALUES_IN_MAT4; j++)
        {
            a.mMatrix[j][i] *= k;
        }
    }
    return a;
}

std::ostream& operator<<(std::ostream& s, const LLMatrix4 &a)
{
    s << "{ "
        << a.mMatrix[VX][VX] << ", "
        << a.mMatrix[VX][VY] << ", "
        << a.mMatrix[VX][VZ] << ", "
        << a.mMatrix[VX][VW]
        << "; "
        << a.mMatrix[VY][VX] << ", "
        << a.mMatrix[VY][VY] << ", "
        << a.mMatrix[VY][VZ] << ", "
        << a.mMatrix[VY][VW]
        << "; "
        << a.mMatrix[VZ][VX] << ", "
        << a.mMatrix[VZ][VY] << ", "
        << a.mMatrix[VZ][VZ] << ", "
        << a.mMatrix[VZ][VW]
        << "; "
        << a.mMatrix[VW][VX] << ", "
        << a.mMatrix[VW][VY] << ", "
        << a.mMatrix[VW][VZ] << ", "
        << a.mMatrix[VW][VW]
      << " }";
    return s;
}

LLSD LLMatrix4::getValue() const
{
    LLSD ret;

    ret[0] = mMatrix[0][0];
    ret[1] = mMatrix[0][1];
    ret[2] = mMatrix[0][2];
    ret[3] = mMatrix[0][3];

    ret[4] = mMatrix[1][0];
    ret[5] = mMatrix[1][1];
    ret[6] = mMatrix[1][2];
    ret[7] = mMatrix[1][3];

    ret[8] = mMatrix[2][0];
    ret[9] = mMatrix[2][1];
    ret[10] = mMatrix[2][2];
    ret[11] = mMatrix[2][3];

    ret[12] = mMatrix[3][0];
    ret[13] = mMatrix[3][1];
    ret[14] = mMatrix[3][2];
    ret[15] = mMatrix[3][3];

    return ret;
}

void LLMatrix4::setValue(const LLSD& data)
{
    mMatrix[0][0] = (F32)data[0].asReal();
    mMatrix[0][1] = (F32)data[1].asReal();
    mMatrix[0][2] = (F32)data[2].asReal();
    mMatrix[0][3] = (F32)data[3].asReal();

    mMatrix[1][0] = (F32)data[4].asReal();
    mMatrix[1][1] = (F32)data[5].asReal();
    mMatrix[1][2] = (F32)data[6].asReal();
    mMatrix[1][3] = (F32)data[7].asReal();

    mMatrix[2][0] = (F32)data[8].asReal();
    mMatrix[2][1] = (F32)data[9].asReal();
    mMatrix[2][2] = (F32)data[10].asReal();
    mMatrix[2][3] = (F32)data[11].asReal();

    mMatrix[3][0] = (F32)data[12].asReal();
    mMatrix[3][1] = (F32)data[13].asReal();
    mMatrix[3][2] = (F32)data[14].asReal();
    mMatrix[3][3] = (F32)data[15].asReal();
}