/*
Copyright (C) 1997-2001 Id Software, Inc.
Copyright (C) 2008 Andrey Nazarov

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "sw_local.h"

//static float        sky_rotate;
//static vec3_t       sky_axis;

static int          r_skyframe;
static mface_t      r_skyfaces[6];
static cplane_t     r_skyplanes[6];
static mtexinfo_t   r_skytexinfo[6];
static mvertex_t    r_skyverts[8];
static medge_t      r_skyedges[12];
static msurfedge_t  r_skysurfedges[24];

// 3dstudio environment map names
static const char       r_skysidenames[6][3] = { "rt", "bk", "lf", "ft", "up", "dn" };
static const int        r_skysideimage[6] = { 5, 2, 4, 1, 0, 3 };

// I just copied this data from a box map...
static const int box_planes[12] = {
    2,-128, 0,-128, 2,128, 1,128, 0,128, 1,-128
};
static const int box_surfedges[24] = {
    1,2,3,4,  1,5,6,7,  8,9,6,10,  2,7,9,11, 12,3,11,8,  12,10,5,4
};
static const int box_surfverts[24] = {
    0,0,0,0,  1,0,0,0,  0,0,1,0,  1,1,1,0,  0,1,1,1,  1,1,1,1
};
static const int box_edges[24] = {
    1,2, 2,3, 3,4, 4,1, 1,5, 5,6, 6,2, 7,8, 8,6, 5,7, 8,3, 7,4
};
static const int box_flags[6] = {
    0, 0, 1, 1, 1, 0
};
static const vec3_t box_axis[6][2] = {
    { {0,-1,0}, {-1,0,0} },
    { {0,1,0}, {0,0,-1} },
    { {0,-1,0}, {1,0,0} },
    { {1,0,0}, {0,0,-1} },
    { {0,-1,0}, {0,0,-1} },
    { {-1,0,0}, {0,0,-1} }
};
static const vec3_t box_verts[8] = {
    {-1,-1,-1},
    {-1,1,-1},
    {1,1,-1},
    {1,-1,-1},
    {-1,-1,1},
    {-1,1,1},
    {1,-1,1},
    {1,1,1}
};

/*
================
R_InitSkyBox
================
*/
void R_InitSkyBox( void ) {
    int i;

    for( i = 0; i < 6; i++ ) {
        r_skyplanes[i].normal[box_planes[i*2]] = 1;
        r_skyplanes[i].dist = box_planes[i*2+1];

        VectorCopy( box_axis[i][0], r_skytexinfo[i].axis[0] );
        VectorCopy( box_axis[i][1], r_skytexinfo[i].axis[1] );

        r_skyfaces[i].plane = &r_skyplanes[i];
        r_skyfaces[i].drawflags = box_flags[i] | DSURF_SKY;
        r_skyfaces[i].numsurfedges = 4;
        r_skyfaces[i].firstsurfedge = &r_skysurfedges[i*4];
        r_skyfaces[i].texinfo = &r_skytexinfo[i];
        r_skyfaces[i].texturemins[0] = -128;
        r_skyfaces[i].texturemins[1] = -128;
        r_skyfaces[i].extents[0] = 256;
        r_skyfaces[i].extents[1] = 256;
    }

    for( i = 0; i < 24; i++ ) {
        r_skysurfedges[i].edge = &r_skyedges[box_surfedges[i]-1];
        r_skysurfedges[i].vert = box_surfverts[i];
    }

    for( i = 0; i < 12; i++ ) {
        r_skyedges[i].v[0] = &r_skyverts[box_edges[i*2+0]-1];
        r_skyedges[i].v[1] = &r_skyverts[box_edges[i*2+1]-1];
        r_skyedges[i].cachededgeoffset = 0;
    }
}

/*
================
R_EmitSkyBox
================
*/
void R_EmitSkyBox( void ) {
    int i, j;
    int oldkey;

    if (insubmodel)
        return;        // submodels should never have skies
    if (r_skyframe == r_framecount)
        return;        // already set this frame

    r_skyframe = r_framecount;

    // set the eight fake vertexes
    for( i = 0; i < 8; i++ )
        for( j = 0; j < 3; j++ )
            r_skyverts[i].point[j] = r_origin[j] + box_verts[i][j]*128;

    // set the six fake planes
    for( i = 0; i < 6; i++ )
        if (box_planes[i*2+1] > 0)
            r_skyplanes[i].dist = r_origin[box_planes[i*2]]+128;
        else
            r_skyplanes[i].dist = r_origin[box_planes[i*2]]-128;

    // fix texture offsets
    for( i = 0; i < 6; i++ ) {
        r_skytexinfo[i].offset[0] = -DotProduct( r_origin, r_skytexinfo[i].axis[0] );
        r_skytexinfo[i].offset[1] = -DotProduct( r_origin, r_skytexinfo[i].axis[1] );
    }

    // emit the six faces
    oldkey = r_currentkey;
    r_currentkey = 0x7ffffff0;
    for( i = 0; i < 6; i++ ) {
        R_RenderFace( &r_skyfaces[i], 15 );
    }
    r_currentkey = oldkey;  // bsp sorting order
}

/*
============
R_SetSky
============
*/
void R_SetSky( const char *name, float rotate, vec3_t axis ) {
    int     i;
    char    path[MAX_QPATH];
    image_t *image;

//    sky_rotate = rotate;
//    VectorCopy( axis, sky_axis );

    for( i = 0; i < 6; i++ ) {
        Q_concat( path, sizeof( path ), "env/", name,
            r_skysidenames[r_skysideimage[i]], ".pcx", NULL );
        image = IMG_Find( path, it_sky );
        if( !image ) {
            image = r_notexture;
        }
        r_skytexinfo[i].image = image;
    }
}