/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
Copyright (C) 2000-2009 Darklegion Development

This file is part of Tremulous.

Tremulous 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.

Tremulous 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 Tremulous; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

// cg_marks.c -- wall marks


#include "cg_local.h"

/*
===================================================================

MARK POLYS

===================================================================
*/


markPoly_t  cg_activeMarkPolys;     // double linked list
markPoly_t  *cg_freeMarkPolys;      // single linked list
markPoly_t  cg_markPolys[ MAX_MARK_POLYS ];
static int  markTotal;

/*
===================
CG_InitMarkPolys

This is called at startup and for tournement restarts
===================
*/
void CG_InitMarkPolys( void )
{
  int   i;

  memset( cg_markPolys, 0, sizeof( cg_markPolys ) );

  cg_activeMarkPolys.nextMark = &cg_activeMarkPolys;
  cg_activeMarkPolys.prevMark = &cg_activeMarkPolys;
  cg_freeMarkPolys = cg_markPolys;

  for( i = 0; i < MAX_MARK_POLYS - 1; i++ )
    cg_markPolys[ i ].nextMark = &cg_markPolys[ i + 1 ];
}


/*
==================
CG_FreeMarkPoly
==================
*/
void CG_FreeMarkPoly( markPoly_t *le )
{
  if( !le->prevMark )
    CG_Error( "CG_FreeLocalEntity: not active" );

  // remove from the doubly linked active list
  le->prevMark->nextMark = le->nextMark;
  le->nextMark->prevMark = le->prevMark;

  // the free list is only singly linked
  le->nextMark = cg_freeMarkPolys;
  cg_freeMarkPolys = le;
}

/*
===================
CG_AllocMark

Will allways succeed, even if it requires freeing an old active mark
===================
*/
markPoly_t *CG_AllocMark( void )
{
  markPoly_t  *le;
  int         time;

  if( !cg_freeMarkPolys )
  {
    // no free entities, so free the one at the end of the chain
    // remove the oldest active entity
    time = cg_activeMarkPolys.prevMark->time;

    while( cg_activeMarkPolys.prevMark && time == cg_activeMarkPolys.prevMark->time )
      CG_FreeMarkPoly( cg_activeMarkPolys.prevMark );
  }

  le = cg_freeMarkPolys;
  cg_freeMarkPolys = cg_freeMarkPolys->nextMark;

  memset( le, 0, sizeof( *le ) );

  // link into the active list
  le->nextMark = cg_activeMarkPolys.nextMark;
  le->prevMark = &cg_activeMarkPolys;
  cg_activeMarkPolys.nextMark->prevMark = le;
  cg_activeMarkPolys.nextMark = le;
  return le;
}



/*
=================
CG_ImpactMark

origin should be a point within a unit of the plane
dir should be the plane normal

temporary marks will not be stored or randomly oriented, but immediately
passed to the renderer.
=================
*/
#define MAX_MARK_FRAGMENTS  128
#define MAX_MARK_POINTS   384

void CG_ImpactMark( qhandle_t markShader, const vec3_t origin, const vec3_t dir,
                    float orientation, float red, float green, float blue, float alpha,
                    qboolean alphaFade, float radius, qboolean temporary )
{
  vec3_t          axis[ 3 ];
  float           texCoordScale;
  vec3_t          originalPoints[ 4 ];
  byte            colors[ 4 ];
  int             i, j;
  int             numFragments;
  markFragment_t  markFragments[ MAX_MARK_FRAGMENTS ], *mf;
  vec3_t          markPoints[ MAX_MARK_POINTS ];
  vec3_t          projection;

  if( !cg_addMarks.integer )
    return;

  if( radius <= 0 )
    CG_Error( "CG_ImpactMark called with <= 0 radius" );

  //if ( markTotal >= MAX_MARK_POLYS ) {
  //  return;
  //}

  // create the texture axis
  VectorNormalize2( dir, axis[ 0 ] );
  PerpendicularVector( axis[ 1 ], axis[ 0 ] );
  RotatePointAroundVector( axis[ 2 ], axis[ 0 ], axis[ 1 ], orientation );
  CrossProduct( axis[ 0 ], axis[ 2 ], axis[ 1 ] );

  texCoordScale = 0.5 * 1.0 / radius;

