/* Emacs style mode select   -*- C++ -*-
 *-----------------------------------------------------------------------------
 *
 *
 *  PrBoom a Doom port merged with LxDoom and LSDLDoom
 *  based on BOOM, a modified and improved DOOM engine
 *  Copyright (C) 1999 by
 *  id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
 *  Copyright (C) 1999-2000 by
 *  Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
 *
 *  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.
 *
 * DESCRIPTION:
 *      Rendering main loop and setup functions,
 *       utility functions (BSP, geometry, trigonometry).
 *      See tables.c, too.
 *
 *-----------------------------------------------------------------------------*/

#include "doomstat.h"
#include "w_wad.h"
#include "r_main.h"
#include "r_things.h"
#include "r_plane.h"
#include "r_bsp.h"
#include "r_draw.h"
#include "m_bbox.h"
#include "r_sky.h"
#include "v_video.h"
#include "i_system.h"
//#include "lprintf.h"
#include "st_stuff.h"
#include "rockmacros.h"

// Fineangles in the SCREENWIDTH wide window.
#define FIELDOFVIEW 2048

// killough: viewangleoffset is a legacy from the pre-v1.2 days, when Doom
// had Left/Mid/Right viewing. +/-ANG90 offsets were placed here on each
// node, by d_net.c, to set up a L/M/R session.

int   viewangleoffset;

int validcount = 1;     // increment every time a check is made
lighttable_t *fixedcolormap;
int centerx IBSS_ATTR;
int centery IBSS_ATTR;
fixed_t  centerxfrac, centeryfrac;
fixed_t   projection;
// proff 11/06/98: Added for high-res
fixed_t  projectiony;
fixed_t  viewx, viewy, viewz;
angle_t  viewangle;
fixed_t  viewcos, viewsin;
player_t *viewplayer;
extern lighttable_t **walllights;

//
// precalculated math tables
//

angle_t clipangle;

// The viewangletox[viewangle + FINEANGLES/4] lookup
// maps the visible view angles to screen X coordinates,
// flattening the arc to a flat projection plane.
// There will be many angles mapped to the same X.

int *viewangletox=0;

// The xtoviewangleangle[] table maps a screen pixel
// to the lowest viewangle that maps back to x ranges
// from clipangle to -clipangle.

angle_t xtoviewangle[MAX_SCREENWIDTH+1];   // killough 2/8/98

// killough 3/20/98: Support dynamic colormaps, e.g. deep water
// killough 4/4/98: support dynamic number of them as well

int numcolormaps;
lighttable_t *(*c_scalelight)[LIGHTLEVELS][MAXLIGHTSCALE];
lighttable_t *(*c_zlight)[LIGHTLEVELS][MAXLIGHTZ];
lighttable_t *(*scalelight)[MAXLIGHTSCALE];
lighttable_t *(*zlight)[MAXLIGHTZ];
lighttable_t *fullcolormap;
lighttable_t **colormaps;

// killough 3/20/98, 4/4/98: end dynamic colormaps

int extralight;                           // bumped light from gun blasts

void (*colfunc)(void);

//
// R_PointOnSide
// Traverse BSP (sub) tree,
//  check point against partition plane.
// Returns side 0 (front) or 1 (back).
//
// killough 5/2/98: reformatted
//

int R_PointOnSide(fixed_t x, fixed_t y, const node_t *node)
{
   if (!node->dx)
      return x <= node->x ? node->dy > 0 : node->dy < 0;

   if (!node->dy)
      return y <= node->y ? node->dx < 0 : node->dx > 0;

   x -= node->x;
   y -= node->y;

   // Try to quickly decide by looking at sign bits.
   if ((node->dy ^ node->dx ^ x ^ y) < 0)
      return (node->dy ^ x) < 0;  // (left is negative)
   return FixedMul(y, node->dx>>FRACBITS) >= FixedMul(node->dy>>FRACBITS, x);
}

// killough 5/2/98: reformatted

int R_PointOnSegSide(fixed_t x, fixed_t y, const seg_t *line)
{
   fixed_t lx = line->v1->x;
   fixed_t ly = line->v1->y;
   fixed_t ldx = line->v2->x - lx;
   fixed_t ldy = line->v2->y - ly;

   if (!ldx)
      return x <= lx ? ldy > 0 : ldy < 0;

   if (!ldy)
      return y <= ly ? ldx < 0 : ldx > 0;

   x -= lx;
   y -= ly;

