src/util/glareval.c

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

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

/*
 * Compute pixels for glare calculation
 */

#include "glare.h"
#include "resolu.h"
                                        /* maximum rtrace buffer size */
#define MAXPIX          (4096/(6*sizeof(float)))

#define MAXSBUF         786432  /* maximum total size of scanline buffer */
#define HSIZE           317     /* size of scanline hash table */
#define NRETIRE         16      /* number of scanlines to retire at once */

int     rt_pd[3] = {-1,-1,-1};  /* process id & descriptors for rtrace */

FILE    *pictfp = NULL;         /* picture file pointer */
double  exposure;               /* picture exposure */
int     pxsiz, pysiz;           /* picture dimensions */

static int      curpos;         /* current scanline */
static long     *scanpos;       /* scanline positions */

typedef struct scan {
        int     y;              /* scanline position */
        long    lused;          /* for LRU replacement */
        struct scan     *next;  /* next in this hash or free list */
        /* followed by the scanline data */
} SCAN;                 /* buffered scanline */

#define scandata(sl)    ((COLR *)((sl)+1))
#define shash(y)        ((y)%HSIZE)

static int      maxpix;         /* maximum number of pixels to buffer */

static SCAN     *freelist;              /* scanline free list */
static SCAN     *hashtab[HSIZE];        /* scanline hash table */

static long     ncall = 0L;     /* number of calls to getpictscan */
static long     nread = 0L;     /* number of scanlines read */
static long     nrecl = 0L;     /* number of scanlines reclaimed */

static int      wrongformat = 0;

SCAN    *scanretire();

extern long     ftell();


SCAN *
claimscan(y)                    /* claim scanline from buffers */
int     y;
{
        int     hi = shash(y);
        SCAN    *slast;
        register SCAN   *sl;

        for (sl = hashtab[hi]; sl != NULL; sl = sl->next)
                if (sl->y == y)                         /* active scanline */
                        return(sl);
        for (slast = NULL, sl = freelist; sl != NULL; slast = sl, sl = sl->next)
                if (sl->y == -1 || sl->y == y || sl->next == NULL) {
                        if (slast == NULL)              /* remove from free */
                                freelist = sl->next;
                        else
                                slast->next = sl->next;
                        if (sl->y == y) {               /* reclaim */
                                sl->next = hashtab[hi];
                                hashtab[hi] = sl;
                                nrecl++;
                        }
                        return(sl);
                }
        return(scanretire());           /* need more free scanlines */
}


COLR *
getpictscan(y)                  /* get picture scanline */
int     y;
{
        register SCAN   *sl;
        register int    i;
                                        /* first check our buffers */
        sl = claimscan(y);
        if (sl == NULL)
                memerr("claimscan()");
        sl->lused = ncall++;
        if (sl->y == y)                 /* scan hit */
                return(scandata(sl));
                                        /* else read in replacement */
        if (scanpos[y] < 0) {                   /* need to search */
                for (i = y+1; i < curpos; i++)
                        if (scanpos[i] >= 0) {
                                if (fseek(pictfp, scanpos[i], 0) < 0)
                                        goto seekerr;
                                curpos = i;
                                break;
                        }
                while (curpos >= y) {
                        scanpos[curpos] = ftell(pictfp);
                        if (freadcolrs(scandata(sl), pxsiz, pictfp) < 0)
                                goto readerr;
                        nread++;
                        curpos--;
                }
        } else {
                if (curpos != y && fseek(pictfp, scanpos[y], 0) < 0)
                        goto seekerr;
                if (freadcolrs(scandata(sl), pxsiz, pictfp) < 0)
                        goto readerr;
                nread++;
                curpos = y-1;
        }
        sl->y = y;
        i = shash(y);                   /* add to hash list */
        sl->next = hashtab[i];
        hashtab[i] = sl;
        return(scandata(sl));
readerr:
        fprintf(stderr, "%s: picture read error\n", progname);
        exit(1);
seekerr:
        fprintf(stderr, "%s: picture seek error\n", progname);
        exit(1);
}


