ref: cc89ba80b3f821fdff89ff66f3541a17959e7ea2
dir: /ref/r_poly.c/
/*
Copyright (C) 1997-2001 Id Software, Inc.
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.
*/
#include <u.h>
#include <libc.h>
#include <stdio.h>
#include "../dat.h"
#include "../fns.h"
#define AFFINE_SPANLET_SIZE 16
#define AFFINE_SPANLET_SIZE_BITS 4
typedef struct
{
byte *pbase, *pdest;
short *pz;
fixed16_t s, t;
fixed16_t sstep, tstep;
int izi, izistep, izistep_times_2;
int spancount;
unsigned u, v;
} spanletvars_t;
spanletvars_t s_spanletvars;
static int r_polyblendcolor;
static espan_t *s_polygon_spans;
polydesc_t r_polydesc;
msurface_t *r_alpha_surfaces;
extern int *r_turb_turb;
static int clip_current;
vec5_t r_clip_verts[2][MAXWORKINGVERTS+2];
static int s_minindex, s_maxindex;
static void R_DrawPoly( qboolean iswater );
/*
** R_DrawSpanletOpaque
*/
void R_DrawSpanletOpaque( void )
{
unsigned btemp;
do
{
unsigned ts, tt;
ts = s_spanletvars.s >> 16;
tt = s_spanletvars.t >> 16;
btemp = *(s_spanletvars.pbase + (ts) + (tt) * cachewidth);
if (btemp != 255)
{
if (*s_spanletvars.pz <= (s_spanletvars.izi >> 16))
{
*s_spanletvars.pz = s_spanletvars.izi >> 16;
*s_spanletvars.pdest = btemp;
}
}
s_spanletvars.izi += s_spanletvars.izistep;
s_spanletvars.pdest++;
s_spanletvars.pz++;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
} while (--s_spanletvars.spancount > 0);
}
/*
** R_DrawSpanletTurbulentStipple33
*/
void R_DrawSpanletTurbulentStipple33( void )
{
unsigned btemp;
int sturb, tturb;
byte *pdest = s_spanletvars.pdest;
short *pz = s_spanletvars.pz;
int izi = s_spanletvars.izi;
if ( s_spanletvars.v & 1 )
{
s_spanletvars.pdest += s_spanletvars.spancount;
s_spanletvars.pz += s_spanletvars.spancount;
if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
else
s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
if ( s_spanletvars.u & 1 )
{
izi += s_spanletvars.izistep;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest++;
pz++;
s_spanletvars.spancount--;
}
s_spanletvars.sstep *= 2;
s_spanletvars.tstep *= 2;
while ( s_spanletvars.spancount > 0 )
{
sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;
btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );
if ( *pz <= ( izi >> 16 ) )
*pdest = btemp;
izi += s_spanletvars.izistep_times_2;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest += 2;
pz += 2;
s_spanletvars.spancount -= 2;
}
}
}
/*
** R_DrawSpanletTurbulentStipple66
*/
void R_DrawSpanletTurbulentStipple66( void )
{
unsigned btemp;
int sturb, tturb;
byte *pdest = s_spanletvars.pdest;
short *pz = s_spanletvars.pz;
int izi = s_spanletvars.izi;
if ( !( s_spanletvars.v & 1 ) )
{
s_spanletvars.pdest += s_spanletvars.spancount;
s_spanletvars.pz += s_spanletvars.spancount;
if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
else
s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
if ( s_spanletvars.u & 1 )
{
izi += s_spanletvars.izistep;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest++;
pz++;
s_spanletvars.spancount--;
}
s_spanletvars.sstep *= 2;
s_spanletvars.tstep *= 2;
while ( s_spanletvars.spancount > 0 )
{
sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;
btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );
