442 lines
9.9 KiB
C
442 lines
9.9 KiB
C
/*
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Copyright (C) 1996-1997 Id Software, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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// d_sprite.c: software top-level rasterization driver module for drawing
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// sprites
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#include "quakedef.h"
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#include "d_local.h"
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static int sprite_height;
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static int minindex, maxindex;
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static sspan_t *sprite_spans;
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#if !id386
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/*
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=====================
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D_SpriteDrawSpans
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=====================
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*/
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void D_SpriteDrawSpans (sspan_t *pspan)
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{
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int count, spancount, izistep;
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int izi;
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byte *pbase, *pdest;
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fixed16_t s, t, snext, tnext, sstep, tstep;
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float sdivz, tdivz, zi, z, du, dv, spancountminus1;
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float sdivz8stepu, tdivz8stepu, zi8stepu;
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byte btemp;
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short *pz;
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sstep = 0; // keep compiler happy
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tstep = 0; // ditto
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pbase = cacheblock;
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sdivz8stepu = d_sdivzstepu * 8;
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tdivz8stepu = d_tdivzstepu * 8;
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zi8stepu = d_zistepu * 8;
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// we count on FP exceptions being turned off to avoid range problems
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izistep = (int)(d_zistepu * 0x8000 * 0x10000);
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do
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{
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pdest = (byte *)d_viewbuffer + (screenwidth * pspan->v) + pspan->u;
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pz = d_pzbuffer + (d_zwidth * pspan->v) + pspan->u;
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count = pspan->count;
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if (count <= 0)
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goto NextSpan;
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// calculate the initial s/z, t/z, 1/z, s, and t and clamp
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du = (float)pspan->u;
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dv = (float)pspan->v;
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sdivz = d_sdivzorigin + dv*d_sdivzstepv + du*d_sdivzstepu;
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tdivz = d_tdivzorigin + dv*d_tdivzstepv + du*d_tdivzstepu;
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zi = d_ziorigin + dv*d_zistepv + du*d_zistepu;
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z = (float)0x10000 / zi; // prescale to 16.16 fixed-point
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// we count on FP exceptions being turned off to avoid range problems
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izi = (int)(zi * 0x8000 * 0x10000);
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s = (int)(sdivz * z) + sadjust;
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if (s > bbextents)
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s = bbextents;
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else if (s < 0)
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s = 0;
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t = (int)(tdivz * z) + tadjust;
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if (t > bbextentt)
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t = bbextentt;
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else if (t < 0)
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t = 0;
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do
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{
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// calculate s and t at the far end of the span
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if (count >= 8)
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spancount = 8;
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else
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spancount = count;
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count -= spancount;
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if (count)
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{
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// calculate s/z, t/z, zi->fixed s and t at far end of span,
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// calculate s and t steps across span by shifting
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sdivz += sdivz8stepu;
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tdivz += tdivz8stepu;
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zi += zi8stepu;
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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)
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snext = bbextents;
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else if (snext < 8)
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snext = 8; // prevent round-off error on <0 steps from
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// from causing overstepping & running off the
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// edge of the texture
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tnext = (int)(tdivz * z) + tadjust;
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if (tnext > bbextentt)
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tnext = bbextentt;
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else if (tnext < 8)
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tnext = 8; // guard against round-off error on <0 steps
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sstep = (snext - s) >> 3;
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tstep = (tnext - t) >> 3;
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}
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else
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{
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// calculate s/z, t/z, zi->fixed s and t at last pixel in span (so
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// can't step off polygon), clamp, calculate s and t steps across
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// span by division, biasing steps low so we don't run off the
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// texture
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spancountminus1 = (float)(spancount - 1);
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sdivz += d_sdivzstepu * spancountminus1;
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tdivz += d_tdivzstepu * spancountminus1;
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zi += d_zistepu * spancountminus1;
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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)
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snext = bbextents;
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else if (snext < 8)
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snext = 8; // prevent round-off error on <0 steps from
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// from causing overstepping & running off the
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// edge of the texture
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tnext = (int)(tdivz * z) + tadjust;
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if (tnext > bbextentt)
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tnext = bbextentt;
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else if (tnext < 8)