   // Try to quickly decide by looking at sign bits.
   if ((ldy ^ ldx ^ x ^ y) < 0)
      return (ldy ^ x) < 0;          // (left is negative)
   return FixedMul(y, ldx>>FRACBITS) >= FixedMul(ldy>>FRACBITS, x);
}

//
// R_PointToAngle
// To get a global angle from cartesian coordinates,
//  the coordinates are flipped until they are in
//  the first octant of the coordinate system, then
//  the y (<=x) is scaled and divided by x to get a
//  tangent (slope) value which is looked up in the
//  tantoangle[] table. The +1 size of tantoangle[]
//  is to handle the case when x==y without additional
//  checking.
//
// killough 5/2/98: reformatted, cleaned up

angle_t R_PointToAngle(fixed_t x, fixed_t y)
{
   return (y -= viewy, (x -= viewx) || y) ?
          x >= 0 ?
          y >= 0 ?
          (x > y) ? tantoangle[SlopeDiv(y,x)] :                      // octant 0
       ANG90-1-tantoangle[SlopeDiv(x,y)] :                // octant 1
          x > (y = -y) ? 0-tantoangle[SlopeDiv(y,x)] :                // octant 8
       ANG270+tantoangle[SlopeDiv(x,y)] :          // octant 7
          y >= 0 ? (x = -x) > y ? ANG180-1-tantoangle[SlopeDiv(y,x)] : // octant 3
       ANG90 + tantoangle[SlopeDiv(x,y)] :    // octant 2
          (x = -x) > (y = -y) ? ANG180+tantoangle[ SlopeDiv(y,x)] :  // octant 4
       ANG270-1-tantoangle[SlopeDiv(x,y)] : // octant 5
          0;
}

angle_t R_PointToAngle2(fixed_t viewx, fixed_t viewy, fixed_t x, fixed_t y)
{
   return (y -= viewy, (x -= viewx) || y) ?
          x >= 0 ?
          y >= 0 ?
          (x > y) ? tantoangle[SlopeDiv(y,x)] :                      // octant 0
       ANG90-1-tantoangle[SlopeDiv(x,y)] :                // octant 1
          x > (y = -y) ? 0-tantoangle[SlopeDiv(y,x)] :                // octant 8
       ANG270+tantoangle[SlopeDiv(x,y)] :          // octant 7
          y >= 0 ? (x = -x) > y ? ANG180-1-tantoangle[SlopeDiv(y,x)] : // octant 3
       ANG90 + tantoangle[SlopeDiv(x,y)] :    // octant 2
          (x = -x) > (y = -y) ? ANG180+tantoangle[ SlopeDiv(y,x)] :  // octant 4
       ANG270-1-tantoangle[SlopeDiv(x,y)] : // octant 5
          0;
}

//
// R_InitTextureMapping
//
// killough 5/2/98: reformatted

static void R_InitTextureMapping (void)
{
   register int i,x;
   fixed_t focallength;

   // Use tangent table to generate viewangletox:
   //  viewangletox will give the next greatest x
   //  after the view angle.
   //
   // Calc focallength
   //  so FIELDOFVIEW angles covers SCREENWIDTH.

   if(viewangletox==NULL)
      viewangletox=malloc(sizeof(int)*FINEANGLES/2);

   focallength = FixedDiv(centerxfrac, finetangent[FINEANGLES/4+FIELDOFVIEW/2]);

   for (i=0 ; i<FINEANGLES/2 ; i++)
   {
      int t;
      if (finetangent[i] > FRACUNIT*2)
         t = -1;
      else
         if (finetangent[i] < -FRACUNIT*2)
            t = viewwidth+1;
         else
         {
            t = FixedMul(finetangent[i], focallength);
            t = (centerxfrac - t + FRACUNIT-1) >> FRACBITS;
            if (t < -1)
               t = -1;
            else
               if (t > viewwidth+1)
                  t = viewwidth+1;
         }
      viewangletox[i] = t;
   }

   // Scan viewangletox[] to generate xtoviewangle[]:
   //  xtoviewangle will give the smallest view angle
   //  that maps to x.

   for (x=0; x<=viewwidth; x++)
   {
      for (i=0; viewangletox[i] > x; i++)
         ;
      xtoviewangle[x] = (i<<ANGLETOFINESHIFT)-ANG90;
   }