if ( *pz <= ( izi >> 16 ) )
*pdest = btemp;
izi += s_spanletvars.izistep_times_2;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest += 2;
pz += 2;
s_spanletvars.spancount -= 2;
}
}
else
{
s_spanletvars.pdest += s_spanletvars.spancount;
s_spanletvars.pz += s_spanletvars.spancount;
if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
else
s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
while ( s_spanletvars.spancount > 0 )
{
sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;
btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );
if ( *pz <= ( izi >> 16 ) )
*pdest = btemp;
izi += s_spanletvars.izistep;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest++;
pz++;
s_spanletvars.spancount--;
}
}
}
/*
** R_DrawSpanletTurbulentBlended
*/
void R_DrawSpanletTurbulentBlended66( void )
{
unsigned btemp;
int sturb, tturb;
do
{
sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;
btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );
if ( *s_spanletvars.pz <= ( s_spanletvars.izi >> 16 ) )
*s_spanletvars.pdest = vid.alphamap[btemp*256+*s_spanletvars.pdest];
s_spanletvars.izi += s_spanletvars.izistep;
s_spanletvars.pdest++;
s_spanletvars.pz++;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
} while ( --s_spanletvars.spancount > 0 );
}
void R_DrawSpanletTurbulentBlended33( void )
{
unsigned btemp;
int sturb, tturb;
do
{
sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;
btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );
if ( *s_spanletvars.pz <= ( s_spanletvars.izi >> 16 ) )
*s_spanletvars.pdest = vid.alphamap[btemp+*s_spanletvars.pdest*256];
s_spanletvars.izi += s_spanletvars.izistep;
s_spanletvars.pdest++;
s_spanletvars.pz++;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
} while ( --s_spanletvars.spancount > 0 );
}
/*
** R_DrawSpanlet33
*/
void R_DrawSpanlet33( void )
{
unsigned btemp;
do
{
unsigned ts, tt;
ts = s_spanletvars.s >> 16;
tt = s_spanletvars.t >> 16;
btemp = *(s_spanletvars.pbase + (ts) + (tt) * cachewidth);
if ( btemp != 255 )
{
if (*s_spanletvars.pz <= (s_spanletvars.izi >> 16))
{
*s_spanletvars.pdest = vid.alphamap[btemp+*s_spanletvars.pdest*256];
}
}
s_spanletvars.izi += s_spanletvars.izistep;
s_spanletvars.pdest++;
s_spanletvars.pz++;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
} while (--s_spanletvars.spancount > 0);
}
void R_DrawSpanletConstant33( void )
{
do
{
if (*s_spanletvars.pz <= (s_spanletvars.izi >> 16))
{
*s_spanletvars.pdest = vid.alphamap[r_polyblendcolor+*s_spanletvars.pdest*256];
}
s_spanletvars.izi += s_spanletvars.izistep;
s_spanletvars.pdest++;
s_spanletvars.pz++;
} while (--s_spanletvars.spancount > 0);
}
/*
** R_DrawSpanlet66
*/
void R_DrawSpanlet66( void )
{
unsigned btemp;
do
{
unsigned ts, tt;
ts = s_spanletvars.s >> 16;
tt = s_spanletvars.t >> 16;
btemp = *(s_spanletvars.pbase + (ts) + (tt) * cachewidth);
if ( btemp != 255 )
{
if (*s_spanletvars.pz <= (s_spanletvars.izi >> 16))
{
*s_spanletvars.pdest = vid.alphamap[btemp*256+*s_spanletvars.pdest];
}
}
s_spanletvars.izi += s_spanletvars.izistep;
s_spanletvars.pdest++;
s_spanletvars.pz++;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
} while (--s_spanletvars.spancount > 0);
