src/rt/ambient.c

/* Copyright (c) 1991 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  ambient.c - routines dealing with ambient (inter-reflected) component.
 *
 *  The macro AMBFLUSH (if defined) is the number of ambient values
 *      to wait before flushing to the ambient file.
 *
 *     5/9/86
 */

#include  "ray.h"

#include  "octree.h"

#include  "otypes.h"

#include  "ambient.h"

#include  "random.h"

#define  OCTSCALE       0.5     /* ceil((valid rad.)/(cube size)) */

typedef struct ambtree {
        AMBVAL  *alist;         /* ambient value list */
        struct ambtree  *kid;   /* 8 child nodes */
}  AMBTREE;                     /* ambient octree */

extern CUBE  thescene;          /* contains space boundaries */

#define  MAXASET        511     /* maximum number of elements in ambient set */
OBJECT  ambset[MAXASET+1]={0};  /* ambient include/exclude set */

double  maxarad;                /* maximum ambient radius */
double  minarad;                /* minimum ambient radius */

static AMBTREE  atrunk;         /* our ambient trunk node */

static FILE  *ambfp = NULL;     /* ambient file pointer */

#define  newambval()    (AMBVAL *)bmalloc(sizeof(AMBVAL))

#define  newambtree()   (AMBTREE *)calloc(8, sizeof(AMBTREE))


setambient(afile)                       /* initialize calculation */
char  *afile;
{
        long  ftell();
        AMBVAL  amb;

        maxarad = thescene.cusize / 2.0;                /* maximum radius */
                                                        /* minimum radius */
        minarad = ambres > 0 ? thescene.cusize/ambres : 0.0;

                                        /* open ambient file */
        if (afile != NULL)
                if ((ambfp = fopen(afile, "r+")) != NULL) {
                        while (fread((char *)&amb,sizeof(AMBVAL),1,ambfp) == 1)
                                avinsert(&amb, &atrunk, thescene.cuorg,
                                                thescene.cusize);
                                                        /* align */
                        fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1);
                } else if ((ambfp = fopen(afile, "w")) == NULL) {
                        sprintf(errmsg, "cannot open ambient file \"%s\"",
                                        afile);
                        error(SYSTEM, errmsg);
                }
}


ambnotify(obj)                  /* record new modifier */
OBJECT  obj;
{
        static int  hitlimit = 0;
        register OBJREC  *o = objptr(obj);
        register char  **amblp;

        if (hitlimit || !ismodifier(o->otype))
                return;
        for (amblp = amblist; *amblp != NULL; amblp++)
                if (!strcmp(o->oname, *amblp)) {
                        if (ambset[0] >= MAXASET) {
                                error(WARNING, "too many modifiers in ambient list");
                                hitlimit++;
                                return;         /* should this be fatal? */
                        }
                        insertelem(ambset, obj);
                        return;
                }
}


ambient(acol, r)                /* compute ambient component for ray */
COLOR  acol;
register RAY  *r;
{
        static int  rdepth = 0;                 /* ambient recursion */
        double  wsum;

        rdepth++;                               /* increment level */

        if (ambdiv <= 0)                        /* no ambient calculation */
                goto dumbamb;
                                                /* check number of bounces */
        if (rdepth > ambounce)
                goto dumbamb;
                                                /* check ambient list */
        if (ambincl != -1 && r->ro != NULL &&
                        ambincl != inset(ambset, r->ro->omod))
                goto dumbamb;

        if (ambacc <= FTINY) {                  /* no ambient storage */
                if (doambient(acol, r, NULL, NULL) == 0.0)
                        goto dumbamb;
                goto done;
        }
                                                /* get ambient value */
        setcolor(acol, 0.0, 0.0, 0.0);
        wsum = sumambient(acol, r, &atrunk, thescene.cuorg, thescene.cusize);
        if (wsum > FTINY)
                scalecolor(acol, 1.0/wsum);
        else if (makeambient(acol, r) == 0.0)
                goto dumbamb;
        goto done;

dumbamb:                                        /* return global value */
        copycolor(acol, ambval);
done:                                           /* must finish here! */
        rdepth--;
}