#ifdef DEBUG
pict_stats()                    /* print out picture read statistics */
{
        static long     lastcall = 0L;  /* ncall at last report */
        static long     lastread = 0L;  /* nread at last report */
        static long     lastrecl = 0L;  /* nrecl at last report */

        if (ncall == lastcall)
                return;
        fprintf(stderr, "%s: %ld scanlines read (%ld reclaimed) in %ld calls\n",
                progname, nread-lastread, nrecl-lastrecl, ncall-lastcall);
        lastcall = ncall;
        lastread = nread;
        lastrecl = nrecl;
}
#endif


double
pict_val(vd)                    /* find picture value for view direction */
FVECT   vd;
{
        FVECT   pp;
        FVECT   ip;
        COLOR   res;

        if (pictfp == NULL)
                return(-1.0);
        pp[0] = pictview.vp[0] + vd[0];
        pp[1] = pictview.vp[1] + vd[1];
        pp[2] = pictview.vp[2] + vd[2];
        viewloc(ip, &pictview, pp);
        if (ip[2] <= FTINY || ip[0] < 0. || ip[0] >= 1. ||
                        ip[1] < 0. || ip[1] >= 1.)
                return(-1.0);
        colr_color(res, getpictscan((int)(ip[1]*pysiz))[(int)(ip[0]*pxsiz)]);
        return(luminance(res)/exposure);
}


double
getviewpix(vh, vv)              /* compute single view pixel */
int     vh, vv;
{
        FVECT   dir;
        float   rt_buf[12];
        double  res;

        if (compdir(dir, vh, vv) < 0)
                return(-1.0);
        npixinvw++;
        if ((res = pict_val(dir)) >= 0.0)
                return(res);
        if (rt_pd[0] == -1) {
                npixmiss++;
                return(-1.0);
        }
        rt_buf[0] = ourview.vp[0];
        rt_buf[1] = ourview.vp[1];
        rt_buf[2] = ourview.vp[2];
        rt_buf[3] = dir[0];
        rt_buf[4] = dir[1];
        rt_buf[5] = dir[2];
        rt_compute(rt_buf, 1);
        return(luminance(rt_buf));
}


getviewspan(vv, vb)             /* compute a span of view pixels */
int     vv;
float   *vb;
{
        float   rt_buf[6*MAXPIX];       /* rtrace send/receive buffer */
        register int    n;              /* number of pixels in buffer */
        short   buf_vh[MAXPIX];         /* pixel positions */
        FVECT   dir;
        register int    vh;

#ifdef DEBUG
        if (verbose)
                fprintf(stderr, "%s: computing view span at %d...\n",
                                progname, vv);
#endif
        n = 0;
        for (vh = -hsize; vh <= hsize; vh++) {
                if (compdir(dir, vh, vv) < 0) {         /* not in view */
                        vb[vh+hsize] = -1.0;
                        continue;
                }
                npixinvw++;
                if ((vb[vh+hsize] = pict_val(dir)) >= 0.0)
                        continue;
                if (rt_pd[0] == -1) {           /* missing information */
                        npixmiss++;
                        continue;
                }
                                                /* send to rtrace */
                if (n >= maxpix) {                      /* flush */
                        rt_compute(rt_buf, n);
                        while (n-- > 0)
                                vb[buf_vh[n]+hsize] = luminance(rt_buf+3*n);
                }
                rt_buf[6*n] = ourview.vp[0];
                rt_buf[6*n+1] = ourview.vp[1];
                rt_buf[6*n+2] = ourview.vp[2];
                rt_buf[6*n+3] = dir[0];
                rt_buf[6*n+4] = dir[1];
                rt_buf[6*n+5] = dir[2];
                buf_vh[n++] = vh;
        }
#ifdef DEBUG
        if (verbose)
                pict_stats();
#endif
        if (n > 0) {                            /* process pending buffer */
                rt_compute(rt_buf, n);
                while (n-- > 0)
                        vb[buf_vh[n]+hsize] = luminance(rt_buf+3*n);
        }
}


rt_compute(pb, np)              /* process buffer through rtrace */
float   *pb;
int     np;
{
#ifdef DEBUG
        if (verbose && np > 1)
                fprintf(stderr, "%s: sending %d samples to rtrace...\n",
                                progname, np);
#endif
        bzero(pb+6*np, 6*sizeof(float));
        if (process(rt_pd, pb, pb, 3*sizeof(float)*np,
                        6*sizeof(float)*(np+1)) < 3*sizeof(float)*np) {
                fprintf(stderr, "%s: rtrace communication error\n",
                                progname);
                exit(1);
        }
}