}
/*
** R_DrawSpanlet33Stipple
*/
void R_DrawSpanlet33Stipple( void )
{
unsigned btemp;
byte *pdest = s_spanletvars.pdest;
short *pz = s_spanletvars.pz;
int izi = s_spanletvars.izi;
if ( r_polydesc.stipple_parity ^ ( s_spanletvars.v & 1 ) )
{
s_spanletvars.pdest += s_spanletvars.spancount;
s_spanletvars.pz += s_spanletvars.spancount;
if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
else
s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
if ( r_polydesc.stipple_parity ^ ( s_spanletvars.u & 1 ) )
{
izi += s_spanletvars.izistep;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest++;
pz++;
s_spanletvars.spancount--;
}
s_spanletvars.sstep *= 2;
s_spanletvars.tstep *= 2;
while ( s_spanletvars.spancount > 0 )
{
unsigned s = s_spanletvars.s >> 16;
unsigned t = s_spanletvars.t >> 16;
btemp = *( s_spanletvars.pbase + ( s ) + ( t * cachewidth ) );
if ( btemp != 255 )
{
if ( *pz <= ( izi >> 16 ) )
*pdest = btemp;
}
izi += s_spanletvars.izistep_times_2;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest += 2;
pz += 2;
s_spanletvars.spancount -= 2;
}
}
}
/*
** R_DrawSpanlet66Stipple
*/
void R_DrawSpanlet66Stipple( void )
{
unsigned btemp;
byte *pdest = s_spanletvars.pdest;
short *pz = s_spanletvars.pz;
int izi = s_spanletvars.izi;
s_spanletvars.pdest += s_spanletvars.spancount;
s_spanletvars.pz += s_spanletvars.spancount;
if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
else
s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
if ( r_polydesc.stipple_parity ^ ( s_spanletvars.v & 1 ) )
{
if ( r_polydesc.stipple_parity ^ ( s_spanletvars.u & 1 ) )
{
izi += s_spanletvars.izistep;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest++;
pz++;
s_spanletvars.spancount--;
}
s_spanletvars.sstep *= 2;
s_spanletvars.tstep *= 2;
while ( s_spanletvars.spancount > 0 )
{
unsigned s = s_spanletvars.s >> 16;
unsigned t = s_spanletvars.t >> 16;
btemp = *( s_spanletvars.pbase + ( s ) + ( t * cachewidth ) );
if ( btemp != 255 )
{
if ( *pz <= ( izi >> 16 ) )
*pdest = btemp;
}
izi += s_spanletvars.izistep_times_2;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest += 2;
pz += 2;
s_spanletvars.spancount -= 2;
}
}
else
{
while ( s_spanletvars.spancount > 0 )
{
unsigned s = s_spanletvars.s >> 16;
unsigned t = s_spanletvars.t >> 16;
btemp = *( s_spanletvars.pbase + ( s ) + ( t * cachewidth ) );
if ( btemp != 255 )
{
if ( *pz <= ( izi >> 16 ) )
*pdest = btemp;
}
izi += s_spanletvars.izistep;
s_spanletvars.s += s_spanletvars.sstep;
s_spanletvars.t += s_spanletvars.tstep;
pdest++;
pz++;
s_spanletvars.spancount--;
}
}
}
/*
** R_ClipPolyFace
**
** Clips the winding at clip_verts[clip_current] and changes clip_current
** Throws out the back side
*/
int R_ClipPolyFace (int nump, clipplane_t *pclipplane)
{
int i, outcount;
float dists[MAXWORKINGVERTS+3];
float frac, clipdist, *pclipnormal;
float *in, *instep, *outstep, *vert2;
clipdist = pclipplane->dist;
pclipnormal = pclipplane->normal;
// calc dists
if (clip_current)
{
in = r_clip_verts[1][0];
outstep = r_clip_verts[0][0];
clip_current = 0;
}
else
{
in = r_clip_verts[0][0];
outstep = r_clip_verts[1][0];
clip_current = 1;
}
instep = in;
