ref: a7a315bff61bff58a9c918294f53c1e87d7ae7bb
dir: /sys/src/games/doom/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 "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--);
}
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 *)(((uintptr)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--);
}
//
// 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);
}