  // create the full polygon
  for( i = 0; i < 3; i++ )
  {
    originalPoints[ 0 ][ i ] = origin[ i ] - radius * axis[ 1 ][ i ] - radius * axis[ 2 ][ i ];
    originalPoints[ 1 ][ i ] = origin[ i ] + radius * axis[ 1 ][ i ] - radius * axis[ 2 ][ i ];
    originalPoints[ 2 ][ i ] = origin[ i ] + radius * axis[ 1 ][ i ] + radius * axis[ 2 ][ i ];
    originalPoints[ 3 ][ i ] = origin[ i ] - radius * axis[ 1 ][ i ] + radius * axis[ 2 ][ i ];
  }

  // get the fragments
  VectorScale( dir, -20, projection );
  numFragments = trap_CM_MarkFragments( 4, (void *)originalPoints,
          projection, MAX_MARK_POINTS, markPoints[ 0 ],
          MAX_MARK_FRAGMENTS, markFragments );

  colors[ 0 ] = red * 255;
  colors[ 1 ] = green * 255;
  colors[ 2 ] = blue * 255;
  colors[ 3 ] = alpha * 255;

  for( i = 0, mf = markFragments; i < numFragments; i++, mf++ )
  {
    polyVert_t  *v;
    polyVert_t  verts[ MAX_VERTS_ON_POLY ];
    markPoly_t  *mark;

    // we have an upper limit on the complexity of polygons
    // that we store persistantly
    if( mf->numPoints > MAX_VERTS_ON_POLY )
      mf->numPoints = MAX_VERTS_ON_POLY;

    for( j = 0, v = verts; j < mf->numPoints; j++, v++ )
    {
      vec3_t    delta;

      VectorCopy( markPoints[ mf->firstPoint + j ], v->xyz );

      VectorSubtract( v->xyz, origin, delta );
      v->st[ 0 ] = 0.5 + DotProduct( delta, axis[ 1 ] ) * texCoordScale;
      v->st[ 1 ] = 0.5 + DotProduct( delta, axis[ 2 ] ) * texCoordScale;
      *(int *)v->modulate = *(int *)colors;
    }

    // if it is a temporary (shadow) mark, add it immediately and forget about it
    if( temporary )
    {
      trap_R_AddPolyToScene( markShader, mf->numPoints, verts );
      continue;
    }

    // otherwise save it persistantly
    mark = CG_AllocMark( );
    mark->time = cg.time;
    mark->alphaFade = alphaFade;
    mark->markShader = markShader;
    mark->poly.numVerts = mf->numPoints;
    mark->color[ 0 ] = red;
    mark->color[ 1 ] = green;
    mark->color[ 2 ] = blue;
    mark->color[ 3 ] = alpha;
    memcpy( mark->verts, verts, mf->numPoints * sizeof( verts[ 0 ] ) );
    markTotal++;
  }
}


/*
===============
CG_AddMarks
===============
*/
#define MARK_TOTAL_TIME   10000
#define MARK_FADE_TIME    1000

void CG_AddMarks( void )
{
  int         j;
  markPoly_t  *mp, *next;
  int         t;
  int         fade;

  if( !cg_addMarks.integer )
    return;

  mp = cg_activeMarkPolys.nextMark;
  for ( ; mp != &cg_activeMarkPolys; mp = next )
  {
    // grab next now, so if the local entity is freed we
    // still have it
    next = mp->nextMark;

    // see if it is time to completely remove it
    if( cg.time > mp->time + MARK_TOTAL_TIME )
    {
      CG_FreeMarkPoly( mp );
      continue;
    }

    // fade all marks out with time
    t = mp->time + MARK_TOTAL_TIME - cg.time;
    if( t < MARK_FADE_TIME )
    {
      fade = 255 * t / MARK_FADE_TIME;
      if( mp->alphaFade )
      {
        for( j = 0; j < mp->poly.numVerts; j++ )
          mp->verts[ j ].modulate[ 3 ] = fade;
      }
      else
      {
        for( j = 0; j < mp->poly.numVerts; j++ )
        {
          mp->verts[ j ].modulate[ 0 ] = mp->color[ 0 ] * fade;
          mp->verts[ j ].modulate[ 1 ] = mp->color[ 1 ] * fade;
          mp->verts[ j ].modulate[ 2 ] = mp->color[ 2 ] * fade;
        }
      }
    }

    trap_R_AddPolyToScene( mp->markShader, mp->poly.numVerts, mp->verts );
  }
}