quakeforge-old/uquake/d_sprite.c
Jeff Teunissen c3f5581b0a Created new subdir: uquake. Pick your favorite U word for the meaning --
Unchained, Ultimate, Ultra, Up Yours, Underworld, Underground, Unified,
Unity, etc. You know the drill.

This takes care of the "standalone" problem with the wrong name, and the
recent snafu with multiple developers working on the same files
simultaneously...expect me (and probably others) to start locking dirs when
updates are taking place.

And yes, this update is really as large as it looks. Software only at the
moment, but I will have the makefile updated to build the GL builds as
well.
1999-12-26 13:51:52 +00:00

442 lines
9.9 KiB
C

/*
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 the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
// d_sprite.c: software top-level rasterization driver module for drawing
// sprites
#include "quakedef.h"
#include "d_local.h"
static int sprite_height;
static int minindex, maxindex;
static sspan_t *sprite_spans;
#if !id386
/*
=====================
D_SpriteDrawSpans
=====================
*/
void D_SpriteDrawSpans (sspan_t *pspan)
{
int count, spancount, izistep;
int izi;
byte *pbase, *pdest;
fixed16_t s, t, snext, tnext, sstep, tstep;
float sdivz, tdivz, zi, z, du, dv, spancountminus1;
float sdivz8stepu, tdivz8stepu, zi8stepu;
byte btemp;
short *pz;
sstep = 0; // keep compiler happy
tstep = 0; // ditto
pbase = cacheblock;
sdivz8stepu = d_sdivzstepu * 8;
tdivz8stepu = d_tdivzstepu * 8;
zi8stepu = d_zistepu * 8;
// we count on FP exceptions being turned off to avoid range problems
izistep = (int)(d_zistepu * 0x8000 * 0x10000);
do
{
pdest = (byte *)d_viewbuffer + (screenwidth * pspan->v) + pspan->u;
pz = d_pzbuffer + (d_zwidth * pspan->v) + pspan->u;
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
izi = (int)(zi * 0x8000 * 0x10000);
s = (int)(sdivz * z) + sadjust;
if (s > bbextents)
s = bbextents;
else if (s < 0)
s = 0;
t = (int)(tdivz * z) + tadjust;
if (t > bbextentt)
t = bbextentt;
else if (t < 0)
t = 0;
do
{
// calculate s and t at the far end of the span
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
sdivz += sdivz8stepu;
tdivz += tdivz8stepu;
zi += zi8stepu;
z = (float)0x10000 / zi; // prescale to 16.16 fixed-point
snext = (int)(sdivz * z) + sadjust;
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
tnext = (int)(tdivz * z) + tadjust;
if (tnext > bbextentt)
tnext = bbextentt;
else if (tnext < 8)
tnext = 8; // guard against round-off error on <0 steps
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);
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;
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
tnext = (int)(tdivz * z) + tadjust;
if (tnext > bbextentt)
tnext = bbextentt;
else if (tnext < 8)
tnext = 8; // guard against round-off error on <0 steps
if (spancount > 1)
{
sstep = (snext - s) / (spancount - 1);
tstep = (tnext - t) / (spancount - 1);
}
}
do
{
btemp = *(pbase + (s >> 16) + (t >> 16) * cachewidth);
if (btemp != 255)
{
if (*pz <= (izi >> 16))
{
*pz = izi >> 16;
*pdest = btemp;
}
}
izi += izistep;
pdest++;
pz++;
s += sstep;
t += tstep;
} while (--spancount > 0);
s = snext;
t = tnext;
} while (count > 0);
NextSpan:
pspan++;
} while (pspan->count != DS_SPAN_LIST_END);
}
#endif
/*
=====================
D_SpriteScanLeftEdge
