/*
d_sky.c
(description)
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
$Id: d_sky.c,v 1.1.1.1 2001/03/06 09:33:10 lordhavoc Exp $
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "d_local.h"
#include "r_local.h"
#include "sys.h"
#include "vid.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_DrawSkyScans
*/
void
D_DrawSkyScans (espan_t *pspan)
{
switch(r_pixbytes)
{
case 1:
{
int count, spancount, u, v;
byte *pdest;
fixed16_t s, t, snext, tnext, sstep, tstep;
int spancountminus1;
sstep = 0; // keep compiler happy
tstep = 0; // ditto
do {
pdest = (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++ = ((byte *)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) != NULL);
}
break;
case 2:
{
int count, spancount, u, v;
short *pdest;
fixed16_t s, t, snext, tnext, sstep, tstep;
int spancountminus1;
sstep = 0; // keep compiler happy
tstep = 0; // ditto
do {
pdest = (short *) 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++ = ((short *)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) != NULL);
}
break;
case 4:
{
int count, spancount, u, v;
int *pdest;
fixed16_t s, t, snext, tnext, sstep, tstep;
int spancountminus1;
sstep = 0; // keep compiler happy
tstep = 0; // ditto
do {
pdest = (int *) 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++ = ((int *)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) != NULL);
}
break;
default:
Sys_Error("D_DrawSkyScans: unsupported r_pixbytes %i\n", r_pixbytes);
}
}