// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id: R_draw.c,v 1.2 2000/04/26 20:00:03 proff_fs Exp $
//
//  PRBOOM/GLBOOM (C) Florian 'Proff' Schulze (florian.proff.schulze@gmx.net)
//  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
//
//  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.
//
//-----------------------------------------------------------------------------

static const char
rcsid[] = "$Id: R_draw.c,v 1.2 2000/04/26 20:00:03 proff_fs Exp $";

#include "doomstat.h"
#include "w_wad.h"
#include "r_main.h"
#include "v_video.h"
#include "m_menu.h"
#include "st_stuff.h"

#define MAXWIDTH  MAX_SCREENWIDTH          /* kilough 2/8/98 */
#define MAXHEIGHT MAX_SCREENHEIGHT

//
// 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 *ylookup[MAXHEIGHT]; 
int  columnofs[MAXWIDTH]; 

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

byte translations[3][256];
 
byte *tranmap;          // translucency filter maps 256x256   // phares 
// proff 11/19/98: main_tranmap now contains 3 tranmaps
// at 0         the first one,  default 25% TRANMAP_POS_1
// at 256*256   the second one, default 66% TRANMAP_POS_2
// at 256*256*2 the third one,  default 75% TRANMAP_POS_3
byte *main_tranmap;     // killough 4/11/98

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

lighttable_t *dc_colormap; 
int     dc_x; 
int     dc_yl; 
int     dc_yh; 
fixed_t dc_iscale; 
fixed_t dc_texturemid;
int     dc_texheight;    // killough
byte    *dc_source;      // 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.
// 

#ifdef GL_DOOM
// proff 11/99: not needed in OpenGL
void R_DrawColumn (void)
{
}

// proff: This is in drawasm.nas
// proff 06/30/98: I forgot NOASM
#elif !defined(DJGPP) && !defined(_WIN32) || defined(NOASM)
//#ifndef DJGPP      // killough 2/15/98

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

  count = dc_yh - dc_yl + 1; 

  if (count <= 0)    // Zero length, column does not exceed a pixel.
    return; 
                                 
#ifdef RANGECHECK 
  if ((unsigned)dc_x >= SCREENWIDTH
      || dc_yl < 0
      || dc_yh >= SCREENHEIGHT) 
    I_Error ("R_DrawColumn: %i to %i at %i", dc_yl, dc_yh, dc_x); 
#endif 

  // Framebuffer destination address.
  // Use ylookup LUT to avoid multiply with ScreenWidth.
  // Use columnofs LUT for subwindows? 

  dest = ylookup[dc_yl] + columnofs[dc_x];  

  // Determine scaling, which is the only mapping to be done.

  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

  {
    register const byte *source = dc_source;            
    register const lighttable_t *colormap = dc_colormap; 
    register heightmask = dc_texheight-1;
    if (dc_texheight & heightmask)   // not a power of 2 -- killough
      {
        heightmask++;
        heightmask <<= FRACBITS;
          
        if (frac < 0)
          while ((frac += heightmask) <  0);
        else
          while (frac >= 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 = colormap[source[frac>>FRACBITS]];
            dest += SCREENWIDTH; 
            if ((frac += fracstep) >= heightmask)
              frac -= heightmask;
          } 
        while (--count);
      }
    else
      {
        while ((count-=2)>=0)   // texture height is a power of 2 -- killough
          {
            *dest = colormap[source[(frac>>FRACBITS) & heightmask]];
            dest += SCREENWIDTH; 
            frac += fracstep;
            *dest = colormap[source[(frac>>FRACBITS) & heightmask]];
            dest += SCREENWIDTH; 
            frac += fracstep;
          }
        if (count & 1)
          *dest = colormap[source[(frac>>FRACBITS) & heightmask]];
      }
  }
} 

#endif

// 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.

//#if !defined(DJGPP) && !defined(_WIN32) || defined(NOASM)
// proff: In Win32 with VC50 it seems that R_DrawTLColumn is faster in C than in ASM
#ifndef DJGPP      // killough 2/21/98: converted to x86 asm

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

  count = dc_yh - dc_yl + 1; 

  // 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: %i to %i at %i", dc_yl, dc_yh, dc_x); 
#endif 

  // Framebuffer destination address.
  // Use ylookup LUT to avoid multiply with ScreenWidth.
  // Use columnofs LUT for subwindows? 

  dest = ylookup[dc_yl] + columnofs[dc_x];  
  
  // Determine scaling,
  //  which is the only mapping to be done.

