/* 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:
 *      The actual span/column drawing functions.
 *      Here find the main potential for optimization,
 *       e.g. inline assembly, different algorithms.
 *
 *-----------------------------------------------------------------------------*/

#include "doomstat.h"
#include "w_wad.h"
#include "r_main.h"
#include "v_video.h"
#include "st_stuff.h"
#include "g_game.h"
#include "am_map.h"
//#include "lprintf.h"
#include "rockmacros.h"

//
// All drawing to the view buffer is accomplished in this file.
// The other refresh files only know about ccordinates,
//  not the architecture of the frame buffer.
// Conveniently, the frame buffer is a linear one,
//  and we need only the base address,
//  and the total size == width*height*depth/8.,
//

//byte*  viewimage;
int  viewwidth;
int  scaledviewwidth;
int  viewheight;
int  viewwindowx;
int  viewwindowy;

byte *topleft IBSS_ATTR;

// Color tables for different players,
//  translate a limited part to another
//  (color ramps used for  suit colors).
//

// CPhipps - made const*'s
const byte *tranmap IBSS_ATTR;          // translucency filter maps 256x256   // phares
const byte *main_tranmap IBSS_ATTR;     // killough 4/11/98

//
// R_DrawColumn
// Source is the top of the column to scale.
//

lighttable_t *dc_colormap IBSS_ATTR;
int     dc_x IBSS_ATTR;
int     dc_yl IBSS_ATTR;
int     dc_yh IBSS_ATTR;
fixed_t dc_iscale IBSS_ATTR;
fixed_t dc_texturemid IBSS_ATTR;
int     dc_texheight IBSS_ATTR;    // killough
const byte    *dc_source IBSS_ATTR;      // first pixel in a column (possibly virtual)


//
// A column is a vertical slice/span from a wall texture that,
//  given the DOOM style restrictions on the view orientation,
//  will always have constant z depth.
// Thus a special case loop for very fast rendering can
//  be used. It has also been used with Wolfenstein 3D.
//
void R_DrawColumn (void)
{
   int              count;
   register byte    *dest;            // killough
   register fixed_t frac;            // killough

   // leban 1/17/99:
   // removed the + 1 here, adjusted the if test, and added an increment
   // later.  this helps a compiler pipeline a bit better.  the x86
   // assembler also does this.
   count = dc_yh - dc_yl;

   // Zero length, column does not exceed a pixel.
   if (count < 0)
      return;

#ifdef RANGECHECK

   if ((unsigned)dc_x >= SCREENWIDTH
         || dc_yl < 0
         || dc_yh >= SCREENHEIGHT)
      I_Error ("R_DrawColumn: %d to %d at %d", dc_yl, dc_yh, dc_x);
#endif

   count++;

   // Framebuffer destination address.
   dest = topleft + dc_yl*SCREENWIDTH + dc_x;

   // Determine scaling,
   // which is the only mapping to be done.
#define  fracstep dc_iscale

   frac = dc_texturemid + (dc_yl-centery)*fracstep;

   // Inner loop that does the actual texture mapping,
   //  e.g. a DDA-lile scaling.
   // This is as fast as it gets.       (Yeah, right!!! -- killough)
   //
   // killough 2/1/98: more performance tuning

   if (dc_texheight == 128)
   {
      while(count--)
      {
         *dest = dc_colormap[dc_source[(frac>>FRACBITS)&127]];
         frac += fracstep;
         dest += SCREENWIDTH;
      }
   }
   else if (dc_texheight == 0)
   {
      /* cph - another special case */
      while (count--)
      {
         *dest = dc_colormap[dc_source[frac>>FRACBITS]];
         frac += fracstep;
         dest += SCREENWIDTH;
      }
   }
   else
   {
      register unsigned heightmask = dc_texheight-1; // CPhipps - specify type
      if (! (dc_texheight & heightmask) )   // power of 2 -- killough
      {
         while (count>0)   // texture height is a power of 2 -- killough
         {
            *dest = dc_colormap[dc_source[(frac>>FRACBITS) & heightmask]];
            dest += SCREENWIDTH;
            frac += fracstep;
            count--;
         }
      }
      else
      {
         heightmask++;
         heightmask <<= FRACBITS;

         if (frac < 0)
            while ((frac += heightmask) <  0)
               ;
         else
            while (frac >= (int)heightmask)
               frac -= heightmask;

         while(count>0)
         {
            // Re-map color indices from wall texture column
            //  using a lighting/special effects LUT.

