kolibrios-fun/programs/games/doom/trunk/r_draw.c

// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// 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 1.4 1997/02/03 16:47:55 b1 Exp $";

#include "doomtype.h"
#include "doomdef.h"

#include "i_system.h"
#include "z_zone.h"
#include "w_wad.h"

#include "r_local.h"

// Needs access to LFB (guess what).
#include "v_video.h"

// State.
#include "doomstat.h"


// ?
#define MAXWIDTH                        1120
#define MAXHEIGHT                       832

// status bar height at bottom of screen
#define SBARHEIGHT              32

//
// 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];   
 
 


//
// 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;

// first pixel in a column (possibly virtual) 
byte*                   dc_source;              

// just for profiling 
int                     dccount;

//
// 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; 
    byte*               dest; 
    fixed_t             frac;
    fixed_t             fracstep;        
 
    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: %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.
    do 
    {
        // Re-map color indices from wall texture column
        //  using a lighting/special effects LUT.
        *dest = dc_colormap[dc_source[(frac>>FRACBITS)&127]];
        
        dest += SCREENWIDTH; 
        frac += fracstep;
        
    } while (count--); 
} 



// UNUSED.
// Loop unrolled.
#if 0
void R_DrawColumn (void) 
{ 
    int                 count; 
    byte*               source;
    byte*               dest;
    byte*               colormap;
    
    unsigned            frac;
    unsigned            fracstep;
    unsigned            fracstep2;
    unsigned            fracstep3;
    unsigned            fracstep4;       
 
    count = dc_yh - dc_yl + 1; 

    source = dc_source;
    colormap = dc_colormap;              
    dest = ylookup[dc_yl] + columnofs[dc_x];  
         
    fracstep = dc_iscale<<9; 
    frac = (dc_texturemid + (dc_yl-centery)*dc_iscale)<<9; 
 
    fracstep2 = fracstep+fracstep;
    fracstep3 = fracstep2+fracstep;
    fracstep4 = fracstep3+fracstep;
        
    while (count >= 8) 
    { 
        dest[0] = colormap[source[frac>>25]]; 
        dest[SCREENWIDTH] = colormap[source[(frac+fracstep)>>25]]; 
        dest[SCREENWIDTH*2] = colormap[source[(frac+fracstep2)>>25]]; 
        dest[SCREENWIDTH*3] = colormap[source[(frac+fracstep3)>>25]];
        
        frac += fracstep4; 

        dest[SCREENWIDTH*4] = colormap[source[frac>>25]]; 
        dest[SCREENWIDTH*5] = colormap[source[(frac+fracstep)>>25]]; 
        dest[SCREENWIDTH*6] = colormap[source[(frac+fracstep2)>>25]]; 
        dest[SCREENWIDTH*7] = colormap[source[(frac+fracstep3)>>25]]; 

        frac += fracstep4; 
        dest += SCREENWIDTH*8; 
        count -= 8;
    } 
        
    while (count > 0)
    { 
        *dest = colormap[source[frac>>25]]; 
        dest += SCREENWIDTH; 
        frac += fracstep; 
        count--;
    } 
}
#endif


void R_DrawColumnLow (void) 
{ 
    int                 count; 
    byte*               dest; 
    byte*               dest2;
    fixed_t             frac;
    fixed_t             fracstep;        
 
    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_DrawColumn: %i to %i at %i", dc_yl, dc_yh, dc_x);
    }
    //  dccount++; 
#endif 
    // Blocky mode, need to multiply by 2.
    dc_x <<= 1;
    
    dest = ylookup[dc_yl] + columnofs[dc_x];
    dest2 = ylookup[dc_yl] + columnofs[dc_x+1];
    
    fracstep = dc_iscale; 
    frac = dc_texturemid + (dc_yl-centery)*fracstep;
    
    do 
    {
        // Hack. Does not work corretly.
        *dest2 = *dest = dc_colormap[dc_source[(frac>>FRACBITS)&127]];
        dest += SCREENWIDTH;
        dest2 += SCREENWIDTH;
        frac += fracstep; 