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tnext = 8; // guard against round-off error on <0 steps
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if (spancount > 1)
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{
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sstep = (snext - s) / (spancount - 1);
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tstep = (tnext - t) / (spancount - 1);
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}
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}
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do
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{
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btemp = *(pbase + (s >> 16) + (t >> 16) * cachewidth);
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if (btemp != 255)
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{
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if (*pz <= (izi >> 16))
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{
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*pz = izi >> 16;
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*pdest = btemp;
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}
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}
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izi += izistep;
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pdest++;
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pz++;
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s += sstep;
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t += tstep;
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} while (--spancount > 0);
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s = snext;
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t = tnext;
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} while (count > 0);
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NextSpan:
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pspan++;
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} while (pspan->count != DS_SPAN_LIST_END);
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}
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#endif
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/*
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=====================
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D_SpriteScanLeftEdge
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=====================
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*/
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void D_SpriteScanLeftEdge (void)
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{
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int i, v, itop, ibottom, lmaxindex;
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emitpoint_t *pvert, *pnext;
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sspan_t *pspan;
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float du, dv, vtop, vbottom, slope;
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fixed16_t u, u_step;
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pspan = sprite_spans;
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i = minindex;
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if (i == 0)
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i = r_spritedesc.nump;
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lmaxindex = maxindex;
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if (lmaxindex == 0)
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lmaxindex = r_spritedesc.nump;
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vtop = ceil (r_spritedesc.pverts[i].v);
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do
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{
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pvert = &r_spritedesc.pverts[i];
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pnext = pvert - 1;
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vbottom = ceil (pnext->v);
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if (vtop < vbottom)
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{
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du = pnext->u - pvert->u;
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dv = pnext->v - pvert->v;
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slope = du / dv;
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u_step = (int)(slope * 0x10000);
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// adjust u to ceil the integer portion
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u = (int)((pvert->u + (slope * (vtop - pvert->v))) * 0x10000) +
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(0x10000 - 1);
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itop = (int)vtop;
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ibottom = (int)vbottom;
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for (v=itop ; v<ibottom ; v++)
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{
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pspan->u = u >> 16;
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pspan->v = v;
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u += u_step;
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pspan++;
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}
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}
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vtop = vbottom;
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i--;
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if (i == 0)
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i = r_spritedesc.nump;
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} while (i != lmaxindex);
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}
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/*
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=====================
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D_SpriteScanRightEdge
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=====================
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*/
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void D_SpriteScanRightEdge (void)
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{
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int i, v, itop, ibottom;
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emitpoint_t *pvert, *pnext;
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sspan_t *pspan;
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float du, dv, vtop, vbottom, slope, uvert, unext, vvert, vnext;
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fixed16_t u, u_step;
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pspan = sprite_spans;
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i = minindex;
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vvert = r_spritedesc.pverts[i].v;
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if (vvert < r_refdef.fvrecty_adj)
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vvert = r_refdef.fvrecty_adj;
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if (vvert > r_refdef.fvrectbottom_adj)
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vvert = r_refdef.fvrectbottom_adj;
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vtop = ceil (vvert);
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do
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{
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pvert = &r_spritedesc.pverts[i];
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pnext = pvert + 1;
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vnext = pnext->v;
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if (vnext < r_refdef.fvrecty_adj)
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vnext = r_refdef.fvrecty_adj;
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if (vnext > r_refdef.fvrectbottom_adj)
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vnext = r_refdef.fvrectbottom_adj;
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vbottom = ceil (vnext);
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if (vtop < vbottom)
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{
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uvert = pvert->u;
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if (uvert < r_refdef.fvrectx_adj)
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uvert = r_refdef.fvrectx_adj;
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if (uvert > r_refdef.fvrectright_adj)
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uvert = r_refdef.fvrectright_adj;
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unext = pnext->u;
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if (unext < r_refdef.fvrectx_adj)