            // heightmask is the Tutti-Frutti fix -- killough

            *dest = dc_colormap[dc_source[frac>>FRACBITS]];
            dest += SCREENWIDTH;
            if ((frac += fracstep) >= (int)heightmask)
               frac -= heightmask;
            count--;
         }
      }
   }
}
#undef fracstep

// Here is the version of R_DrawColumn that deals with translucent  // phares
// textures and sprites. It's identical to R_DrawColumn except      //    |
// for the spot where the color index is stuffed into *dest. At     //    V
// that point, the existing color index and the new color index
// are mapped through the TRANMAP lump filters to get a new color
// index whose RGB values are the average of the existing and new
// colors.
//
// Since we're concerned about performance, the 'translucent or
// opaque' decision is made outside this routine, not down where the
// actual code differences are.

void R_DrawTLColumn (void)
{
   int              count;
   register byte    *dest;           // killough
   register fixed_t frac;            // killough

   count = dc_yh - dc_yl + 1;

   // Zero length, column does not exceed a pixel.
   if (count <= 0)
      return;

#ifdef RANGECHECK

   if ((unsigned)dc_x >= (unsigned)SCREENWIDTH
         || dc_yl < 0
         || dc_yh >= SCREENHEIGHT)
      I_Error("R_DrawTLColumn: %i to %i at %i", dc_yl, dc_yh, dc_x);
#endif

   // Framebuffer destination address.
   dest = topleft + dc_yl*SCREENWIDTH + dc_x;

   // Determine scaling,
   //  which is the only mapping to be done.
#define  fracstep dc_iscale

   frac = dc_texturemid + (dc_yl-centery)*fracstep;

   // Inner loop that does the actual texture mapping,
   //  e.g. a DDA-lile scaling.
   // This is as fast as it gets.       (Yeah, right!!! -- killough)
   //
   // killough 2/1/98, 2/21/98: more performance tuning

   {
      register const byte *source = dc_source;
      register const lighttable_t *colormap = dc_colormap;
      register unsigned heightmask = dc_texheight-1; // CPhipps - specify type
      if (dc_texheight & heightmask)   // not a power of 2 -- killough
      {
         heightmask++;
         heightmask <<= FRACBITS;

         if (frac < 0)
            while ((frac += heightmask) <  0)
               ;
         else
            while (frac >= (int)heightmask)
               frac -= heightmask;

         do
         {
            // Re-map color indices from wall texture column
            //  using a lighting/special effects LUT.

            // heightmask is the Tutti-Frutti fix -- killough

            *dest = tranmap[(*dest<<8)+colormap[source[frac>>FRACBITS]]]; // phares
            dest += SCREENWIDTH;
            if ((frac += fracstep) >= (int)heightmask)
               frac -= heightmask;
         }
         while (--count);
      }
      else
      {
         while ((count-=2)>=0)   // texture height is a power of 2 -- killough
         {
            *dest = tranmap[(*dest<<8)+colormap[source[(frac>>FRACBITS) & heightmask]]]; // phares
            dest += SCREENWIDTH;
            frac += fracstep;
            *dest = tranmap[(*dest<<8)+colormap[source[(frac>>FRACBITS) & heightmask]]]; // phares
            dest += SCREENWIDTH;
            frac += fracstep;
         }
         if (count & 1)
            *dest = tranmap[(*dest<<8)+colormap[source[(frac>>FRACBITS) & heightmask]]]; // phares
      }
   }
}
#undef fracstep

//
// Spectre/Invisibility.
//

#define FUZZTABLE 50
// proff 08/17/98: Changed for high-res
//#define FUZZOFF (SCREENWIDTH)
#define FUZZOFF 1

static const int fuzzoffset_org[FUZZTABLE] ICONST_ATTR = {
         FUZZOFF,-FUZZOFF,FUZZOFF,-FUZZOFF,FUZZOFF,FUZZOFF,-FUZZOFF,
         FUZZOFF,FUZZOFF,-FUZZOFF,FUZZOFF,FUZZOFF,FUZZOFF,-FUZZOFF,
         FUZZOFF,FUZZOFF,FUZZOFF,-FUZZOFF,-FUZZOFF,-FUZZOFF,-FUZZOFF,
         FUZZOFF,-FUZZOFF,-FUZZOFF,FUZZOFF,FUZZOFF,FUZZOFF,FUZZOFF,-FUZZOFF,
         FUZZOFF,-FUZZOFF,FUZZOFF,FUZZOFF,-FUZZOFF,-FUZZOFF,FUZZOFF,
         FUZZOFF,-FUZZOFF,-FUZZOFF,-FUZZOFF,-FUZZOFF,FUZZOFF,FUZZOFF,
         FUZZOFF,FUZZOFF,-FUZZOFF,FUZZOFF,FUZZOFF,-FUZZOFF,FUZZOFF
      } ;