   // Take out the fencepost cases from viewangletox.
   for (i=0; i<FINEANGLES/2; i++)
      if (viewangletox[i] == -1)
         viewangletox[i] = 0;
      else
         if (viewangletox[i] == viewwidth+1)
            viewangletox[i] = viewwidth;

   clipangle = xtoviewangle[0];
}

//
// R_InitLightTables
// Only inits the zlight table,
//  because the scalelight table changes with view size.
//

#define DISTMAP 2

void R_InitLightTables (void)
{
   int i;

   // killough 4/4/98: dynamic colormaps
   c_zlight = malloc(sizeof(*c_zlight) * numcolormaps);
   c_scalelight = malloc(sizeof(*c_scalelight) * numcolormaps);

   // Calculate the light levels to use
   //  for each level / distance combination.
   for (i=0; i< LIGHTLEVELS; i++)
   {
      int j, startmap = ((LIGHTLEVELS-1-i)*2)*NUMCOLORMAPS/LIGHTLEVELS;
      for (j=0; j<MAXLIGHTZ; j++)
      {
         // CPhipps - use 320 here instead of SCREENWIDTH, otherwise hires is
         //           brighter than normal res
         int scale = FixedDiv ((320/2*FRACUNIT), (j+1)<<LIGHTZSHIFT);
         int t, level = startmap - (scale >>= LIGHTSCALESHIFT)/DISTMAP;

         if (level < 0)
            level = 0;
         else
            if (level >= NUMCOLORMAPS)
               level = NUMCOLORMAPS-1;

         // killough 3/20/98: Initialize multiple colormaps
         level *= 256;
         for (t=0; t<numcolormaps; t++)         // killough 4/4/98
            c_zlight[t][i][j] = colormaps[t] + level;
      }
   }
}

//
// R_SetViewSize
// Do not really change anything here,
//  because it might be in the middle of a refresh.
// The change will take effect next refresh.
//

boolean setsizeneeded;
int     setblocks;

void R_SetViewSize(int blocks)
{
   setsizeneeded = true;
   setblocks = blocks;
}

//
// R_ExecuteSetViewSize
//

void R_ExecuteSetViewSize (void)
{
   int i;

   setsizeneeded = false;

   if (setblocks == 11)
   {
      scaledviewwidth = SCREENWIDTH;
      viewheight = SCREENHEIGHT;
   }
   // proff 09/24/98: Added for high-res
   else if (setblocks == 10)
   {
      scaledviewwidth = SCREENWIDTH;
      viewheight = SCREENHEIGHT-ST_SCALED_HEIGHT;
   }
   else
   {
      // proff 08/17/98: Changed for high-res
      scaledviewwidth = setblocks*SCREENWIDTH/10;
      viewheight = (setblocks*(SCREENHEIGHT-ST_SCALED_HEIGHT)/10) & ~7;
   }

   viewwidth = scaledviewwidth;

   centery = viewheight/2;
   centerx = viewwidth/2;
   centerxfrac = centerx<<FRACBITS;
   centeryfrac = centery<<FRACBITS;
   projection = centerxfrac;
   // proff 11/06/98: Added for high-res
   projectiony = ((SCREENHEIGHT * centerx * 320) / 200) / SCREENWIDTH * FRACUNIT;

   R_InitBuffer (scaledviewwidth, viewheight);

   R_InitTextureMapping();

   // psprite scales
   // proff 08/17/98: Changed for high-res
   pspritescale = FRACUNIT*viewwidth/320;
   pspriteiscale = FRACUNIT*320/viewwidth;
   // proff 11/06/98: Added for high-res
   pspriteyscale = (((SCREENHEIGHT*viewwidth)/SCREENWIDTH) << FRACBITS) / 200;

   // thing clipping
   for (i=0 ; i<viewwidth ; i++)
      screenheightarray[i] = viewheight;

   // planes
   for (i=0 ; i<viewheight ; i++)
   {   // killough 5/2/98: reformatted
      fixed_t dy = D_abs(((i-viewheight/2)<<FRACBITS)+FRACUNIT/2);
      // proff 08/17/98: Changed for high-res
      yslope[i] = FixedDiv(projectiony, dy);
   }

   for (i=0 ; i<viewwidth ; i++)
   {
      fixed_t cosadj = D_abs(finecosine[xtoviewangle[i]>>ANGLETOFINESHIFT]);
      distscale[i] = FixedDiv(FRACUNIT,cosadj);
   }

