/quakeforge/trunk/libs/video/renderer/sw/d_sprite.c
C | 418 lines | 288 code | 80 blank | 50 comment | 58 complexity | 4bafd8ff377cbbd58971837acf1b05af MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.1, AGPL-3.0, AGPL-1.0, Unlicense
- /*
- 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
- static __attribute__ ((used)) const char rcsid[] =
- "$Id: d_sprite.c 11379 2007-03-10 12:00:59Z taniwha $";
- #include "QF/render.h"
- #include "d_local.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 = (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
- 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 (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);
- VectorNegate (p_taxis, 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;
- }
- 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 = &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);
- }