/**
 * @file llregionhandle.h
 * @brief Routines for converting positions to/from region handles.
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * 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_LLREGIONHANDLE_H
#define LL_LLREGIONHANDLE_H

#include "indra_constants.h"
#include "v3math.h"
#include "v3dmath.h"

inline U64 to_region_handle(const U32 x_origin, const U32 y_origin)
{
    U64 region_handle;
    region_handle =  ((U64)x_origin) << 32;
    region_handle |= (U64) y_origin;
    return region_handle;
}

inline U64 to_region_handle(const LLVector3d& pos_global)
{
    U32 global_x = (U32)pos_global.mdV[VX];
    global_x -= global_x % 256;

    U32 global_y = (U32)pos_global.mdV[VY];
    global_y -= global_y % 256;

    return to_region_handle(global_x, global_y);
}

inline U64 to_region_handle_global(const F32 x_global, const F32 y_global)
{
    // Round down to the nearest origin
    U32 x_origin = (U32)x_global;
    x_origin -= x_origin % REGION_WIDTH_U32;
    U32 y_origin = (U32)y_global;
    y_origin -= y_origin % REGION_WIDTH_U32;
    U64 region_handle;
    region_handle =  ((U64)x_origin) << 32;
    region_handle |= (U64) y_origin;
    return region_handle;
}

inline bool to_region_handle(const F32 x_pos, const F32 y_pos, U64 *region_handle)
{
    U32 x_int, y_int;
    if (x_pos < 0.f)
    {
//      LL_WARNS() << "to_region_handle:Clamping negative x position " << x_pos << " to zero!" << LL_ENDL;
        return false;
    }
    else
    {
        x_int = (U32)ll_round(x_pos);
    }
    if (y_pos < 0.f)
    {
//      LL_WARNS() << "to_region_handle:Clamping negative y position " << y_pos << " to zero!" << LL_ENDL;
        return false;
    }
    else
    {
        y_int = (U32)ll_round(y_pos);
    }
    *region_handle = to_region_handle(x_int, y_int);
    return true;
}

// stuff the word-frame XY location of sim's SouthWest corner in x_pos, y_pos
inline void from_region_handle(const U64 &region_handle, F32 *x_pos, F32 *y_pos)
{
    *x_pos = (F32)((U32)(region_handle >> 32));
    *y_pos = (F32)((U32)(region_handle & 0xFFFFFFFF));
}

// stuff the word-frame XY location of sim's SouthWest corner in x_pos, y_pos
inline void from_region_handle(const U64 &region_handle, U32 *x_pos, U32 *y_pos)
{
    *x_pos = ((U32)(region_handle >> 32));
    *y_pos = ((U32)(region_handle & 0xFFFFFFFF));
}

// return the word-frame XY location of sim's SouthWest corner in LLVector3d
inline LLVector3d from_region_handle(const U64 &region_handle)
{
    return LLVector3d(((U32)(region_handle >> 32)), (U32)(region_handle & 0xFFFFFFFF), 0.f);
}

// grid-based region handle encoding. pass in a grid position
// (eg: 1000,1000) and this will return the region handle.
inline U64 grid_to_region_handle(const U32 grid_x, const U32 grid_y)
{
    return to_region_handle(grid_x * REGION_WIDTH_UNITS,
                            grid_y * REGION_WIDTH_UNITS);
}

inline void grid_from_region_handle(const U64& region_handle, U32* grid_x, U32* grid_y)
{
    from_region_handle(region_handle, grid_x, grid_y);
    *grid_x /= REGION_WIDTH_UNITS;
    *grid_y /= REGION_WIDTH_UNITS;
}

#endif