/**
 * @file llplane.h
 *
 * $LicenseInfo:firstyear=2001&license=viewerlgpl$
 * 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
 * $/LicenseInfo$
 */

#ifndef LL_LLPLANE_H
#define LL_LLPLANE_H

#include "v3math.h"
#include "v4math.h"

// A simple way to specify a plane is to give its normal,
// and it's nearest approach to the origin.
//
// Given the equation for a plane : A*x + B*y + C*z + D = 0
// The plane normal = [A, B, C]
// The closest approach = D / sqrt(A*A + B*B + C*C)


LL_ALIGN_PREFIX(16)
class LLPlane
{
public:

    // Constructors
    LLPlane() {}; // no default constructor
    LLPlane(const LLVector3 &p0, F32 d) { setVec(p0, d); }
    LLPlane(const LLVector3 &p0, const LLVector3 &n) { setVec(p0, n); }
    inline void setVec(const LLVector3 &p0, F32 d) { mV.set(p0[0], p0[1], p0[2], d); }

    // Set
    inline void setVec(const LLVector3 &p0, const LLVector3 &n)
    {
        F32 d = -(p0 * n);
        setVec(n, d);
    }
    inline void setVec(const LLVector3 &p0, const LLVector3 &p1, const LLVector3 &p2)
    {
        LLVector3 u, v, w;
        u = p1 - p0;
        v = p2 - p0;
        w = u % v;
        w.normVec();
        F32 d = -(w * p0);
        setVec(w, d);
    }

    inline LLPlane& operator=(const LLVector4& v2) {  mV.set(v2[0],v2[1],v2[2],v2[3]); return *this;}

    inline LLPlane& operator=(const LLVector4a& v2) {  mV.set(v2[0],v2[1],v2[2],v2[3]); return *this;}

    inline void set(const LLPlane& p2) { mV = p2.mV; }

    //
    F32 dist(const LLVector3 &v2) const { return mV[0]*v2[0] + mV[1]*v2[1] + mV[2]*v2[2] + mV[3]; }

    inline LLSimdScalar dot3(const LLVector4a& b) const { return mV.dot3(b); }

    // Read-only access a single float in this vector. Do not use in proximity to any function call that manipulates
    // the data at the whole vector level or you will incur a substantial penalty. Consider using the splat functions instead
    inline F32 operator[](const S32 idx) const { return mV[idx]; }

    // preferable when index is known at compile time
    template <int N> LL_FORCE_INLINE void getAt(LLSimdScalar& v) const { v = mV.getScalarAt<N>(); }

    // reset the vector to 0, 0, 0, 1
    inline void clear() { mV.set(0, 0, 0, 1); }

    inline void getVector3(LLVector3& vec) const { vec.set(mV[0], mV[1], mV[2]); }

    // Retrieve the mask indicating which of the x, y, or z axis are greater or equal to zero.
    inline U8 calcPlaneMask()
    {
        return mV.greaterEqual(LLVector4a::getZero()).getGatheredBits() & LLVector4Logical::MASK_XYZ;
    }

    //check if two planes are nearly same
    bool equal(const LLPlane& p) const
    {
        return mV.equals4(p.mV);
    }

private:
    LLVector4a mV;
} LL_ALIGN_POSTFIX(16);



#endif // LL_LLPLANE_H