mirror of
https://git.code.sf.net/p/quake/newtree
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143 lines
3.3 KiB
C
143 lines
3.3 KiB
C
/*
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d_sky.c
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(description)
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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:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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$Id$
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*/
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#ifdef HAVE_CONFIG_H
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# 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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#define SKY_SPAN_SHIFT 5
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#define SKY_SPAN_MAX (1 << SKY_SPAN_SHIFT)
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/*
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=================
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D_Sky_uv_To_st
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=================
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*/
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void
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D_Sky_uv_To_st (int u, int v, fixed16_t *s, fixed16_t *t)
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{
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float wu, wv, temp;
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vec3_t end;
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if (r_refdef.vrect.width >= r_refdef.vrect.height)
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temp = (float) r_refdef.vrect.width;
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else
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temp = (float) r_refdef.vrect.height;
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wu = 8192.0 * (float) (u - ((int) vid.width >> 1)) / temp;
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wv = 8192.0 * (float) (((int) vid.height >> 1) - v) / temp;
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end[0] = 4096 * vpn[0] + wu * vright[0] + wv * vup[0];
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end[1] = 4096 * vpn[1] + wu * vright[1] + wv * vup[1];
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end[2] = 4096 * vpn[2] + wu * vright[2] + wv * vup[2];
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end[2] *= 3;
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VectorNormalize (end);
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temp = skytime * skyspeed; // TODO: add D_SetupFrame & set this
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// there
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*s = (int) ((temp + 6 * (SKYSIZE / 2 - 1) * end[0]) * 0x10000);
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*t = (int) ((temp + 6 * (SKYSIZE / 2 - 1) * end[1]) * 0x10000);
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}
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/*
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=================
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D_DrawSkyScans8
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=================
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*/
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void
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D_DrawSkyScans8 (espan_t *pspan)
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{
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int count, spancount, u, v;
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unsigned char *pdest;
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fixed16_t s, t, snext, tnext, sstep, tstep;
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int spancountminus1;
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sstep = 0; // keep compiler happy
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tstep = 0; // ditto
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do {
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pdest = (unsigned char *) ((byte *) d_viewbuffer +
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(screenwidth * pspan->v) + pspan->u);
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count = pspan->count;
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// calculate the initial s & t
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u = pspan->u;
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v = pspan->v;
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D_Sky_uv_To_st (u, v, &s, &t);
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do {
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if (count >= SKY_SPAN_MAX)
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spancount = SKY_SPAN_MAX;
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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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u += spancount;
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// calculate 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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D_Sky_uv_To_st (u, v, &snext, &tnext);
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sstep = (snext - s) >> SKY_SPAN_SHIFT;
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tstep = (tnext - t) >> SKY_SPAN_SHIFT;
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} else {
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// calculate s and t at last pixel in span,
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// calculate s and t steps across span by division
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spancountminus1 = (float) (spancount - 1);
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if (spancountminus1 > 0) {
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u += spancountminus1;
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D_Sky_uv_To_st (u, v, &snext, &tnext);
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sstep = (snext - s) / spancountminus1;
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tstep = (tnext - t) / spancountminus1;
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}
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}
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do {
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*pdest++ = r_skysource[((t & R_SKY_TMASK) >> 8) +
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((s & R_SKY_SMASK) >> 16)];
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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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} while ((pspan = pspan->pnext) != NULL);
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}
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