   // Calculate the light levels to use
   //  for each level / scale combination.
   for (i=0; i<LIGHTLEVELS; i++)
   {
      int j, startmap = ((LIGHTLEVELS-1-i)*2)*NUMCOLORMAPS/LIGHTLEVELS;
      for (j=0 ; j<MAXLIGHTSCALE ; j++)
      {
         int t, level = startmap - j*320/viewwidth/DISTMAP;

         if (level < 0)
            level = 0;

         if (level >= NUMCOLORMAPS)
            level = NUMCOLORMAPS-1;

         // killough 3/20/98: initialize multiple colormaps
         level *= 256;

         for (t=0; t<numcolormaps; t++)     // killough 4/4/98
            c_scalelight[t][i][j] = colormaps[t] + level;
      }
   }
}

//
// R_Init
//

extern int screenblocks;

void R_Init (void)
{
   // CPhipps - R_DrawColumn isn't constant anymore, so must
   //  initialise in code
   colfunc = R_DrawColumn;     // current column draw function
//   if (SCREENWIDTH<320)
//      I_Error("R_Init: Screenwidth(%d) < 320",SCREENWIDTH);
#if 1

   printf("\nR_LoadTrigTables: ");
   R_LoadTrigTables();
#endif

   printf("\nR_InitData: ");
   R_InitData();
   R_SetViewSize(screenblocks);
   printf("\nR_Init: R_InitPlanes ");
   R_InitPlanes();
   printf("R_InitLightTables ");
   R_InitLightTables();
   printf("R_InitSkyMap ");
   R_InitSkyMap();
   printf("R_InitTranslationsTables ");
   R_InitTranslationTables();
}

//
// R_PointInSubsector
//
// killough 5/2/98: reformatted, cleaned up

subsector_t *R_PointInSubsector(fixed_t x, fixed_t y)
{
   int nodenum = numnodes-1;
   while (!(nodenum & NF_SUBSECTOR))
      nodenum = nodes[nodenum].children[R_PointOnSide(x, y, nodes+nodenum)];
   return &subsectors[nodenum & ~NF_SUBSECTOR];
}

//
// R_SetupFrame
//

void R_SetupFrame (player_t *player)
{
   int i, cm;

   viewplayer = player;
   viewx = player->mo->x;
   viewy = player->mo->y;
   viewangle = player->mo->angle + viewangleoffset;
   extralight = player->extralight;

   viewz = player->viewz;

   viewsin = finesine[viewangle>>ANGLETOFINESHIFT];
   viewcos = finecosine[viewangle>>ANGLETOFINESHIFT];

   // killough 3/20/98, 4/4/98: select colormap based on player status

   if (player->mo->subsector->sector->heightsec != -1)
   {
      const sector_t *s = player->mo->subsector->sector->heightsec + sectors;
      cm = viewz < s->floorheight ? s->bottommap : viewz > s->ceilingheight ?
           s->topmap : s->midmap;
      if (cm < 0 || cm > numcolormaps)
         cm = 0;
   }
   else
      cm = 0;

   fullcolormap = colormaps[cm];
   zlight = c_zlight[cm];
   scalelight = c_scalelight[cm];

   if (player->fixedcolormap)
   {
      // killough 3/20/98: localize scalelightfixed (readability/optimization)
      static lighttable_t *scalelightfixed[MAXLIGHTSCALE];

      fixedcolormap = fullcolormap   // killough 3/20/98: use fullcolormap
                      + player->fixedcolormap*256*sizeof(lighttable_t);

      walllights = scalelightfixed;

      for (i=0 ; i<MAXLIGHTSCALE ; i++)
         scalelightfixed[i] = fixedcolormap;
   }
   else
      fixedcolormap = 0;

   validcount++;
}

//
// R_RenderView
//
void R_RenderPlayerView (player_t* player)
{
   R_SetupFrame (player);

   // Clear buffers.
   R_ClearClipSegs ();
   R_ClearDrawSegs ();
   R_ClearPlanes ();
   R_ClearSprites ();

   // check for new console commands.
   //    NetUpdate ();

   // The head node is the last node output.
   R_RenderBSPNode (numnodes-1);

   // Check for new console commands.
   //   NetUpdate ();

   R_DrawPlanes ();

   // Check for new console commands.
   //    NetUpdate ();

   R_DrawMasked ();

   // Check for new console commands.
   //    NetUpdate ();
}