double
sumambient(acol, r, at, c0, s)          /* get interpolated ambient value */
COLOR  acol;
register RAY  *r;
AMBTREE  *at;
FVECT  c0;
double  s;
{
        extern double  sqrt();
        double  d, e1, e2, wt, wsum;
        COLOR  ct;
        FVECT  ck0;
        int  i;
        register int  j;
        register AMBVAL  *av;
                                        /* do this node */
        wsum = 0.0;
        for (av = at->alist; av != NULL; av = av->next) {
                /*
                 *  Ray strength test.
                 */
                if (av->lvl > r->rlvl || av->weight < r->rweight-FTINY)
                        continue;
                /*
                 *  Ambient radius test.
                 */
                e1 = 0.0;
                for (j = 0; j < 3; j++) {
                        d = av->pos[j] - r->rop[j];
                        e1 += d * d;
                }
                e1 /= av->rad * av->rad;
                if (e1 > ambacc*ambacc*1.21)
                        continue;
                /*
                 *  Normal direction test.
                 */
                e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
                if (e2 < 0.0) e2 = 0.0;
                if (e1 + e2 > ambacc*ambacc*1.21)
                        continue;
                /*
                 *  Ray behind test.
                 */
                d = 0.0;
                for (j = 0; j < 3; j++)
                        d += (r->rop[j] - av->pos[j]) *
                                        (av->dir[j] + r->ron[j]);
                if (d*0.5 < -minarad*ambacc)
                        continue;
                /*
                 *  Jittering final test reduces image artifacts.
                 */
                wt = sqrt(e1) + sqrt(e2);
                wt *= .9 + .2*frandom();
                if (wt > ambacc)
                        continue;
                if (wt <= 1e-3)
                        wt = 1e3;
                else
                        wt = 1.0 / wt;
                wsum += wt;
                copycolor(ct, av->val);
                scalecolor(ct, wt);
                addcolor(acol, ct);
        }
        if (at->kid == NULL)
                return(wsum);
                                        /* do children */
        s *= 0.5;
        for (i = 0; i < 8; i++) {
                for (j = 0; j < 3; j++) {
                        ck0[j] = c0[j];
                        if (1<<j & i)
                                ck0[j] += s;
                        if (r->rop[j] < ck0[j] - OCTSCALE*s)
                                break;
                        if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
                                break;
                }
                if (j == 3)
                        wsum += sumambient(acol, r, at->kid+i, ck0, s);
        }
        return(wsum);
}


double
makeambient(acol, r)            /* make a new ambient value */
COLOR  acol;
register RAY  *r;
{
        AMBVAL  amb;
        FVECT   gp, gd;

        amb.rad = doambient(acol, r, gp, gd);   /* compute ambient */
        if (amb.rad == 0.0)
                return(0.0);
                                                /* store it */
        VCOPY(amb.pos, r->rop);
        VCOPY(amb.dir, r->ron);
        amb.lvl = r->rlvl;
        amb.weight = r->rweight;
        copycolor(amb.val, acol);
        VCOPY(amb.gpos, gp);
        VCOPY(amb.gdir, gd);
                                                /* insert into tree */
        avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize);
        avsave(&amb);                           /* write to file */
        return(amb.rad);
}


static
avsave(av)                              /* save an ambient value */
AMBVAL  *av;
{
#ifdef  AMBFLUSH
        static int  nunflshed = 0;
#endif
        if (ambfp == NULL)
                return;
        if (fwrite((char *)av, sizeof(AMBVAL), 1, ambfp) != 1)
                goto writerr;
#ifdef  AMBFLUSH
        if (++nunflshed >= AMBFLUSH) {
                if (fflush(ambfp) == EOF)
                        goto writerr;
                nunflshed = 0;
        }
#endif
        return;
writerr:
        error(SYSTEM, "error writing ambient file");
}


static
avinsert(aval, at, c0, s)               /* insert ambient value in a tree */
AMBVAL  *aval;
register AMBTREE  *at;
FVECT  c0;
double  s;
{
        FVECT  ck0;
        int  branch;
        register AMBVAL  *av;
        register int  i;