=====================
*/
void D_SpriteScanLeftEdge (void)
{
int i, v, itop, ibottom, lmaxindex;
emitpoint_t *pvert, *pnext;
sspan_t *pspan;
float du, dv, vtop, vbottom, slope;
fixed16_t u, u_step;
pspan = sprite_spans;
i = minindex;
if (i == 0)
i = r_spritedesc.nump;
lmaxindex = maxindex;
if (lmaxindex == 0)
lmaxindex = r_spritedesc.nump;
vtop = ceil (r_spritedesc.pverts[i].v);
do
{
pvert = &r_spritedesc.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_spritedesc.nump;
} while (i != lmaxindex);
}
/*
=====================
D_SpriteScanRightEdge
=====================
*/
void D_SpriteScanRightEdge (void)
{
int i, v, itop, ibottom;
emitpoint_t *pvert, *pnext;
sspan_t *pspan;
float du, dv, vtop, vbottom, slope, uvert, unext, vvert, vnext;
fixed16_t u, u_step;
pspan = sprite_spans;
i = minindex;
vvert = r_spritedesc.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_spritedesc.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_spritedesc.nump)
i = 0;
} while (i != maxindex);
pspan->count = DS_SPAN_LIST_END; // mark the end of the span list
}
/*
=====================
D_SpriteCalculateGradients
=====================
*/
void D_SpriteCalculateGradients (void)
{
vec3_t p_normal, p_saxis, p_taxis, p_temp1;
float distinv;
TransformVector (r_spritedesc.vpn, p_normal);
TransformVector (r_spritedesc.vright, p_saxis);
TransformVector (r_spritedesc.vup, p_taxis);
VectorInverse (p_taxis);
distinv = 1.0 / (-DotProduct (modelorg, r_spritedesc.vpn));
d_sdivzstepu = p_saxis[0] * xscaleinv;
d_tdivzstepu = p_taxis[0] * xscaleinv;
d_sdivzstepv = -p_saxis[1] * yscaleinv;
d_tdivzstepv = -p_taxis[1] * yscaleinv;
d_zistepu = p_normal[0] * xscaleinv * distinv;
d_zistepv = -p_normal[1] * yscaleinv * distinv;
d_sdivzorigin = p_saxis[2] - xcenter * d_sdivzstepu -
ycenter * d_sdivzstepv;
d_tdivzorigin = p_taxis[2] - xcenter * d_tdivzstepu -
ycenter * d_tdivzstepv;
d_ziorigin = p_normal[2] * distinv - xcenter * d_zistepu -
ycenter * d_zistepv;
TransformVector (modelorg, p_temp1);
sadjust = ((fixed16_t)(DotProduct (p_temp1, p_saxis) * 0x10000 + 0.5)) -
(-(cachewidth >> 1) << 16);
tadjust = ((fixed16_t)(DotProduct (p_temp1, p_taxis) * 0x10000 + 0.5)) -
(-(sprite_height >> 1) << 16);
// -1 (-epsilon) so we never wander off the edge of the texture
bbextents = (cachewidth << 16) - 1;
bbextentt = (sprite_height << 16) - 1;
}
/*
=====================
D_DrawSprite
=====================
*/
void D_DrawSprite (void)
{
int i, nump;
float ymin, ymax;
emitpoint_t *pverts;
sspan_t spans[MAXHEIGHT+1];
sprite_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_spritedesc.pverts;
for (i=0 ; i<r_spritedesc.nump ; i++)
{
if (pverts->v < ymin)
{
ymin = pverts->v;
minindex = i;
}
if (pverts->v > ymax)
{
ymax = pverts->v;
maxindex = i;
}
pverts++;
}
ymin = ceil (ymin);
ymax = ceil (ymax);
if (ymin >= ymax)
return; // doesn't cross any scans at all
cachewidth = r_spritedesc.pspriteframe->width;
sprite_height = r_spritedesc.pspriteframe->height;
cacheblock = (byte *)&r_spritedesc.pspriteframe->pixels[0];
// copy the first vertex to the last vertex, so we don't have to deal with
// wrapping
nump = r_spritedesc.nump;
pverts = r_spritedesc.pverts;
pverts[nump] = pverts[0];
D_SpriteCalculateGradients ();
D_SpriteScanLeftEdge ();
D_SpriteScanRightEdge ();
D_SpriteDrawSpans (sprite_spans);
}