    } while (count--);
}


//
// Spectre/Invisibility.
//
#define FUZZTABLE               50 
#define FUZZOFF (SCREENWIDTH)


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 
}; 

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.
    /* WATCOM code 
    if (detailshift)
    {
        if (dc_x & 1)
        {
            outpw (GC_INDEX,GC_READMAP+(2<<8) ); 
            outp (SC_INDEX+1,12); 
        }
        else
        {
            outpw (GC_INDEX,GC_READMAP); 
            outp (SC_INDEX+1,3); 
        }
        dest = destview + dc_yl*80 + (dc_x>>1); 
    }
    else
    {
        outpw (GC_INDEX,GC_READMAP+((dc_x&3)<<8) ); 
        outp (SC_INDEX+1,1<<(dc_x&3)); 
        dest = destview + dc_yl*80 + (dc_x>>2); 
    }*/

    
    // 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.
        *dest = colormaps[6*256+dest[fuzzoffset[fuzzpos]]]; 

        // 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;
byte*   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 


    // WATCOM VGA specific.
    /* Keep for fixing.
    if (detailshift)
    {
        if (dc_x & 1)
            outp (SC_INDEX+1,12); 
        else
            outp (SC_INDEX+1,3);
        
        dest = destview + dc_yl*80 + (dc_x>>1); 
    }
    else
    {
        outp (SC_INDEX+1,1<<(dc_x&3)); 

        dest = destview + dc_yl*80 + (dc_x>>2); 
    }*/

    
    // 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;
        
    translationtables = Z_Malloc (256*3+255, PU_STATIC, 0);
    translationtables = (byte *)(( (int)translationtables + 255 )& ~255);
    
    // 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;      

// just for profiling
int                     dscount;


//
// Draws the actual span.
void R_DrawSpan (void) 
{ 
    fixed_t             xfrac;
    fixed_t             yfrac; 
    byte*               dest; 
    int                 count;
    int                 spot; 
         
#ifdef RANGECHECK 
    if (ds_x2 < ds_x1
        || ds_x1<0
        || ds_x2>=SCREENWIDTH  
        || (unsigned)ds_y>SCREENHEIGHT)
    {
        I_Error( "R_DrawSpan: %i to %i at %i",
                 ds_x1,ds_x2,ds_y);
    }
//      dscount++; 
#endif 

    
    xfrac = ds_xfrac; 
    yfrac = ds_yfrac; 
         
    dest = ylookup[ds_y] + columnofs[ds_x1];

    // We do not check for zero spans here?
    count = ds_x2 - ds_x1; 

    do 
    {
        // Current texture index in u,v.
        spot = ((yfrac>>(16-6))&(63*64)) + ((xfrac>>16)&63);

        // Lookup pixel from flat texture tile,
        //  re-index using light/colormap.
        *dest++ = ds_colormap[ds_source[spot]];

        // Next step in u,v.
        xfrac += ds_xstep; 
        yfrac += ds_ystep;
        
    } while (count--); 
} 



// UNUSED.
// Loop unrolled by 4.
#if 0
void R_DrawSpan (void) 
{ 
    unsigned    position, step;

    byte*       source;
    byte*       colormap;
    byte*       dest;
    
    unsigned    count;
    usingned    spot; 
    unsigned    value;
    unsigned    temp;
    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]]; 
                
        count -= 4;
        dest += 4;
    } 
    while (count > 0) 
    { 
        ytemp = position>>4;
        ytemp = ytemp & 4032;
        xtemp = position>>26;
        spot = xtemp | ytemp;
        position += step;
        *dest++ = colormap[source[spot]]; 
        count--;
    } 
} 
#endif


//
// Again..
//
void R_DrawSpanLow (void) 
{ 
    fixed_t             xfrac;
    fixed_t             yfrac; 
    byte*               dest; 
    int                 count;
    int                 spot; 
         
#ifdef RANGECHECK 
    if (ds_x2 < ds_x1
        || ds_x1<0
        || ds_x2>=SCREENWIDTH  
        || (unsigned)ds_y>SCREENHEIGHT)
    {
        I_Error( "R_DrawSpan: %i to %i at %i",
                 ds_x1,ds_x2,ds_y);
    }
//      dscount++; 
#endif 
         
    xfrac = ds_xfrac; 
    yfrac = ds_yfrac; 