static int fuzzoffset[FUZZTABLE] IBSS_ATTR;

static int fuzzpos IBSS_ATTR = 0;

//
// Framebuffer postprocessing.
// Creates a fuzzy image by copying pixels
//  from adjacent ones to left and right.
// Used with an all black colormap, this
//  could create the SHADOW effect,
//  i.e. spectres and invisible players.
//

void R_DrawFuzzColumn(void)
{
   int      count;
   byte     *dest;
   fixed_t  frac;
   fixed_t  fracstep;

   // Adjust borders. Low...
   if (!dc_yl)
      dc_yl = 1;

   // .. and high.
   if (dc_yh == viewheight-1)
      dc_yh = viewheight - 2;

   count = dc_yh - dc_yl;

   // Zero length.
   if (count < 0)
      return;

#ifdef RANGECHECK

   if ((unsigned) dc_x >= (unsigned)SCREENWIDTH
         || dc_yl < 0
         || (unsigned)dc_yh >= (unsigned)SCREENHEIGHT)
      I_Error("R_DrawFuzzColumn: %i to %i at %i", dc_yl, dc_yh, dc_x);
#endif

   // Keep till detailshift bug in blocky mode fixed,
   //  or blocky mode removed.

   // Does not work with blocky mode.
   dest = topleft + dc_yl*SCREENWIDTH + dc_x;

   // Looks familiar.
   fracstep = dc_iscale;
   frac = dc_texturemid + (dc_yl-centery)*fracstep;

   // Looks like an attempt at dithering,
   // using the colormap #6 (of 0-31, a bit brighter than average).

   do
   {
      // Lookup framebuffer, and retrieve
      //  a pixel that is either one column
      //  left or right of the current one.
      // Add index from colormap to index.
      // killough 3/20/98: use fullcolormap instead of colormaps

      *dest = fullcolormap[6*256+dest[fuzzoffset[fuzzpos]]];

      // Some varying invisibility effects can be gotten by playing // phares
      // with this logic. For example, try                          // phares
      //                                                            // phares
      //    *dest = fullcolormap[0*256+dest[FUZZOFF]];              // phares

      // Clamp table lookup index.
      if (++fuzzpos == FUZZTABLE)
         fuzzpos = 0;

      dest += SCREENWIDTH;

      frac += fracstep;
   }
   while (count--);
}

//
// R_DrawTranslatedColumn
// Used to draw player sprites
//  with the green colorramp mapped to others.
// Could be used with different translation
//  tables, e.g. the lighter colored version
//  of the BaronOfHell, the HellKnight, uses
//  identical sprites, kinda brightened up.
//

byte *dc_translation, *translationtables;

void R_DrawTranslatedColumn (void)
{
   int      count;
   byte     *dest;
   fixed_t  frac;
   fixed_t  fracstep;

   count = dc_yh - dc_yl;
   if (count < 0)
      return;

#ifdef RANGECHECK

   if ((unsigned)dc_x >= (unsigned)SCREENWIDTH
         || dc_yl < 0
         || (unsigned)dc_yh >= (unsigned)SCREENHEIGHT)
      I_Error("R_DrawColumn: %i to %i at %i", dc_yl, dc_yh, dc_x);
#endif

   // FIXME. As above.
   dest = topleft + dc_yl*SCREENWIDTH + dc_x;

   // Looks familiar.
   fracstep = dc_iscale;
   frac = dc_texturemid + (dc_yl-centery)*fracstep;

   // Here we do an additional index re-mapping.
   do
   {
      // Translation tables are used
      //  to map certain colorramps to other ones,
      //  used with PLAY sprites.
      // Thus the "green" ramp of the player 0 sprite
      //  is mapped to gray, red, black/indigo.