for (i=0 ; i<nump ; i++, instep += sizeof (vec5_t) / sizeof (float))
{
dists[i] = DotProduct (instep, pclipnormal) - clipdist;
}
// handle wraparound case
dists[nump] = dists[0];
memcpy (instep, in, sizeof (vec5_t));
// clip the winding
instep = in;
outcount = 0;
for (i=0 ; i<nump ; i++, instep += sizeof (vec5_t) / sizeof (float))
{
if (dists[i] >= 0)
{
memcpy (outstep, instep, sizeof (vec5_t));
outstep += sizeof (vec5_t) / sizeof (float);
outcount++;
}
if (dists[i] == 0 || dists[i+1] == 0)
continue;
if ( (dists[i] > 0) == (dists[i+1] > 0) )
continue;
// split it into a new vertex
frac = dists[i] / (dists[i] - dists[i+1]);
vert2 = instep + sizeof (vec5_t) / sizeof (float);
outstep[0] = instep[0] + frac*(vert2[0] - instep[0]);
outstep[1] = instep[1] + frac*(vert2[1] - instep[1]);
outstep[2] = instep[2] + frac*(vert2[2] - instep[2]);
outstep[3] = instep[3] + frac*(vert2[3] - instep[3]);
outstep[4] = instep[4] + frac*(vert2[4] - instep[4]);
outstep += sizeof (vec5_t) / sizeof (float);
outcount++;
}
return outcount;
}
/*
** R_PolygonDrawSpans
*/
void R_PolygonDrawSpans(espan_t *pspan, qboolean iswater )
{
int count;
fixed16_t snext, tnext;
float sdivz, tdivz, zi, z, du, dv, spancountminus1;
float sdivzspanletstepu, tdivzspanletstepu, zispanletstepu;
s_spanletvars.pbase = cacheblock;
if ( iswater )
r_turb_turb = sintable + ((int)(r_newrefdef.time*SPEED)&(CYCLE-1));
sdivzspanletstepu = d_sdivzstepu * AFFINE_SPANLET_SIZE;
tdivzspanletstepu = d_tdivzstepu * AFFINE_SPANLET_SIZE;
zispanletstepu = d_zistepu * AFFINE_SPANLET_SIZE;
// we count on FP exceptions being turned off to avoid range problems
s_spanletvars.izistep = (int)(d_zistepu * 0x8000 * 0x10000);
s_spanletvars.izistep_times_2 = s_spanletvars.izistep * 2;
s_spanletvars.pz = 0;
do
{
s_spanletvars.pdest = (byte *)d_viewbuffer + ( d_scantable[pspan->v] /*r_screenwidth * pspan->v*/) + pspan->u;
s_spanletvars.pz = d_pzbuffer + (d_zwidth * pspan->v) + pspan->u;
s_spanletvars.u = pspan->u;
s_spanletvars.v = pspan->v;
count = pspan->count;
if (count <= 0)
goto NextSpan;
// calculate the initial s/z, t/z, 1/z, s, and t and clamp
du = (float)pspan->u;
dv = (float)pspan->v;
sdivz = d_sdivzorigin + dv*d_sdivzstepv + du*d_sdivzstepu;
tdivz = d_tdivzorigin + dv*d_tdivzstepv + du*d_tdivzstepu;
zi = d_ziorigin + dv*d_zistepv + du*d_zistepu;
z = (float)0x10000 / zi; // prescale to 16.16 fixed-point
// we count on FP exceptions being turned off to avoid range problems
s_spanletvars.izi = (int)(zi * 0x8000 * 0x10000);
s_spanletvars.s = (int)(sdivz * z) + sadjust;
s_spanletvars.t = (int)(tdivz * z) + tadjust;
if ( !iswater )
{
if (s_spanletvars.s > bbextents)
s_spanletvars.s = bbextents;
else if (s_spanletvars.s < 0)
s_spanletvars.s = 0;
if (s_spanletvars.t > bbextentt)
s_spanletvars.t = bbextentt;
else if (s_spanletvars.t < 0)
s_spanletvars.t = 0;
}
do
{
// calculate s and t at the far end of the span
if (count >= AFFINE_SPANLET_SIZE )
s_spanletvars.spancount = AFFINE_SPANLET_SIZE;
else
s_spanletvars.spancount = count;
count -= s_spanletvars.spancount;
if (count)
{
// calculate s/z, t/z, zi->fixed s and t at far end of span,
// calculate s and t steps across span by shifting
sdivz += sdivzspanletstepu;
