ref: 376e27387ce41157c13401981ecab105612c244e
dir: /d_sky.c/
#include <u.h> #include <libc.h> #include "dat.h" #include "quakedef.h" #include "fns.h" #define SKY_SPAN_SHIFT 5 #define SKY_SPAN_MAX (1 << SKY_SPAN_SHIFT) /* ================= D_Sky_uv_To_st ================= */ void D_Sky_uv_To_st (int u, int v, fixed16_t *s, fixed16_t *t) { float wu, wv, temp; vec3_t end; if (r_refdef.vrect.width >= r_refdef.vrect.height) temp = (float)r_refdef.vrect.width; else temp = (float)r_refdef.vrect.height; wu = 8192.0 * (float)(u-((int)vid.width>>1)) / temp; wv = 8192.0 * (float)(((int)vid.height>>1)-v) / temp; end[0] = 4096*vpn[0] + wu*vright[0] + wv*vup[0]; end[1] = 4096*vpn[1] + wu*vright[1] + wv*vup[1]; end[2] = 4096*vpn[2] + wu*vright[2] + wv*vup[2]; end[2] *= 3; VectorNormalize (end); temp = skytime*skyspeed; // TODO: add D_SetupFrame & set this there *s = (int)((temp + 6*(SKYSIZE/2-1)*end[0]) * 0x10000); *t = (int)((temp + 6*(SKYSIZE/2-1)*end[1]) * 0x10000); } /* ================= D_DrawSkyScans8 ================= */ void D_DrawSkyScans8 (espan_t *pspan) { int count, spancount, u, v; unsigned char *pdest; fixed16_t s, t, snext, tnext, sstep, tstep; int spancountminus1; sstep = 0; // keep compiler happy tstep = 0; // ditto do { pdest = (unsigned char *)((byte *)d_viewbuffer + (screenwidth * pspan->v) + pspan->u); count = pspan->count; // calculate the initial s & t u = pspan->u; v = pspan->v; D_Sky_uv_To_st (u, v, &s, &t); do { if (count >= SKY_SPAN_MAX) spancount = SKY_SPAN_MAX; else spancount = count; count -= spancount; if (count) { u += spancount; // calculate s and t at far end of span, // calculate s and t steps across span by shifting D_Sky_uv_To_st (u, v, &snext, &tnext); sstep = (snext - s) >> SKY_SPAN_SHIFT; tstep = (tnext - t) >> SKY_SPAN_SHIFT; } else { // calculate s and t at last pixel in span, // calculate s and t steps across span by division spancountminus1 = (float)(spancount - 1); if (spancountminus1 > 0) { u += spancountminus1; D_Sky_uv_To_st (u, v, &snext, &tnext); sstep = (snext - s) / spancountminus1; tstep = (tnext - t) / spancountminus1; } } do { *pdest++ = r_skysource[((t & R_SKY_TMASK) >> 8) + ((s & R_SKY_SMASK) >> 16)]; s += sstep; t += tstep; } while (--spancount > 0); s = snext; t = tnext; } while (count > 0); } while ((pspan = pspan->pnext) != nil); }