  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 heightmask = dc_texheight-1;
    if (dc_texheight & heightmask)   // not a power of 2 -- killough
      {
        heightmask++;
        heightmask <<= FRACBITS;
          
        if (frac < 0)
          while ((frac += heightmask) <  0);
        else
          while (frac >= 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) >= 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
      }
  }
} 

#endif  // killough 2/21/98: converted to x86 asm

//
// Spectre/Invisibility.
//

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

static const int fuzzoffset[FUZZTABLE] = {
  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 fuzzpos = 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 >= SCREENWIDTH
      || dc_yl < 0 
      || dc_yh >= 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 = ylookup[dc_yl] + columnofs[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 >= SCREENWIDTH
      || dc_yl < 0
      || dc_yh >= SCREENHEIGHT)
    I_Error ( "R_DrawColumn: %i to %i at %i",
              dc_yl, dc_yh, dc_x);
#endif 

  // FIXME. As above.
  dest = ylookup[dc_yl] + columnofs[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.
//

void R_InitTranslationTables (void)
{
  int i;
        
  // killough 5/2/98:
  // Remove dependency of colormaps aligned on 256-byte boundary

  translationtables = Z_Malloc(256*3, PU_STATIC, 0);
    
  // translate just the 16 green colors
  for (i=0; i<256; i++)
    if (i >= 0x70 && i<= 0x7f)
      {   // map green ramp to gray, brown, red
        translationtables[i] = 0x60 + (i&0xf);
        translationtables [i+256] = 0x40 + (i&0xf);
        translationtables [i+512] = 0x20 + (i&0xf);
      }
    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; 
int  ds_x1; 
int  ds_x2;

lighttable_t *ds_colormap; 

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

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

//#if !defined(DJGPP) && !defined(_WIN32) || defined(NOASM)
// proff: In Win32 with VC50 it seems that R_DrawSan is faster in C than in ASM
#ifndef DJGPP      // killough 2/15/98

// proff 11/18/98: Added faster R_DrawSpan

#ifdef _WIN32

void R_DrawSpan (void) 
{ 
  register unsigned position;
  unsigned step;

  register byte *dest;
    
  unsigned count;
  unsigned spot; 
                
  position = ((ds_xfrac<<10)&0xffff0000) | ((ds_yfrac>>6)&0xffff);
  step = ((ds_xstep<<10)&0xffff0000) | ((ds_ystep>>6)&0xffff);
                
  dest = ylookup[ds_y] + columnofs[ds_x1];       
  count = ds_x2 - ds_x1 + 1; 
        
  while (count >= 8)
    { 
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[0] = ds_colormap[ds_source[spot]]; 

      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[1] = ds_colormap[ds_source[spot]]; 
        
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[2] = ds_colormap[ds_source[spot]]; 
        
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[3] = ds_colormap[ds_source[spot]]; 
                
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[4] = ds_colormap[ds_source[spot]]; 

      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[5] = ds_colormap[ds_source[spot]]; 
        
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[6] = ds_colormap[ds_source[spot]]; 
        
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[7] = ds_colormap[ds_source[spot]]; 
                
      dest += 8;
      count -= 8;
    } 

  while (count >= 4)
    { 
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[0] = ds_colormap[ds_source[spot]]; 

      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[1] = ds_colormap[ds_source[spot]]; 
        
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[2] = ds_colormap[ds_source[spot]]; 
        
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      dest[3] = ds_colormap[ds_source[spot]]; 
                
      dest += 4;
      count -= 4;
    } 

  while (count)
    { 
      spot = (position>>4) & 4032;
      spot = (position>>26) | spot;
      position += step;
      *dest++ = ds_colormap[ds_source[spot]]; 
      count--;
    } 
} 

#else //_WIN32

void R_DrawSpan (void) 
{ 
  register unsigned position;
  unsigned step;

  byte *source;
  byte *colormap;
  byte *dest;
    
  unsigned count;
  unsigned spot; 
  unsigned xtemp;
  unsigned ytemp;
                
  position = ((ds_xfrac<<10)&0xffff0000) | ((ds_yfrac>>6)&0xffff);
  step = ((ds_xstep<<10)&0xffff0000) | ((ds_ystep>>6)&0xffff);
                
  source = ds_source;
  colormap = ds_colormap;
  dest = ylookup[ds_y] + columnofs[ds_x1];       
  count = ds_x2 - ds_x1 + 1; 
        
  while (count >= 4)
    { 
      ytemp = position>>4;
      ytemp = ytemp & 4032;
      xtemp = position>>26;
      spot = xtemp | ytemp;
      position += step;
      dest[0] = colormap[source[spot]]; 

      ytemp = position>>4;
      ytemp = ytemp & 4032;
      xtemp = position>>26;
      spot = xtemp | ytemp;
      position += step;
      dest[1] = colormap[source[spot]];
        
      ytemp = position>>4;
      ytemp = ytemp & 4032;
      xtemp = position>>26;
      spot = xtemp | ytemp;
      position += step;
      dest[2] = colormap[source[spot]];
        
      ytemp = position>>4;
      ytemp = ytemp & 4032;
      xtemp = position>>26;
      spot = xtemp | ytemp;
      position += step;
      dest[3] = colormap[source[spot]]; 
                
      dest += 4;
      count -= 4;
    } 

  while (count)
    { 
      ytemp = position>>4;
      ytemp = ytemp & 4032;
      xtemp = position>>26;
      spot = xtemp | ytemp;
      position += step;
      *dest++ = colormap[source[spot]]; 
      count--;
    } 
} 

#endif // _WIN32

#endif

//
// 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; 
    
  // Handle resize,
  //  e.g. smaller view windows
  //  with border and/or status bar.

  viewwindowx = (SCREENWIDTH-width) >> 1; 

  // Column offset. For windows.

  for (i=0 ; i<width ; i++) 
    columnofs[i] = viewwindowx + i;
    
  // Same with base row offset.