tdivz += tdivzspanletstepu;
zi += zispanletstepu;
z = (float)0x10000 / zi; // prescale to 16.16 fixed-point
snext = (int)(sdivz * z) + sadjust;
tnext = (int)(tdivz * z) + tadjust;
if ( !iswater )
{
if (snext > bbextents)
snext = bbextents;
else if (snext < AFFINE_SPANLET_SIZE)
snext = AFFINE_SPANLET_SIZE; // prevent round-off error on <0 steps from
// from causing overstepping & running off the
// edge of the texture
if (tnext > bbextentt)
tnext = bbextentt;
else if (tnext < AFFINE_SPANLET_SIZE)
tnext = AFFINE_SPANLET_SIZE; // guard against round-off error on <0 steps
}
s_spanletvars.sstep = (snext - s_spanletvars.s) >> AFFINE_SPANLET_SIZE_BITS;
s_spanletvars.tstep = (tnext - s_spanletvars.t) >> AFFINE_SPANLET_SIZE_BITS;
}
else
{
// calculate s/z, t/z, zi->fixed s and t at last pixel in span (so
// can't step off polygon), clamp, calculate s and t steps across
// span by division, biasing steps low so we don't run off the
// texture
spancountminus1 = (float)(s_spanletvars.spancount - 1);
sdivz += d_sdivzstepu * spancountminus1;
tdivz += d_tdivzstepu * spancountminus1;
zi += d_zistepu * spancountminus1;
z = (float)0x10000 / zi; // prescale to 16.16 fixed-point
snext = (int)(sdivz * z) + sadjust;
tnext = (int)(tdivz * z) + tadjust;
if ( !iswater )
{
if (snext > bbextents)
snext = bbextents;
else if (snext < AFFINE_SPANLET_SIZE)
snext = AFFINE_SPANLET_SIZE; // prevent round-off error on <0 steps from
// from causing overstepping & running off the
// edge of the texture
if (tnext > bbextentt)
tnext = bbextentt;
else if (tnext < AFFINE_SPANLET_SIZE)
tnext = AFFINE_SPANLET_SIZE; // guard against round-off error on <0 steps
}
if (s_spanletvars.spancount > 1)
{
s_spanletvars.sstep = (snext - s_spanletvars.s) / (s_spanletvars.spancount - 1);
s_spanletvars.tstep = (tnext - s_spanletvars.t) / (s_spanletvars.spancount - 1);
}
}
if ( iswater )
{
s_spanletvars.s = s_spanletvars.s & ((CYCLE<<16)-1);
s_spanletvars.t = s_spanletvars.t & ((CYCLE<<16)-1);
}
r_polydesc.drawspanlet();
s_spanletvars.s = snext;
s_spanletvars.t = tnext;
} while (count > 0);
NextSpan:
pspan++;
} while (pspan->count != DS_SPAN_LIST_END);
}
/*
**
** R_PolygonScanLeftEdge
**
** Goes through the polygon and scans the left edge, filling in
** screen coordinate data for the spans
*/
void R_PolygonScanLeftEdge (void)
{
int i, v, itop, ibottom, lmaxindex;
emitpoint_t *pvert, *pnext;
espan_t *pspan;
float du, dv, vtop, vbottom, slope;
fixed16_t u, u_step;
pspan = s_polygon_spans;
i = s_minindex;
if (i == 0)
i = r_polydesc.nump;
lmaxindex = s_maxindex;
if (lmaxindex == 0)
lmaxindex = r_polydesc.nump;
vtop = ceil (r_polydesc.pverts[i].v);
do
{
pvert = &r_polydesc.pverts[i];
pnext = pvert - 1;
vbottom = ceil (pnext->v);
if (vtop < vbottom)
{
du = pnext->u - pvert->u;
dv = pnext->v - pvert->v;
slope = du / dv;
u_step = (int)(slope * 0x10000);
// adjust u to ceil the integer portion
u = (int)((pvert->u + (slope * (vtop - pvert->v))) * 0x10000) +
(0x10000 - 1);
itop = (int)vtop;
ibottom = (int)vbottom;
for (v=itop ; v<ibottom ; v++)
{
pspan->u = u >> 16;
pspan->v = v;
u += u_step;
pspan++;
}
}
vtop = vbottom;
i--;
if (i == 0)
i = r_polydesc.nump;
} while (i != lmaxindex);