      *dest = dc_colormap[dc_translation[dc_source[frac>>FRACBITS]]];
      dest += SCREENWIDTH;

      frac += fracstep;
   }
   while (count--);
}

//
// R_InitTranslationTables
// Creates the translation tables to map
//  the green color ramp to gray, brown, red.
// Assumes a given structure of the PLAYPAL.
// Could be read from a lump instead.
//

byte playernumtotrans[MAXPLAYERS];
extern lighttable_t *(*c_zlight)[LIGHTLEVELS][MAXLIGHTZ];

void R_InitTranslationTables (void)
{
   int i, j;
#define MAXTRANS 3

   byte transtocolour[MAXTRANS];

   // killough 5/2/98:
   // Remove dependency of colormaps aligned on 256-byte boundary

   if (translationtables == NULL) // CPhipps - allow multiple calls
      translationtables = Z_Malloc(256*MAXTRANS, PU_STATIC, 0);

   for (i=0; i<MAXTRANS; i++)
      transtocolour[i] = 255;

   for (i=0; i<MAXPLAYERS; i++)
   {
      byte wantcolour = mapcolor_plyr[i];
      playernumtotrans[i] = 0;
      if (wantcolour != 0x70) // Not green, would like translation
         for (j=0; j<MAXTRANS; j++)
            if (transtocolour[j] == 255)
            {
               transtocolour[j] = wantcolour;
               playernumtotrans[i] = j+1;
               break;
            }
   }

   // translate just the 16 green colors
   for (i=0; i<256; i++)
      if (i >= 0x70 && i<= 0x7f)
      {
         // CPhipps - configurable player colours
         translationtables[i] = colormaps[0][((i&0xf)<<9) + transtocolour[0]];
         translationtables[i+256] = colormaps[0][((i&0xf)<<9) + transtocolour[1]];
         translationtables[i+512] = colormaps[0][((i&0xf)<<9) + transtocolour[2]];
      }
      else  // Keep all other colors as is.
         translationtables[i]=translationtables[i+256]=translationtables[i+512]=i;
}

//
// R_DrawSpan
// With DOOM style restrictions on view orientation,
//  the floors and ceilings consist of horizontal slices
//  or spans with constant z depth.
// However, rotation around the world z axis is possible,
//  thus this mapping, while simpler and faster than
//  perspective correct texture mapping, has to traverse
//  the texture at an angle in all but a few cases.
// In consequence, flats are not stored by column (like walls),
//  and the inner loop has to step in texture space u and v.
//

int  ds_y IBSS_ATTR;
int  ds_x1 IBSS_ATTR;
int  ds_x2 IBSS_ATTR;

lighttable_t *ds_colormap IBSS_ATTR;

fixed_t ds_xfrac IBSS_ATTR;
fixed_t ds_yfrac IBSS_ATTR;
fixed_t ds_xstep IBSS_ATTR;
fixed_t ds_ystep IBSS_ATTR;

// start of a 64*64 tile image
byte *ds_source IBSS_ATTR;

void R_DrawSpan (void)
{
   register unsigned count,xfrac = ds_xfrac,yfrac = ds_yfrac;

   byte *source;
   byte *colormap;
   byte *dest;

   source = ds_source;
   colormap = ds_colormap;
   dest = topleft + ds_y*SCREENWIDTH + ds_x1;
   count = ds_x2 - ds_x1 + 1;

   while (count)
   {
      register unsigned xtemp = xfrac >> 16;
      register unsigned ytemp = yfrac >> 10;
      register unsigned spot;
      ytemp &= 4032;
      xtemp &= 63;
      spot = xtemp | ytemp;
      xfrac += ds_xstep;
      yfrac += ds_ystep;
      *dest++ = colormap[source[spot]];
      count--;
   }
}

//
// R_InitBuffer
// Creats lookup tables that avoid
//  multiplies and other hazzles
//  for getting the framebuffer address
//  of a pixel to draw.
//

void R_InitBuffer(int width, int height)
{
   int i=0;
   // Handle resize,
   //  e.g. smaller view windows
   //  with border and/or status bar.

   viewwindowx = (SCREENWIDTH-width) >> 1;

   // Same with base row offset.

   viewwindowy = width==SCREENWIDTH ? 0 : (SCREENHEIGHT-(ST_SCALED_HEIGHT-1)-height)>>1;

   topleft = d_screens[0] + viewwindowy*SCREENWIDTH + viewwindowx;

