newtree/source/d_scan.c

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/*
d_scan.c
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Portable C scan-level rasterization code, all pixel depths.
Copyright (C) 1996-1997 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:
Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307, USA
$Id$
*/
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#ifdef HAVE_CONFIG_H
# include "config.h"
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#endif
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#include "d_local.h"
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#include "r_local.h"
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unsigned char *r_turb_pbase, *r_turb_pdest;
fixed16_t r_turb_s, r_turb_t, r_turb_sstep, r_turb_tstep;
int *r_turb_turb;
int r_turb_spancount;
void D_DrawTurbulent8Span (void);
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/*
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D_WarpScreen
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this performs a slight compression of the screen at the same time as
the sine warp, to keep the edges from wrapping
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*/
void
D_WarpScreen (void)
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{
int w, h;
int u, v;
byte *dest;
int *turb;
int *col;
byte **row;
byte *rowptr[1024];
int column[1280];
float wratio, hratio;
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w = r_refdef.vrect.width;
h = r_refdef.vrect.height;
wratio = w / (float) scr_vrect.width;
hratio = h / (float) scr_vrect.height;
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for (v = 0; v < scr_vrect.height + AMP2 * 2; v++) {
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rowptr[v] = d_viewbuffer + (r_refdef.vrect.y * screenwidth) +
(screenwidth * (int) ((float) v * hratio * h / (h + AMP2 * 2)));
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}
for (u = 0; u < scr_vrect.width + AMP2 * 2; u++) {
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column[u] = r_refdef.vrect.x +
(int) ((float) u * wratio * w / (w + AMP2 * 2));
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}
turb = intsintable + ((int) (cl.time * SPEED) & (CYCLE - 1));
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dest = vid.buffer + scr_vrect.y * vid.rowbytes + scr_vrect.x;
for (v = 0; v < scr_vrect.height; v++, dest += vid.rowbytes) {
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col = &column[turb[v]];
row = &rowptr[v];
for (u = 0; u < scr_vrect.width; u += 4) {
dest[u + 0] = row[turb[u + 0]][col[u + 0]];
dest[u + 1] = row[turb[u + 1]][col[u + 1]];
dest[u + 2] = row[turb[u + 2]][col[u + 2]];
dest[u + 3] = row[turb[u + 3]][col[u + 3]];
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}
}
}
#ifndef USE_INTEL_ASM
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/*
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D_DrawTurbulent8Span
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*/
void
D_DrawTurbulent8Span (void)
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{
int sturb, tturb;
do {
sturb =
((r_turb_s + r_turb_turb[(r_turb_t >> 16) & (CYCLE - 1)]) >> 16) &
63;
tturb =
((r_turb_t + r_turb_turb[(r_turb_s >> 16) & (CYCLE - 1)]) >> 16) &
63;
*r_turb_pdest++ = *(r_turb_pbase + (tturb << 6) + sturb);
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r_turb_s += r_turb_sstep;
r_turb_t += r_turb_tstep;
} while (--r_turb_spancount > 0);
}
#endif // !USE_INTEL_ASM
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/*
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Turbulent8
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*/
void
Turbulent8 (espan_t *pspan)
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{
int count;
fixed16_t snext, tnext;
float sdivz, tdivz, zi, z, du, dv, spancountminus1;
float sdivz16stepu, tdivz16stepu, zi16stepu;
r_turb_turb = sintable + ((int) (cl.time * SPEED) & (CYCLE - 1));
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r_turb_sstep = 0; // keep compiler happy
r_turb_tstep = 0; // ditto
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r_turb_pbase = (unsigned char *) cacheblock;
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sdivz16stepu = d_sdivzstepu * 16;
tdivz16stepu = d_tdivzstepu * 16;
zi16stepu = d_zistepu * 16;
do {
r_turb_pdest = (unsigned char *) ((byte *) d_viewbuffer +
(screenwidth * pspan->v) + pspan->u);
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count = pspan->count;
// calculate the initial s/z, t/z, 1/z, s, and t and clamp
du = (float) pspan->u;
dv = (float) pspan->v;
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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
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r_turb_s = (int) (sdivz * z) + sadjust;
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if (r_turb_s > bbextents)
r_turb_s = bbextents;
else if (r_turb_s < 0)
r_turb_s = 0;
r_turb_t = (int) (tdivz * z) + tadjust;
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if (r_turb_t > bbextentt)
r_turb_t = bbextentt;
else if (r_turb_t < 0)
r_turb_t = 0;
do {
// calculate s and t at the far end of the span
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if (count >= 16)
r_turb_spancount = 16;
else
r_turb_spancount = count;
count -= r_turb_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
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sdivz += sdivz16stepu;
tdivz += tdivz16stepu;
zi += zi16stepu;
z = (float) 0x10000 / zi; // prescale to 16.16 fixed-point
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snext = (int) (sdivz * z) + sadjust;
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if (snext > bbextents)
snext = bbextents;
else if (snext < 16)
snext = 16; // prevent round-off error on <0
// steps from
// from causing overstepping & running off the
// edge of the texture
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tnext = (int) (tdivz * z) + tadjust;
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if (tnext > bbextentt)
tnext = bbextentt;
else if (tnext < 16)
tnext = 16; // guard against round-off error on
// <0 steps
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r_turb_sstep = (snext - r_turb_s) >> 4;
r_turb_tstep = (tnext - r_turb_t) >> 4;
} 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) (r_turb_spancount - 1);
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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;