}
/*
** R_PolygonScanRightEdge
**
** Goes through the polygon and scans the right edge, filling in
** count values.
*/
void R_PolygonScanRightEdge (void)
{
int i, v, itop, ibottom;
emitpoint_t *pvert, *pnext;
espan_t *pspan;
float du, dv, vtop, vbottom, slope, uvert, unext, vvert, vnext;
fixed16_t u, u_step;
pspan = s_polygon_spans;
i = s_minindex;
vvert = r_polydesc.pverts[i].v;
if (vvert < r_refdef.fvrecty_adj)
vvert = r_refdef.fvrecty_adj;
if (vvert > r_refdef.fvrectbottom_adj)
vvert = r_refdef.fvrectbottom_adj;
vtop = ceil (vvert);
do
{
pvert = &r_polydesc.pverts[i];
pnext = pvert + 1;
vnext = pnext->v;
if (vnext < r_refdef.fvrecty_adj)
vnext = r_refdef.fvrecty_adj;
if (vnext > r_refdef.fvrectbottom_adj)
vnext = r_refdef.fvrectbottom_adj;
vbottom = ceil (vnext);
if (vtop < vbottom)
{
uvert = pvert->u;
if (uvert < r_refdef.fvrectx_adj)
uvert = r_refdef.fvrectx_adj;
if (uvert > r_refdef.fvrectright_adj)
uvert = r_refdef.fvrectright_adj;
unext = pnext->u;
if (unext < r_refdef.fvrectx_adj)
unext = r_refdef.fvrectx_adj;
if (unext > r_refdef.fvrectright_adj)
unext = r_refdef.fvrectright_adj;
du = unext - uvert;
dv = vnext - vvert;
slope = du / dv;
u_step = (int)(slope * 0x10000);
// adjust u to ceil the integer portion
u = (int)((uvert + (slope * (vtop - vvert))) * 0x10000) +
(0x10000 - 1);
itop = (int)vtop;
ibottom = (int)vbottom;
for (v=itop ; v<ibottom ; v++)
{
pspan->count = (u >> 16) - pspan->u;
u += u_step;
pspan++;
}
}
vtop = vbottom;
vvert = vnext;
i++;
if (i == r_polydesc.nump)
i = 0;
} while (i != s_maxindex);
pspan->count = DS_SPAN_LIST_END; // mark the end of the span list
}
/*
** R_ClipAndDrawPoly
*/
void R_ClipAndDrawPoly( float alpha, qboolean isturbulent, qboolean textured )
{
emitpoint_t outverts[MAXWORKINGVERTS+3], *pout;
float *pv;
int i, nump;
float scale;
vec3_t transformed, local;
if ( !textured )
{
r_polydesc.drawspanlet = R_DrawSpanletConstant33;
}
else
{
/*
** choose the correct spanlet routine based on alpha
*/
if ( alpha == 1 )
{
// isturbulent is ignored because we know that turbulent surfaces
// can't be opaque
r_polydesc.drawspanlet = R_DrawSpanletOpaque;
}
else
{
if ( sw_stipplealpha->value )
{
if ( isturbulent )
{
if ( alpha > 0.33 )
r_polydesc.drawspanlet = R_DrawSpanletTurbulentStipple66;
else
r_polydesc.drawspanlet = R_DrawSpanletTurbulentStipple33;
}
else
{
if ( alpha > 0.33 )
r_polydesc.drawspanlet = R_DrawSpanlet66Stipple;
else
r_polydesc.drawspanlet = R_DrawSpanlet33Stipple;
}
}
else
{
if ( isturbulent )
{
if ( alpha > 0.33 )
r_polydesc.drawspanlet = R_DrawSpanletTurbulentBlended66;
else
r_polydesc.drawspanlet = R_DrawSpanletTurbulentBlended33;
}
else
{
if ( alpha > 0.33 )
r_polydesc.drawspanlet = R_DrawSpanlet66;
else
r_polydesc.drawspanlet = R_DrawSpanlet33;
}
}
}
}
// clip to the frustum in worldspace
nump = r_polydesc.nump;
clip_current = 0;
for (i=0 ; i<4 ; i++)
{
nump = R_ClipPolyFace (nump, &view_clipplanes[i]);
if (nump < 3)
return;
if (nump > MAXWORKINGVERTS)
ri.Sys_Error(ERR_DROP, "R_ClipAndDrawPoly: too many points: %d", nump );
}
// transform vertices into viewspace and project
pv = &r_clip_verts[clip_current][0][0];
for (i=0 ; i<nump ; i++)
{
VectorSubtract (pv, r_origin, local);
TransformVector (local, transformed);
if (transformed[2] < NEAR_CLIP)
transformed[2] = NEAR_CLIP;
pout = &outverts[i];
pout->zi = 1.0 / transformed[2];