    // Blocky mode, need to multiply by 2.
    ds_x1 <<= 1;
    ds_x2 <<= 1;
    
    dest = ylookup[ds_y] + columnofs[ds_x1];
  
    
    count = ds_x2 - ds_x1; 
    do 
    { 
        spot = ((yfrac>>(16-6))&(63*64)) + ((xfrac>>16)&63);
        // Lowres/blocky mode does it twice,
        //  while scale is adjusted appropriately.
        *dest++ = ds_colormap[ds_source[spot]]; 
        *dest++ = ds_colormap[ds_source[spot]];
        
        xfrac += ds_xstep; 
        yfrac += ds_ystep; 

    } while (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; 

    // 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;

    // Samw with base row offset.
    if (width == SCREENWIDTH) 
        viewwindowy = 0; 
    else 
        viewwindowy = (SCREENHEIGHT-SBARHEIGHT-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) 
{ 
    byte*       src;
    byte*       dest; 
    int         x;
    int         y; 
    patch_t*    patch;

    // DOOM border patch.
    char        name1[] = "FLOOR7_2";

    // DOOM II border patch.
    char        name2[] = "GRNROCK";    

    char*       name;
        
    if (scaledviewwidth == 320)
        return;
        
    if ( gamemode == commercial)
        name = name2;
    else
        name = name1;
    
    src = W_CacheLumpName (name, PU_CACHE); 
    dest = screens[1]; 
         
    for (y=0 ; y<SCREENHEIGHT-SBARHEIGHT ; y++) 
    { 
        for (x=0 ; x<SCREENWIDTH/64 ; x++) 
        { 
            memcpy (dest, src+((y&63)<<6), 64); 
            dest += 64; 
        } 

        if (SCREENWIDTH&63) 
        { 
            memcpy (dest, src+((y&63)<<6), SCREENWIDTH&63); 
            dest += (SCREENWIDTH&63); 
        } 
    } 
        
    patch = W_CacheLumpName ("brdr_t",PU_CACHE);

    for (x=0 ; x<scaledviewwidth ; x+=8)
        V_DrawPatch (viewwindowx+x,viewwindowy-8,1,patch);
    patch = W_CacheLumpName ("brdr_b",PU_CACHE);

    for (x=0 ; x<scaledviewwidth ; x+=8)
        V_DrawPatch (viewwindowx+x,viewwindowy+viewheight,1,patch);
    patch = W_CacheLumpName ("brdr_l",PU_CACHE);

    for (y=0 ; y<viewheight ; y+=8)
        V_DrawPatch (viewwindowx-8,viewwindowy+y,1,patch);
    patch = W_CacheLumpName ("brdr_r",PU_CACHE);

    for (y=0 ; y<viewheight ; y+=8)
        V_DrawPatch (viewwindowx+scaledviewwidth,viewwindowy+y,1,patch);


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

//
// Copy a screen buffer.
//
void
R_VideoErase
( unsigned      ofs,
  int           count ) 
{ 
  // LFB copy.
  // This might not be a good idea if memcpy
  //  is not optiomal, e.g. byte by byte on
  //  a 32bit CPU, as GNU GCC/Linux libc did
  //  at one point.
    memcpy (screens[0]+ofs, screens[1]+ofs, count); 
} 


//
// R_DrawViewBorder
// Draws the border around the view
//  for different size windows?
//
void
V_MarkRect
( int           x,
  int           y,
  int           width,
  int           height ); 
 
void R_DrawViewBorder (void) 
{ 
    int         top;
    int         side;
    int         ofs;
    int         i; 
 
    if (scaledviewwidth == SCREENWIDTH) 
        return; 
  
    top = ((SCREENHEIGHT-SBARHEIGHT)-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; 
    } 

    // ? 
    V_MarkRect (0,0,SCREENWIDTH, SCREENHEIGHT-SBARHEIGHT); 
}