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if (snext > bbextents)
snext = bbextents;
else if (snext < 16)
snext = 16; // prevent round-off error on <0
// steps from
// from causing overstepping & running off the
// edge of the texture
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tnext = (int) (tdivz * z) + tadjust;
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if (tnext > bbextentt)
tnext = bbextentt;
else if (tnext < 16)
tnext = 16; // guard against round-off error on
// <0 steps
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if (r_turb_spancount > 1) {
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r_turb_sstep = (snext - r_turb_s) / (r_turb_spancount - 1);
r_turb_tstep = (tnext - r_turb_t) / (r_turb_spancount - 1);
}
}
r_turb_s = r_turb_s & ((CYCLE << 16) - 1);
r_turb_t = r_turb_t & ((CYCLE << 16) - 1);
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D_DrawTurbulent8Span ();
r_turb_s = snext;
r_turb_t = tnext;
} while (count > 0);
} while ((pspan = pspan->pnext) != NULL);
}
#ifndef USE_INTEL_ASM
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/*
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D_DrawSpans8
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*/
void
D_DrawSpans8 (espan_t *pspan)
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{
int count, spancount;
unsigned char *pbase, *pdest;
fixed16_t s, t, snext, tnext, sstep, tstep;
float sdivz, tdivz, zi, z, du, dv, spancountminus1;
float sdivz8stepu, tdivz8stepu, zi8stepu;
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sstep = 0; // keep compiler happy
tstep = 0; // ditto
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pbase = (unsigned char *) cacheblock;
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sdivz8stepu = d_sdivzstepu * 8;
tdivz8stepu = d_tdivzstepu * 8;
zi8stepu = d_zistepu * 8;
do {
pdest = (unsigned char *) ((byte *) d_viewbuffer +
(screenwidth * pspan->v) + pspan->u);
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count = pspan->count;
// calculate the initial s/z, t/z, 1/z, s, and t and clamp
du = (float) pspan->u;
dv = (float) pspan->v;
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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
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s = (int) (sdivz * z) + sadjust;
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if (s > bbextents)
s = bbextents;
else if (s < 0)
s = 0;
t = (int) (tdivz * z) + tadjust;
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if (t > bbextentt)
t = bbextentt;
else if (t < 0)
t = 0;
do {
// calculate s and t at the far end of the span
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if (count >= 8)
spancount = 8;
else
spancount = count;
count -= 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
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sdivz += sdivz8stepu;
tdivz += tdivz8stepu;
zi += zi8stepu;
z = (float) 0x10000 / zi; // prescale to 16.16 fixed-point
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snext = (int) (sdivz * z) + sadjust;
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if (snext > bbextents)
snext = bbextents;
else if (snext < 8)
snext = 8; // prevent round-off error on <0
// steps from
// from causing overstepping & running off the
// edge of the texture
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tnext = (int) (tdivz * z) + tadjust;
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if (tnext > bbextentt)
tnext = bbextentt;
else if (tnext < 8)
tnext = 8; // guard against round-off error on
// <0 steps
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sstep = (snext - s) >> 3;
tstep = (tnext - t) >> 3;
} 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) (spancount - 1);
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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;
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if (snext > bbextents)
snext = bbextents;
else if (snext < 8)
snext = 8; // prevent round-off error on <0
// steps from
// from causing overstepping & running off the
// edge of the texture
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tnext = (int) (tdivz * z) + tadjust;
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if (tnext > bbextentt)
tnext = bbextentt;
else if (tnext < 8)
tnext = 8; // guard against round-off error on
// <0 steps
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if (spancount > 1) {
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sstep = (snext - s) / (spancount - 1);
tstep = (tnext - t) / (spancount - 1);
}
}
do {
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*pdest++ = *(pbase + (s >> 16) + (t >> 16) * cachewidth);
s += sstep;
t += tstep;
} while (--spancount > 0);
s = snext;
t = tnext;
} while (count > 0);
} while ((pspan = pspan->pnext) != NULL);
}
#endif
#ifndef USE_INTEL_ASM
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/*
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D_DrawZSpans
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*/
void
D_DrawZSpans (espan_t *pspan)
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{
int count, doublecount, izistep;
int izi;
short *pdest;
unsigned int ltemp;
double zi;
float du, dv;
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// FIXME: check for clamping/range problems
// we count on FP exceptions being turned off to avoid range problems
izistep = (int) (d_zistepu * 0x8000 * 0x10000);
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do {
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pdest = d_pzbuffer + (d_zwidth * pspan->v) + pspan->u;
count = pspan->count;
// calculate the initial 1/z
du = (float) pspan->u;
dv = (float) pspan->v;
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zi = d_ziorigin + dv * d_zistepv + du * d_zistepu;
// we count on FP exceptions being turned off to avoid range problems
izi = (int) (zi * 0x8000 * 0x10000);
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if ((long) pdest & 0x02) {
*pdest++ = (short) (izi >> 16);
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izi += izistep;
count--;
}
if ((doublecount = count >> 1) > 0) {
do {
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ltemp = izi >> 16;
izi += izistep;
ltemp |= izi & 0xFFFF0000;
izi += izistep;
*(int *) pdest = ltemp;
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pdest += 2;
} while (--doublecount > 0);
}
if (count & 1)
*pdest = (short) (izi >> 16);
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} while ((pspan = pspan->pnext) != NULL);
}
#endif