getexpos(s)                     /* get exposure from header line */
char    *s;
{
        char    fmt[32];

        if (isexpos(s))
                exposure *= exposval(s);
        else if (isformat(s)) {
                formatval(fmt, s);
                wrongformat = strcmp(fmt, COLRFMT);
        }
}


open_pict(fn)                   /* open picture file */
char    *fn;
{
        if ((pictfp = fopen(fn, "r")) == NULL) {
                fprintf("%s: cannot open\n", fn);
                exit(1);
        }
        exposure = 1.0;
        getheader(pictfp, getexpos, NULL);
        if (wrongformat || !fscnresolu(&pxsiz, &pysiz, pictfp)) {
                fprintf(stderr, "%s: incompatible picture format\n", fn);
                exit(1);
        }
        initscans();
}


close_pict()                    /* done with picture */
{
        if (pictfp == NULL)
                return;
        fclose(pictfp);
        donescans();
        pictfp = NULL;
}


fork_rtrace(av)                 /* open pipe and start rtrace */
char    *av[];
{
        int     rval;

        rval = open_process(rt_pd, av);
        if (rval < 0) {
                perror(progname);
                exit(1);
        }
        if (rval == 0) {
                fprintf(stderr, "%s: command not found\n", av[0]);
                exit(1);
        }
        maxpix = rval/(6*sizeof(float));
        if (maxpix > MAXPIX)
                maxpix = MAXPIX;
        maxpix--;
}


done_rtrace()                   /* wait for rtrace to finish */
{
        int     status;

        status = close_process(rt_pd);
        if (status > 0) {
                fprintf(stderr, "%s: bad status (%d) from rtrace\n",
                                progname, status);
                exit(1);
        }
        rt_pd[0] = -1;
}


SCAN *
scanretire()                    /* retire old scanlines to free list */
{
        SCAN    *sold[NRETIRE];
        int     n;
        int     h;
        register SCAN   *sl;
        register int    i;
                                        /* grab the NRETIRE oldest scanlines */
        sold[n = 0] = NULL;
        for (h = 0; h < HSIZE; h++)
                for (sl = hashtab[h]; sl != NULL; sl = sl->next) {
                        for (i = n; i && sold[i-1]->lused > sl->lused; i--)
                                if (i < NRETIRE)
                                        sold[i] = sold[i-1];
                        if (i < NRETIRE) {
                                sold[i] = sl;
                                if (n < NRETIRE)        /* grow list */
                                        n++;
                        }
                }
                                        /* put scanlines into free list */
        for (i = 0; i < n; i++) {
                h = shash(sold[i]->y);
                sl = hashtab[h];
                if (sl == sold[i])
                        hashtab[h] = sl->next;
                else {
                        while (sl->next != sold[i])     /* IS in list */
                                sl = sl->next;
                        sl->next = sold[i]->next;
                }
                if (i > 0) {            /* save oldest as return value */
                        sold[i]->next = freelist;
                        freelist = sold[i];
                }
        }
        return(sold[0]);
}


static char     *scan_buf;


initscans()                             /* initialize scanline buffers */
{
        int     scansize;
        register SCAN   *ptr;
        register int    i;
                                        /* initialize positions */
        scanpos = (long *)malloc(pysiz*sizeof(long));
        if (scanpos == NULL)
                memerr("scanline positions");
        for (i = pysiz-1; i >= 0; i--)
                scanpos[i] = -1L;
        curpos = pysiz-1;
                                        /* clear hash table */
        for (i = 0; i < HSIZE; i++)
                hashtab[i] = NULL;
                                        /* allocate scanline buffers */
        scansize = sizeof(SCAN) + pxsiz*sizeof(COLR);
#ifdef ALIGN
        scansize = scansize+(sizeof(ALIGN)-1) & ~(sizeof(ALIGN)-1);
#endif
        i = MAXSBUF / scansize;         /* compute number to allocate */
        if (i > HSIZE)
                i = HSIZE;
        scan_buf = malloc(i*scansize);  /* get in one big chunk */
        if (scan_buf == NULL)
                memerr("scanline buffers");
        ptr = (SCAN *)scan_buf;
        freelist = NULL;                /* build our free list */
        while (i-- > 0) {
                ptr->y = -1;
                ptr->lused = -1;
                ptr->next = freelist;
                freelist = ptr;
                ptr = (SCAN *)((char *)ptr + scansize); /* beware of C bugs */
        }
}


