1/* 2Copyright (C) 1996-1997 Id Software, Inc. 3 4This program is free software; you can redistribute it and/or 5modify it under the terms of the GNU General Public License 6as published by the Free Software Foundation; either version 2 7of the License, or (at your option) any later version. 8 9This program is distributed in the hope that it will be useful, 10but WITHOUT ANY WARRANTY; without even the implied warranty of 11MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 13See the GNU General Public License for more details. 14 15You should have received a copy of the GNU General Public License 16along with this program; if not, write to the Free Software 17Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 18 19*/ 20// d_sky.c 21 22#include "quakedef.h" 23#include "r_local.h" 24#include "d_local.h" 25 26#define SKY_SPAN_SHIFT 5 27#define SKY_SPAN_MAX (1 << SKY_SPAN_SHIFT) 28 29 30/* 31================= 32D_Sky_uv_To_st 33================= 34*/ 35void D_Sky_uv_To_st (int u, int v, fixed16_t *s, fixed16_t *t) 36{ 37 float wu, wv, temp; 38 vec3_t end; 39 40 if (r_refdef.vrect.width >= r_refdef.vrect.height) 41 temp = (float)r_refdef.vrect.width; 42 else 43 temp = (float)r_refdef.vrect.height; 44 45 wu = 8192.0 * (float)(u-((int)vid.width>>1)) / temp; 46 wv = 8192.0 * (float)(((int)vid.height>>1)-v) / temp; 47 48 end[0] = 4096*vpn[0] + wu*vright[0] + wv*vup[0]; 49 end[1] = 4096*vpn[1] + wu*vright[1] + wv*vup[1]; 50 end[2] = 4096*vpn[2] + wu*vright[2] + wv*vup[2]; 51 end[2] *= 3; 52 VectorNormalize (end); 53 54 temp = skytime*skyspeed; // TODO: add D_SetupFrame & set this there 55 *s = (int)((temp + 6*(SKYSIZE/2-1)*end[0]) * 0x10000); 56 *t = (int)((temp + 6*(SKYSIZE/2-1)*end[1]) * 0x10000); 57} 58 59 60/* 61================= 62D_DrawSkyScans8 63================= 64*/ 65void D_DrawSkyScans8 (espan_t *pspan) 66{ 67 int count, spancount, u, v; 68 unsigned char *pdest; 69 fixed16_t s, t, snext, tnext, sstep, tstep; 70 int spancountminus1; 71 72 sstep = 0; // keep compiler happy 73 tstep = 0; // ditto 74 75 do 76 { 77 pdest = (unsigned char *)((byte *)d_viewbuffer + 78 (screenwidth * pspan->v) + pspan->u); 79 80 count = pspan->count; 81 82 // calculate the initial s & t 83 u = pspan->u; 84 v = pspan->v; 85 D_Sky_uv_To_st (u, v, &s, &t); 86 87 do 88 { 89 if (count >= SKY_SPAN_MAX) 90 spancount = SKY_SPAN_MAX; 91 else 92 spancount = count; 93 94 count -= spancount; 95 96 if (count) 97 { 98 u += spancount; 99 100 // calculate s and t at far end of span, 101 // calculate s and t steps across span by shifting 102 D_Sky_uv_To_st (u, v, &snext, &tnext); 103 104 sstep = (snext - s) >> SKY_SPAN_SHIFT; 105 tstep = (tnext - t) >> SKY_SPAN_SHIFT; 106 } 107 else 108 { 109 // calculate s and t at last pixel in span, 110 // calculate s and t steps across span by division 111 spancountminus1 = (float)(spancount - 1); 112 113 if (spancountminus1 > 0) 114 { 115 u += spancountminus1; 116 D_Sky_uv_To_st (u, v, &snext, &tnext); 117 118 sstep = (snext - s) / spancountminus1; 119 tstep = (tnext - t) / spancountminus1; 120 } 121 } 122 123 do 124 { 125 *pdest++ = r_skysource[((t & R_SKY_TMASK) >> 8) + 126 ((s & R_SKY_SMASK) >> 16)]; 127 s += sstep; 128 t += tstep; 129 } while (--spancount > 0); 130 131 s = snext; 132 t = tnext; 133 134 } while (count > 0); 135 136 } while ((pspan = pspan->pnext) != NULL); 137} 138 139