pout->s = pv[3];
pout->t = pv[4];
scale = xscale * pout->zi;
pout->u = (xcenter + scale * transformed[0]);
scale = yscale * pout->zi;
pout->v = (ycenter - scale * transformed[1]);
pv += sizeof (vec5_t) / sizeof (*pv);
}
// draw it
r_polydesc.nump = nump;
r_polydesc.pverts = outverts;
R_DrawPoly( isturbulent );
}
/*
** R_BuildPolygonFromSurface
*/
void R_BuildPolygonFromSurface(msurface_t *fa)
{
int i, lindex, lnumverts;
medge_t *pedges, *r_pedge;
float *vec;
vec5_t *pverts;
float tmins[2] = { 0, 0 };
r_polydesc.nump = 0;
// reconstruct the polygon
pedges = currentmodel->edges;
lnumverts = fa->numedges;
pverts = r_clip_verts[0];
for (i=0 ; i<lnumverts ; i++)
{
lindex = currentmodel->surfedges[fa->firstedge + i];
if (lindex > 0)
{
r_pedge = &pedges[lindex];
vec = currentmodel->vertexes[r_pedge->v[0]].position;
}
else
{
r_pedge = &pedges[-lindex];
vec = currentmodel->vertexes[r_pedge->v[1]].position;
}
VectorCopy (vec, pverts[i] );
}
VectorCopy( fa->texinfo->vecs[0], r_polydesc.vright );
VectorCopy( fa->texinfo->vecs[1], r_polydesc.vup );
VectorCopy( fa->plane->normal, r_polydesc.vpn );
VectorCopy( r_origin, r_polydesc.viewer_position );
if ( fa->flags & SURF_PLANEBACK )
{
VectorSubtract( vec3_origin, r_polydesc.vpn, r_polydesc.vpn );
}
if ( fa->texinfo->flags & SURF_WARP )
{
r_polydesc.pixels = fa->texinfo->image->pixels[0];
r_polydesc.pixel_width = fa->texinfo->image->width;
r_polydesc.pixel_height = fa->texinfo->image->height;
}
else
{
surfcache_t *scache;
scache = D_CacheSurface( fa, 0 );
r_polydesc.pixels = scache->data;
r_polydesc.pixel_width = scache->width;
r_polydesc.pixel_height = scache->height;
tmins[0] = fa->texturemins[0];
tmins[1] = fa->texturemins[1];
}
r_polydesc.dist = DotProduct( r_polydesc.vpn, pverts[0] );
r_polydesc.s_offset = fa->texinfo->vecs[0][3] - tmins[0];
r_polydesc.t_offset = fa->texinfo->vecs[1][3] - tmins[1];
// scrolling texture addition
if (fa->texinfo->flags & SURF_FLOWING)
{
r_polydesc.s_offset += -128 * ( (r_newrefdef.time*0.25) - (int)(r_newrefdef.time*0.25) );
}
r_polydesc.nump = lnumverts;
}
/*
** R_PolygonCalculateGradients
*/
void R_PolygonCalculateGradients (void)
{
vec3_t p_normal, p_saxis, p_taxis;
float distinv;
TransformVector (r_polydesc.vpn, p_normal);
TransformVector (r_polydesc.vright, p_saxis);
TransformVector (r_polydesc.vup, p_taxis);
distinv = 1.0 / (-(DotProduct (r_polydesc.viewer_position, r_polydesc.vpn)) + r_polydesc.dist );
d_sdivzstepu = p_saxis[0] * xscaleinv;
d_sdivzstepv = -p_saxis[1] * yscaleinv;
d_sdivzorigin = p_saxis[2] - xcenter * d_sdivzstepu - ycenter * d_sdivzstepv;
d_tdivzstepu = p_taxis[0] * xscaleinv;
d_tdivzstepv = -p_taxis[1] * yscaleinv;
d_tdivzorigin = p_taxis[2] - xcenter * d_tdivzstepu - ycenter * d_tdivzstepv;
d_zistepu = p_normal[0] * xscaleinv * distinv;
d_zistepv = -p_normal[1] * yscaleinv * distinv;
d_ziorigin = p_normal[2] * distinv - xcenter * d_zistepu - ycenter * d_zistepv;
sadjust = (fixed16_t) ( ( DotProduct( r_polydesc.viewer_position, r_polydesc.vright) + r_polydesc.s_offset ) * 0x10000 );
tadjust = (fixed16_t) ( ( DotProduct( r_polydesc.viewer_position, r_polydesc.vup ) + r_polydesc.t_offset ) * 0x10000 );
// -1 (-epsilon) so we never wander off the edge of the texture
bbextents = (r_polydesc.pixel_width << 16) - 1;
bbextentt = (r_polydesc.pixel_height << 16) - 1;