donescans()                             /* free up scanlines */
{
        free(scan_buf);
        free((char *)scanpos);
}
Revision:	1.21
Committed:	Mon Nov 11 15:09:42 1991 UTC (33 years, 11 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.20:	+8 -7 lines
Log Message:	changed call to viewpixel() -> viewloc()
#	User	Rev	Content
1	greg	1.1	/* Copyright (c) 1991 Regents of the University of California */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* Compute pixels for glare calculation
9			*/
10
11			#include "glare.h"
12	greg	1.21	#include "resolu.h"
13	greg	1.19	/* maximum rtrace buffer size */
14			#define MAXPIX (4096/(6*sizeof(float)))
15	greg	1.1
16	greg	1.16	#define MAXSBUF 786432 /* maximum total size of scanline buffer */
17	greg	1.9	#define HSIZE 317 /* size of scanline hash table */
18	greg	1.8	#define NRETIRE 16 /* number of scanlines to retire at once */
19	greg	1.1
20	greg	1.19	int rt_pd[3] = {-1,-1,-1}; /* process id & descriptors for rtrace */
21	greg	1.1
22			FILE pictfp = NULL; / picture file pointer */
23			double exposure; /* picture exposure */
24			int pxsiz, pysiz; /* picture dimensions */
25	greg	1.8
26			static int curpos; /* current scanline */
27			static long scanpos; / scanline positions */
28
29			typedef struct scan {
30			int y; /* scanline position */
31	greg	1.1	long lused; /* for LRU replacement */
32	greg	1.8	struct scan next; / next in this hash or free list */
33			/* followed by the scanline data */
34			} SCAN; /* buffered scanline */
35	greg	1.1
36	greg	1.8	#define scandata(sl) ((COLR *)((sl)+1))
37			#define shash(y) ((y)%HSIZE)
38
39	greg	1.19	static int maxpix; /* maximum number of pixels to buffer */
40
41	greg	1.8	static SCAN freelist; / scanline free list */
42			static SCAN hashtab[HSIZE]; / scanline hash table */
43
44	greg	1.2	static long ncall = 0L; /* number of calls to getpictscan */
45			static long nread = 0L; /* number of scanlines read */
46	greg	1.15	static long nrecl = 0L; /* number of scanlines reclaimed */
47	greg	1.1
48	greg	1.13	static int wrongformat = 0;
49
50	greg	1.8	SCAN *scanretire();
51
52	greg	1.5	extern long ftell();
53	greg	1.2
54	greg	1.5
55	greg	1.8	SCAN *
56			claimscan(y) /* claim scanline from buffers */
57			int y;
58			{
59			int hi = shash(y);
60			SCAN *slast;
61			register SCAN *sl;
62
63			for (sl = hashtab[hi]; sl != NULL; sl = sl->next)
64			if (sl->y == y) /* active scanline */
65			return(sl);
66			for (slast = NULL, sl = freelist; sl != NULL; slast = sl, sl = sl->next)
67			if (sl->y == -1 \|\| sl->y == y \|\| sl->next == NULL) {
68			if (slast == NULL) /* remove from free */
69			freelist = sl->next;
70			else
71			slast->next = sl->next;
72			if (sl->y == y) { /* reclaim */
73			sl->next = hashtab[hi];
74			hashtab[hi] = sl;
75	greg	1.15	nrecl++;
76	greg	1.8	}
77			return(sl);
78			}
79			return(scanretire()); /* need more free scanlines */
80			}
81
82
83	greg	1.1	COLR *
84			getpictscan(y) /* get picture scanline */
85			int y;
86			{
87	greg	1.8	register SCAN *sl;
88	greg	1.1	register int i;
89			/* first check our buffers */
90	greg	1.8	sl = claimscan(y);