        if ((av = newambval()) == NULL)
                goto memerr;
        copystruct(av, aval);
        VCOPY(ck0, c0);
        while (s*(OCTSCALE/2) > av->rad*ambacc) {
                if (at->kid == NULL)
                        if ((at->kid = newambtree()) == NULL)
                                goto memerr;
                s *= 0.5;
                branch = 0;
                for (i = 0; i < 3; i++)
                        if (av->pos[i] > ck0[i] + s) {
                                ck0[i] += s;
                                branch |= 1 << i;
                        }
                at = at->kid + branch;
        }
        av->next = at->alist;
        at->alist = av;
        return;
memerr:
        error(SYSTEM, "out of memory in avinsert");
}
Revision:	1.14
Committed:	Fri Jun 7 10:04:29 1991 UTC (32 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.13:	+13 -225 lines
Log Message:	created ambient.h and ambcomp.c files
#	User	Rev	Content
1	greg	1.14	/* Copyright (c) 1991 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* ambient.c - routines dealing with ambient (inter-reflected) component.
9			*
10			* The macro AMBFLUSH (if defined) is the number of ambient values
11			* to wait before flushing to the ambient file.
12			*
13			* 5/9/86
14			*/
15
16			#include "ray.h"
17
18			#include "octree.h"
19
20	greg	1.8	#include "otypes.h"
21
22	greg	1.14	#include "ambient.h"
23
24	greg	1.1	#include "random.h"
25
26			#define OCTSCALE 0.5 /* ceil((valid rad.)/(cube size)) */
27
28	greg	1.14	typedef struct ambtree {
29			AMBVAL alist; / ambient value list */
30			struct ambtree kid; / 8 child nodes */
31			} AMBTREE; /* ambient octree */
32
33	greg	1.1	extern CUBE thescene; /* contains space boundaries */
34
35	greg	1.11	#define MAXASET 511 /* maximum number of elements in ambient set */
36			OBJECT ambset[MAXASET+1]={0}; /* ambient include/exclude set */
37	greg	1.1
38			double maxarad; /* maximum ambient radius */
39			double minarad; /* minimum ambient radius */
40
41			static AMBTREE atrunk; /* our ambient trunk node */
42
43			static FILE ambfp = NULL; / ambient file pointer */
44
45			#define newambval() (AMBVAL *)bmalloc(sizeof(AMBVAL))
46
47			#define newambtree() (AMBTREE *)calloc(8, sizeof(AMBTREE))
48
49
50			setambient(afile) /* initialize calculation */
51			char *afile;
52			{
53			long ftell();
54			AMBVAL amb;
55	greg	1.8
56	greg	1.1	maxarad = thescene.cusize / 2.0; /* maximum radius */
57			/* minimum radius */
58			minarad = ambres > 0 ? thescene.cusize/ambres : 0.0;
59
60			/* open ambient file */
61			if (afile != NULL)
62			if ((ambfp = fopen(afile, "r+")) != NULL) {
63	greg	1.9	while (fread((char *)&amb,sizeof(AMBVAL),1,ambfp) == 1)
64	greg	1.1	avinsert(&amb, &atrunk, thescene.cuorg,
65			thescene.cusize);
66			/* align */
67			fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1);
68			} else if ((ambfp = fopen(afile, "w")) == NULL) {
69			sprintf(errmsg, "cannot open ambient file \"%s\"",
70			afile);
71			error(SYSTEM, errmsg);
72	greg	1.8	}
73			}
74
75
76			ambnotify(obj) /* record new modifier */
77			OBJECT obj;
78			{
79	greg	1.11	static int hitlimit = 0;
80	greg	1.8	register OBJREC *o = objptr(obj);
81			register char **amblp;
82
83	greg	1.11	if (hitlimit \|\| !ismodifier(o->otype))
84	greg	1.8	return;
85			for (amblp = amblist; *amblp != NULL; amblp++)
86			if (!strcmp(o->oname, *amblp)) {
87	greg	1.11	if (ambset[0] >= MAXASET) {
88			error(WARNING, "too many modifiers in ambient list");
89			hitlimit++;
90			return; /* should this be fatal? */
91			}
92	greg	1.8	insertelem(ambset, obj);
93			return;
94	greg	1.1	}
95			}
96
97
98			ambient(acol, r) /* compute ambient component for ray */
99			COLOR acol;
100			register RAY *r;
101			{
102			static int rdepth = 0; /* ambient recursion */
103			double wsum;
104
105			rdepth++; /* increment level */
106
107			if (ambdiv <= 0) /* no ambient calculation */
108			goto dumbamb;
109			/* check number of bounces */
110			if (rdepth > ambounce)
111			goto dumbamb;
112			/* check ambient list */
113			if (ambincl != -1 && r->ro != NULL &&
114			ambincl != inset(ambset, r->ro->omod))
115			goto dumbamb;
116
117			if (ambacc <= FTINY) { /* no ambient storage */
118	greg	1.14	if (doambient(acol, r, NULL, NULL) == 0.0)
119	greg	1.1	goto dumbamb;
120			goto done;
121			}
122			/* get ambient value */
123			setcolor(acol, 0.0, 0.0, 0.0);
124			wsum = sumambient(acol, r, &atrunk, thescene.cuorg, thescene.cusize);