}
/*
** R_DrawPoly
**
** Polygon drawing function. Uses the polygon described in r_polydesc
** to calculate edges and gradients, then renders the resultant spans.
**
** This should NOT be called externally since it doesn't do clipping!
*/
static void R_DrawPoly( qboolean iswater )
{
int i, nump;
float ymin, ymax;
emitpoint_t *pverts;
espan_t spans[MAXHEIGHT+1];
s_polygon_spans = spans;
// find the top and bottom vertices, and make sure there's at least one scan to
// draw
ymin = 999999.9;
ymax = -999999.9;
pverts = r_polydesc.pverts;
for (i=0 ; i<r_polydesc.nump ; i++)
{
if (pverts->v < ymin)
{
ymin = pverts->v;
s_minindex = i;
}
if (pverts->v > ymax)
{
ymax = pverts->v;
s_maxindex = i;
}
pverts++;
}
ymin = ceil (ymin);
ymax = ceil (ymax);
if (ymin >= ymax)
return; // doesn't cross any scans at all
cachewidth = r_polydesc.pixel_width;
cacheblock = r_polydesc.pixels;
// copy the first vertex to the last vertex, so we don't have to deal with
// wrapping
nump = r_polydesc.nump;
pverts = r_polydesc.pverts;
pverts[nump] = pverts[0];
R_PolygonCalculateGradients ();
R_PolygonScanLeftEdge ();
R_PolygonScanRightEdge ();
R_PolygonDrawSpans( s_polygon_spans, iswater );
}
/*
** R_DrawAlphaSurfaces
*/
void R_DrawAlphaSurfaces( void )
{
msurface_t *s = r_alpha_surfaces;
currentmodel = r_worldmodel;
modelorg[0] = -r_origin[0];
modelorg[1] = -r_origin[1];
modelorg[2] = -r_origin[2];
while ( s )
{
R_BuildPolygonFromSurface( s );
if (s->texinfo->flags & SURF_TRANS66)
R_ClipAndDrawPoly( 0.60f, ( s->texinfo->flags & SURF_WARP) != 0, true );
else
R_ClipAndDrawPoly( 0.30f, ( s->texinfo->flags & SURF_WARP) != 0, true );
s = s->nextalphasurface;
}
r_alpha_surfaces = NULL;
}
/*
** R_IMFlatShadedQuad
*/
void R_IMFlatShadedQuad( vec3_t a, vec3_t b, vec3_t c, vec3_t d, int color, float alpha )
{
vec3_t s0, s1;
r_polydesc.nump = 4;
VectorCopy( r_origin, r_polydesc.viewer_position );
VectorCopy( a, r_clip_verts[0][0] );
VectorCopy( b, r_clip_verts[0][1] );
VectorCopy( c, r_clip_verts[0][2] );
VectorCopy( d, r_clip_verts[0][3] );
r_clip_verts[0][0][3] = 0;
r_clip_verts[0][1][3] = 0;
r_clip_verts[0][2][3] = 0;
r_clip_verts[0][3][3] = 0;
r_clip_verts[0][0][4] = 0;
r_clip_verts[0][1][4] = 0;
r_clip_verts[0][2][4] = 0;
r_clip_verts[0][3][4] = 0;
VectorSubtract( d, c, s0 );
VectorSubtract( c, b, s1 );
CrossProduct( s0, s1, r_polydesc.vpn );
VectorNormalize( r_polydesc.vpn );
r_polydesc.dist = DotProduct( r_polydesc.vpn, r_clip_verts[0][0] );
r_polyblendcolor = color;
R_ClipAndDrawPoly( alpha, false, false );
}