91			if (sl == NULL)
92			memerr("claimscan()");
93			sl->lused = ncall++;
94			if (sl->y == y) /* scan hit */
95			return(scandata(sl));
96			/* else read in replacement */
97	greg	1.5	if (scanpos[y] < 0) { /* need to search */
98			for (i = y+1; i < curpos; i++)
99			if (scanpos[i] >= 0) {
100			if (fseek(pictfp, scanpos[i], 0) < 0)
101			goto seekerr;
102			curpos = i;
103			break;
104			}
105			while (curpos >= y) {
106	greg	1.1	scanpos[curpos] = ftell(pictfp);
107	greg	1.8	if (freadcolrs(scandata(sl), pxsiz, pictfp) < 0)
108	greg	1.1	goto readerr;
109	greg	1.5	nread++;
110	greg	1.1	curpos--;
111			}
112	greg	1.5	} else {
113			if (curpos != y && fseek(pictfp, scanpos[y], 0) < 0)
114			goto seekerr;
115	greg	1.8	if (freadcolrs(scandata(sl), pxsiz, pictfp) < 0)
116	greg	1.5	goto readerr;
117			nread++;
118			curpos = y-1;
119	greg	1.1	}
120	greg	1.8	sl->y = y;
121			i = shash(y); /* add to hash list */
122			sl->next = hashtab[i];
123			hashtab[i] = sl;
124			return(scandata(sl));
125	greg	1.1	readerr:
126			fprintf(stderr, "%s: picture read error\n", progname);
127			exit(1);
128	greg	1.5	seekerr:
129			fprintf(stderr, "%s: picture seek error\n", progname);
130			exit(1);
131	greg	1.1	}
132
133
134	greg	1.6	#ifdef DEBUG
135	greg	1.2	pict_stats() /* print out picture read statistics */
136			{
137			static long lastcall = 0L; /* ncall at last report */
138			static long lastread = 0L; /* nread at last report */
139	greg	1.15	static long lastrecl = 0L; /* nrecl at last report */
140	greg	1.2
141			if (ncall == lastcall)
142			return;
143	greg	1.15	fprintf(stderr, "%s: %ld scanlines read (%ld reclaimed) in %ld calls\n",
144			progname, nread-lastread, nrecl-lastrecl, ncall-lastcall);
145	greg	1.2	lastcall = ncall;
146			lastread = nread;
147	greg	1.15	lastrecl = nrecl;
148	greg	1.2	}
149	greg	1.6	#endif
150	greg	1.2
151
152	greg	1.1	double
153			pict_val(vd) /* find picture value for view direction */
154			FVECT vd;
155			{
156			FVECT pp;
157	greg	1.21	FVECT ip;
158	greg	1.1	COLOR res;
159
160			if (pictfp == NULL)
161			return(-1.0);
162			pp[0] = pictview.vp[0] + vd[0];
163			pp[1] = pictview.vp[1] + vd[1];
164			pp[2] = pictview.vp[2] + vd[2];
165	greg	1.21	viewloc(ip, &pictview, pp);
166			if (ip[2] <= FTINY \|\| ip[0] < 0. \|\| ip[0] >= 1. \|\|
167			ip[1] < 0. \|\| ip[1] >= 1.)
168	greg	1.1	return(-1.0);
169	greg	1.21	colr_color(res, getpictscan((int)(ip[1]pysiz))[(int)(ip[0]pxsiz)]);
170	greg	1.1	return(luminance(res)/exposure);
171			}
172
173
174			double
175	greg	1.14	getviewpix(vh, vv) /* compute single view pixel */
176	greg	1.1	int vh, vv;
177			{
178			FVECT dir;
179	greg	1.19	float rt_buf[12];
180	greg	1.1	double res;
181
182	greg	1.14	if (compdir(dir, vh, vv) < 0)
183	greg	1.1	return(-1.0);
184	greg	1.7	npixinvw++;
185	greg	1.1	if ((res = pict_val(dir)) >= 0.0)
186			return(res);
187	greg	1.19	if (rt_pd[0] == -1) {
188	greg	1.7	npixmiss++;
189	greg	1.1	return(-1.0);
190	greg	1.7	}
191	greg	1.1	rt_buf[0] = ourview.vp[0];
192			rt_buf[1] = ourview.vp[1];
193			rt_buf[2] = ourview.vp[2];
194			rt_buf[3] = dir[0];
195			rt_buf[4] = dir[1];
196			rt_buf[5] = dir[2];