125			if (wsum > FTINY)
126			scalecolor(acol, 1.0/wsum);
127			else if (makeambient(acol, r) == 0.0)
128			goto dumbamb;
129			goto done;
130
131			dumbamb: /* return global value */
132			copycolor(acol, ambval);
133			done: /* must finish here! */
134			rdepth--;
135			}
136
137
138			double
139			sumambient(acol, r, at, c0, s) /* get interpolated ambient value */
140			COLOR acol;
141			register RAY *r;
142			AMBTREE *at;
143			FVECT c0;
144			double s;
145			{
146			extern double sqrt();
147			double d, e1, e2, wt, wsum;
148			COLOR ct;
149			FVECT ck0;
150			int i;
151			register int j;
152			register AMBVAL *av;
153	greg	1.7	/* do this node */
154	greg	1.1	wsum = 0.0;
155			for (av = at->alist; av != NULL; av = av->next) {
156			/*
157			* Ray strength test.
158			*/
159			if (av->lvl > r->rlvl \|\| av->weight < r->rweight-FTINY)
160			continue;
161			/*
162			* Ambient radius test.
163			*/
164			e1 = 0.0;
165			for (j = 0; j < 3; j++) {
166			d = av->pos[j] - r->rop[j];
167			e1 += d * d;
168			}
169			e1 /= av->rad * av->rad;
170			if (e1 > ambaccambacc1.21)
171			continue;
172			/*
173			* Normal direction test.
174			*/
175			e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
176			if (e2 < 0.0) e2 = 0.0;
177			if (e1 + e2 > ambaccambacc1.21)
178			continue;
179			/*
180			* Ray behind test.
181			*/
182			d = 0.0;
183			for (j = 0; j < 3; j++)
184			d += (r->rop[j] - av->pos[j]) *
185			(av->dir[j] + r->ron[j]);
186	greg	1.13	if (d0.5 < -minaradambacc)
187	greg	1.1	continue;
188			/*
189			* Jittering final test reduces image artifacts.
190			*/
191			wt = sqrt(e1) + sqrt(e2);
192	greg	1.7	wt = .9 + .2frandom();
193	greg	1.6	if (wt > ambacc)
194	greg	1.1	continue;
195			if (wt <= 1e-3)
196			wt = 1e3;
197			else
198			wt = 1.0 / wt;
199			wsum += wt;
200			copycolor(ct, av->val);
201			scalecolor(ct, wt);
202			addcolor(acol, ct);
203	greg	1.7	}
204			if (at->kid == NULL)
205			return(wsum);
206			/* do children */
207			s *= 0.5;
208			for (i = 0; i < 8; i++) {
209			for (j = 0; j < 3; j++) {
210			ck0[j] = c0[j];
211			if (1<<j & i)
212			ck0[j] += s;
213			if (r->rop[j] < ck0[j] - OCTSCALE*s)
214			break;
215			if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
216			break;
217			}
218			if (j == 3)
219			wsum += sumambient(acol, r, at->kid+i, ck0, s);
220	greg	1.1	}
221			return(wsum);
222			}
223
224
225			double
226			makeambient(acol, r) /* make a new ambient value */
227			COLOR acol;
228			register RAY *r;
229			{
230			AMBVAL amb;
231	greg	1.14	FVECT gp, gd;
232	greg	1.1
233	greg	1.14	amb.rad = doambient(acol, r, gp, gd); /* compute ambient */
234	greg	1.1	if (amb.rad == 0.0)
235			return(0.0);
236			/* store it */
237			VCOPY(amb.pos, r->rop);
238			VCOPY(amb.dir, r->ron);
239			amb.lvl = r->rlvl;
240			amb.weight = r->rweight;
241			copycolor(amb.val, acol);
242	greg	1.14	VCOPY(amb.gpos, gp);
243			VCOPY(amb.gdir, gd);
244	greg	1.1	/* insert into tree */
245			avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize);
246			avsave(&amb); /* write to file */
247			return(amb.rad);
248			}
249
250
251			static
252			avsave(av) /* save an ambient value */
253			AMBVAL *av;
254			{
255			#ifdef AMBFLUSH
256			static int nunflshed = 0;
257			#endif
258			if (ambfp == NULL)
259			return;
260	greg	1.9	if (fwrite((char *)av, sizeof(AMBVAL), 1, ambfp) != 1)
261	greg	1.1	goto writerr;
262			#ifdef AMBFLUSH
263			if (++nunflshed >= AMBFLUSH) {
264			if (fflush(ambfp) == EOF)
265			goto writerr;
266			nunflshed = 0;
267			}
268			#endif
269			return;
270			writerr:
271			error(SYSTEM, "error writing ambient file");
272			}
273
274
275			static
276			avinsert(aval, at, c0, s) /* insert ambient value in a tree */
277			AMBVAL *aval;
278			register AMBTREE *at;
279			FVECT c0;
280			double s;
281			{
282			FVECT ck0;
283			int branch;
284			register AMBVAL *av;
285			register int i;
286
287			if ((av = newambval()) == NULL)
288			goto memerr;
289	greg	1.9	copystruct(av, aval);
290	greg	1.1	VCOPY(ck0, c0);
291			while (s(OCTSCALE/2) > av->radambacc) {
292			if (at->kid == NULL)
293			if ((at->kid = newambtree()) == NULL)
294			goto memerr;
295			s *= 0.5;
296			branch = 0;
297			for (i = 0; i < 3; i++)
298			if (av->pos[i] > ck0[i] + s) {
299			ck0[i] += s;
300			branch \|= 1 << i;
301			}
302			at = at->kid + branch;
303			}
304			av->next = at->alist;
305			at->alist = av;
306			return;
307			memerr:
308			error(SYSTEM, "out of memory in avinsert");
309			}