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unext = r_refdef.fvrectx_adj;
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if (unext > r_refdef.fvrectright_adj)
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unext = r_refdef.fvrectright_adj;
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du = unext - uvert;
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dv = vnext - vvert;
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slope = du / dv;
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u_step = (int)(slope * 0x10000);
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// adjust u to ceil the integer portion
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u = (int)((uvert + (slope * (vtop - vvert))) * 0x10000) +
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(0x10000 - 1);
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itop = (int)vtop;
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ibottom = (int)vbottom;
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for (v=itop ; v<ibottom ; v++)
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{
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pspan->count = (u >> 16) - pspan->u;
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u += u_step;
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pspan++;
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}
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}
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vtop = vbottom;
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vvert = vnext;
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i++;
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if (i == r_spritedesc.nump)
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i = 0;
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} while (i != maxindex);
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pspan->count = DS_SPAN_LIST_END; // mark the end of the span list
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}
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/*
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=====================
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D_SpriteCalculateGradients
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=====================
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*/
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void D_SpriteCalculateGradients (void)
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{
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vec3_t p_normal, p_saxis, p_taxis, p_temp1;
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float distinv;
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TransformVector (r_spritedesc.vpn, p_normal);
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TransformVector (r_spritedesc.vright, p_saxis);
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TransformVector (r_spritedesc.vup, p_taxis);
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VectorInverse (p_taxis);
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distinv = 1.0 / (-DotProduct (modelorg, r_spritedesc.vpn));
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d_sdivzstepu = p_saxis[0] * xscaleinv;
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d_tdivzstepu = p_taxis[0] * xscaleinv;
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d_sdivzstepv = -p_saxis[1] * yscaleinv;
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d_tdivzstepv = -p_taxis[1] * yscaleinv;
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d_zistepu = p_normal[0] * xscaleinv * distinv;
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d_zistepv = -p_normal[1] * yscaleinv * distinv;
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d_sdivzorigin = p_saxis[2] - xcenter * d_sdivzstepu -
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ycenter * d_sdivzstepv;
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d_tdivzorigin = p_taxis[2] - xcenter * d_tdivzstepu -
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ycenter * d_tdivzstepv;
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d_ziorigin = p_normal[2] * distinv - xcenter * d_zistepu -
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ycenter * d_zistepv;
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TransformVector (modelorg, p_temp1);
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sadjust = ((fixed16_t)(DotProduct (p_temp1, p_saxis) * 0x10000 + 0.5)) -
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(-(cachewidth >> 1) << 16);
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tadjust = ((fixed16_t)(DotProduct (p_temp1, p_taxis) * 0x10000 + 0.5)) -
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(-(sprite_height >> 1) << 16);
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// -1 (-epsilon) so we never wander off the edge of the texture
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bbextents = (cachewidth << 16) - 1;
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bbextentt = (sprite_height << 16) - 1;
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}
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/*
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=====================
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D_DrawSprite
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=====================
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*/
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void D_DrawSprite (void)
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{
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int i, nump;
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float ymin, ymax;
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emitpoint_t *pverts;
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sspan_t spans[MAXHEIGHT+1];
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sprite_spans = spans;
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// find the top and bottom vertices, and make sure there's at least one scan to
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// draw
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ymin = 999999.9;
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ymax = -999999.9;
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pverts = r_spritedesc.pverts;
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for (i=0 ; i<r_spritedesc.nump ; i++)
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{
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if (pverts->v < ymin)
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{
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ymin = pverts->v;
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minindex = i;
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}
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if (pverts->v > ymax)
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{
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ymax = pverts->v;
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maxindex = i;
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}
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pverts++;
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}
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ymin = ceil (ymin);
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ymax = ceil (ymax);
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if (ymin >= ymax)
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return; // doesn't cross any scans at all
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cachewidth = r_spritedesc.pspriteframe->width;
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sprite_height = r_spritedesc.pspriteframe->height;
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cacheblock = (byte *)&r_spritedesc.pspriteframe->pixels[0];
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// copy the first vertex to the last vertex, so we don't have to deal with
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// wrapping
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nump = r_spritedesc.nump;
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pverts = r_spritedesc.pverts;
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pverts[nump] = pverts[0];
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D_SpriteCalculateGradients ();
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D_SpriteScanLeftEdge ();
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D_SpriteScanRightEdge ();
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D_SpriteDrawSpans (sprite_spans);
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}
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