   // Preclaculate all row offsets.
   // CPhipps - merge viewwindowx into here
   for (i=0; i<FUZZTABLE; i++)
      fuzzoffset[i] = fuzzoffset_org[i]*SCREENWIDTH;
}


//
// R_FillBackScreen
// Fills the back screen with a pattern
//  for variable screen sizes
// Also draws a beveled edge.
//
// CPhipps - patch drawing updated

void R_FillBackScreen (void)
{
   int     x,y;

   if (scaledviewwidth == SCREENWIDTH)
      return;

   V_DrawBackground(gamemode == commercial ? "GRNROCK" : "FLOOR7_2", 1);

   for (x=0 ; x<scaledviewwidth ; x+=8)
      V_DrawNamePatch(viewwindowx+x,viewwindowy-8,1,"brdr_t", CR_DEFAULT, VPT_NONE);

   for (x=0 ; x<scaledviewwidth ; x+=8)
      V_DrawNamePatch(viewwindowx+x,viewwindowy+viewheight,1,"brdr_b", CR_DEFAULT, VPT_NONE);

   for (y=0 ; y<viewheight ; y+=8)
      V_DrawNamePatch(viewwindowx-8,viewwindowy+y,1,"brdr_l", CR_DEFAULT, VPT_NONE);

   for (y=0 ; y<viewheight ; y+=8)
      V_DrawNamePatch(viewwindowx+scaledviewwidth,viewwindowy+y,1,"brdr_r", CR_DEFAULT, VPT_NONE);

   // Draw beveled edge.
   V_DrawNamePatch(viewwindowx-8,viewwindowy-8,1,"brdr_tl", CR_DEFAULT, VPT_NONE);

   V_DrawNamePatch(viewwindowx+scaledviewwidth,viewwindowy-8,1,"brdr_tr", CR_DEFAULT, VPT_NONE);

   V_DrawNamePatch(viewwindowx-8,viewwindowy+viewheight,1,"brdr_bl", CR_DEFAULT, VPT_NONE);

   V_DrawNamePatch(viewwindowx+scaledviewwidth,viewwindowy+viewheight,1,"brdr_br", CR_DEFAULT, VPT_NONE);
}

//
// Copy a screen buffer.
//

void R_VideoErase(unsigned ofs, int count)
{
   memcpy(d_screens[0]+ofs, d_screens[1]+ofs, count);   // LFB copy.
}

//
// R_DrawViewBorder
// Draws the border around the view
//  for different size windows?
//

void R_DrawViewBorder(void)
{
   int top, side, ofs, i;
   // proff/nicolas 09/20/98: Added for high-res (inspired by DosDOOM)
   int side2;

   // proff/nicolas 09/20/98: Removed for high-res
   //  if (scaledviewwidth == SCREENWIDTH)
   //  return;

   // proff/nicolas 09/20/98: Added for high-res (inspired by DosDOOM)
   if ((SCREENHEIGHT != viewheight) ||
         ((automapmode & am_active) && ! (automapmode & am_overlay)))
   {
      ofs = ( SCREENHEIGHT - ST_SCALED_HEIGHT ) * SCREENWIDTH;
      side= ( SCREENWIDTH - ST_SCALED_WIDTH ) / 2;
      side2 = side * 2;

      R_VideoErase ( ofs, side );

      ofs += ( SCREENWIDTH - side );
      for ( i = 1; i < ST_SCALED_HEIGHT; i++ )
      {
         R_VideoErase ( ofs, side2 );
         ofs += SCREENWIDTH;
      }

      R_VideoErase ( ofs, side );
   }

   if ( viewheight >= ( SCREENHEIGHT - ST_SCALED_HEIGHT ))
      return; // if high-res, don't go any further!

   top = ((SCREENHEIGHT-ST_SCALED_HEIGHT)-viewheight)/2;
   side = (SCREENWIDTH-scaledviewwidth)/2;

   // copy top and one line of left side
   R_VideoErase (0, top*SCREENWIDTH+side);

   // copy one line of right side and bottom
   ofs = (viewheight+top)*SCREENWIDTH-side;
   R_VideoErase (ofs, top*SCREENWIDTH+side);

   // copy sides using wraparound
   ofs = top*SCREENWIDTH + SCREENWIDTH-side;
   side <<= 1;

   for (i=1 ; i<viewheight ; i++)
   {
      R_VideoErase (ofs, side);
      ofs += SCREENWIDTH;
   }
}