quakeforge/libs/video/renderer/sw/d_sprite.c
Bill Currie 0c437492b4 [renderer] Move to using dynamic frame buffers
For now, OpenGL and Vulkan renderers are broken as I focused on getting
the software renderer working (which was quite tricky to get right).

This fixes a couple of issues: the segfault when warping the screen (due
to the scene rendering move invalidating the warp buffer), and warp
always having 320x200 resolution. There's still the problem of the
effect being too subtle at high resolution, but that's just a matter of
updating the tables and tweaking the code in D_WarpScreen.

Another issue is the Draw functions should probably write directly to
the main frame buffer or even one passed in as a parameter. This would
remove the need for binding the main buffer at the beginning and end of
the frame.
2022-03-24 12:56:29 +09:00

416 lines
9.9 KiB
C

/*
d_sprite.c
software top-level rasterization driver module for drawing sprites
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
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "QF/render.h"
#include "d_local.h"
#include "r_internal.h"
static int sprite_height;
static int minindex, maxindex;
static sspan_t *sprite_spans;
#ifdef PIC
#undef USE_INTEL_ASM //XXX asm pic hack
#endif
#ifndef USE_INTEL_ASM
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 = d_viewbuffer + (d_rowbytes * pspan->v) + pspan->u;
pz = d_zbuffer + (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
static 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);
}
static 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
}
static void
D_SpriteCalculateGradients (const vec3_t relvieworg)
{
vec3_t p_normal, p_saxis, p_taxis, p_temp1;
float distinv;
TransformVector (r_spritedesc.vfwd, p_normal);
TransformVector (r_spritedesc.vright, p_saxis);
TransformVector (r_spritedesc.vup, p_taxis);
VectorNegate (p_taxis, p_taxis);
distinv = 1.0 / (-DotProduct (relvieworg, r_spritedesc.vfwd));
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 (relvieworg, 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;
}
void
D_DrawSprite (const vec3_t relvieworg)
{
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 = &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 (relvieworg);
D_SpriteScanLeftEdge ();
D_SpriteScanRightEdge ();
D_SpriteDrawSpans (sprite_spans);
}