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

  // Preclaculate all row offsets.

  for (i=0 ; i<height ; i++) 
    ylookup[i] = screens[0] + (i+viewwindowy)*SCREENWIDTH; 
} 

//
// R_FillBackScreen
// Fills the back screen with a pattern
//  for variable screen sizes
// Also draws a beveled edge.
//

void R_FillBackScreen (void) 
{ 
  int     x,y; 

  if (scaledviewwidth == SCREENWIDTH)
    return;

  M_DrawBackground(gamemode == commercial ? "GRNROCK" : "FLOOR7_2", screens[1]);
        
  for (x=0; x<scaledviewwidth; x+=8)
    V_DrawPatchFromName(viewwindowx+x,viewwindowy-8,1,"brdr_t");

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

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

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

  // Draw beveled edge. 
  V_DrawPatchFromName(viewwindowx-8,viewwindowy-8,1,"brdr_tl");
    
  V_DrawPatchFromName(viewwindowx+scaledviewwidth,viewwindowy-8,1,"brdr_tr");
    
  V_DrawPatchFromName(viewwindowx-8,viewwindowy+viewheight,1,"brdr_bl");
    
  V_DrawPatchFromName(viewwindowx+scaledviewwidth,viewwindowy+viewheight,1,"brdr_br");
} 

//
// Copy a screen buffer.
//

void R_VideoErase(unsigned ofs, int count)
{
  // proff 11/99: not needed in OpenGL
#ifndef GL_DOOM
  memcpy(screens[0]+ofs, screens[1]+ofs, count);   // LFB copy.
#endif
}

//
// R_DrawViewBorder
// Draws the border around the view
//  for different size windows?
//
// killough 11/98: 
// Rewritten to avoid relying on screen wraparound, so that it
// can scale to hires automatically in R_VideoErase().
//

void R_DrawViewBorder(void) 
{ 
  int side, ofs, i;

  if (viewwidth == SCREENWIDTH) 
    return;

#ifdef GL_DOOM
  // proff 11/99: we don't have a backscreen in OpenGL from where we can copy this
  R_FillBackScreen();
  return;
#endif

  // copy top
  for (ofs = 0, i = viewwindowy; i--; ofs += SCREENWIDTH)
    R_VideoErase(ofs, SCREENWIDTH); 

  // copy sides
  for (side = viewwindowx, i = viewheight; i--;)
    { 
      R_VideoErase(ofs, side); 
      ofs += SCREENWIDTH;
      R_VideoErase(ofs - side, side); 
    } 

  // copy bottom 
  for (i = viewwindowy; i--; ofs += SCREENWIDTH)
    R_VideoErase(ofs, SCREENWIDTH); 
} 

//----------------------------------------------------------------------------
//
// $Log: R_draw.c,v $
// Revision 1.2  2000/04/26 20:00:03  proff_fs
// now using SDL for video and sound output.
// sound output is currently mono only.
// Get SDL from:
// http://www.devolution.com/~slouken/SDL/
//
// Revision 1.1.1.1  2000/04/09 18:01:30  proff_fs
// Initial login
//
// Revision 1.16  1998/05/03  22:41:46  killough
// beautification
//
// Revision 1.15  1998/04/19  01:16:48  killough
// Tidy up last fix's code
//
// Revision 1.14  1998/04/17  15:26:55  killough
// fix showstopper
//
// Revision 1.13  1998/04/12  01:57:51  killough
// Add main_tranmap
//
// Revision 1.12  1998/03/23  03:36:28  killough
// Use new 'fullcolormap' for fuzzy columns
//
// Revision 1.11  1998/02/23  04:54:59  killough
// #ifdef out translucency code since its in asm
//
// Revision 1.10  1998/02/20  21:57:04  phares
// Preliminarey sprite translucency
//
// Revision 1.9  1998/02/17  06:23:40  killough
// #ifdef out code duplicated in asm for djgpp targets
//
// Revision 1.8  1998/02/09  03:18:02  killough
// Change MAXWIDTH, MAXHEIGHT defintions
//
// Revision 1.7  1998/02/02  13:17:55  killough
// performance tuning
//
// Revision 1.6  1998/01/27  16:33:59  phares
// more testing
//
// Revision 1.5  1998/01/27  16:32:24  phares
// testing
//
// Revision 1.4  1998/01/27  15:56:58  phares
// Comment about invisibility
//
// Revision 1.3  1998/01/26  19:24:40  phares
// First rev with no ^Ms
//
// Revision 1.2  1998/01/26  05:05:55  killough
// Use unrolled version of R_DrawSpan
//
// Revision 1.1.1.1  1998/01/19  14:03:02  rand
// Lee's Jan 19 sources
//
//
//----------------------------------------------------------------------------