197			rt_compute(rt_buf, 1);
198			return(luminance(rt_buf));
199			}
200
201
202			getviewspan(vv, vb) /* compute a span of view pixels */
203			int vv;
204			float *vb;
205			{
206			float rt_buf[6MAXPIX]; / rtrace send/receive buffer */
207	greg	1.3	register int n; /* number of pixels in buffer */
208	greg	1.1	short buf_vh[MAXPIX]; /* pixel positions */
209			FVECT dir;
210			register int vh;
211
212	greg	1.4	#ifdef DEBUG
213	greg	1.1	if (verbose)
214			fprintf(stderr, "%s: computing view span at %d...\n",
215			progname, vv);
216	greg	1.4	#endif
217	greg	1.3	n = 0;
218	greg	1.1	for (vh = -hsize; vh <= hsize; vh++) {
219	greg	1.14	if (compdir(dir, vh, vv) < 0) { /* not in view */
220	greg	1.1	vb[vh+hsize] = -1.0;
221			continue;
222			}
223	greg	1.7	npixinvw++;
224	greg	1.1	if ((vb[vh+hsize] = pict_val(dir)) >= 0.0)
225			continue;
226	greg	1.19	if (rt_pd[0] == -1) { /* missing information */
227	greg	1.7	npixmiss++;
228	greg	1.1	continue;
229	greg	1.7	}
230	greg	1.1	/* send to rtrace */
231	greg	1.19	if (n >= maxpix) { /* flush */
232	greg	1.3	rt_compute(rt_buf, n);
233			while (n-- > 0)
234			vb[buf_vh[n]+hsize] = luminance(rt_buf+3*n);
235	greg	1.1	}
236	greg	1.3	rt_buf[6*n] = ourview.vp[0];
237			rt_buf[6*n+1] = ourview.vp[1];
238			rt_buf[6*n+2] = ourview.vp[2];
239			rt_buf[6*n+3] = dir[0];
240			rt_buf[6*n+4] = dir[1];
241			rt_buf[6*n+5] = dir[2];
242			buf_vh[n++] = vh;
243	greg	1.1	}
244	greg	1.4	#ifdef DEBUG
245	greg	1.2	if (verbose)
246			pict_stats();
247	greg	1.4	#endif
248	greg	1.3	if (n > 0) { /* process pending buffer */
249			rt_compute(rt_buf, n);
250			while (n-- > 0)
251			vb[buf_vh[n]+hsize] = luminance(rt_buf+3*n);
252			}
253	greg	1.1	}
254
255
256			rt_compute(pb, np) /* process buffer through rtrace */
257			float *pb;
258			int np;
259			{
260	greg	1.4	#ifdef DEBUG
261	greg	1.1	if (verbose && np > 1)
262			fprintf(stderr, "%s: sending %d samples to rtrace...\n",
263			progname, np);
264	greg	1.4	#endif
265	greg	1.20	bzero(pb+6np, 6sizeof(float));
266	greg	1.19	if (process(rt_pd, pb, pb, 3sizeof(float)np,
267			6sizeof(float)(np+1)) < 3sizeof(float)np) {
268			fprintf(stderr, "%s: rtrace communication error\n",
269	greg	1.1	progname);
270			exit(1);
271			}
272			}
273
274
275			getexpos(s) /* get exposure from header line */
276			char *s;
277			{
278	greg	1.13	char fmt[32];
279
280	greg	1.1	if (isexpos(s))
281			exposure *= exposval(s);
282	greg	1.13	else if (isformat(s)) {
283			formatval(fmt, s);
284			wrongformat = strcmp(fmt, COLRFMT);
285			}
286	greg	1.1	}
287
288
289			open_pict(fn) /* open picture file */
290			char *fn;
291			{
292			if ((pictfp = fopen(fn, "r")) == NULL) {
293			fprintf("%s: cannot open\n", fn);
294			exit(1);
295			}
296			exposure = 1.0;
297	greg	1.13	getheader(pictfp, getexpos, NULL);
298	greg	1.21	if (wrongformat \|\| !fscnresolu(&pxsiz, &pysiz, pictfp)) {
299			fprintf(stderr, "%s: incompatible picture format\n", fn);
300	greg	1.1	exit(1);
301			}
302	greg	1.8	initscans();
303	greg	1.1	}
304
305
306			close_pict() /* done with picture */
307			{
308			if (pictfp == NULL)
309			return;
310			fclose(pictfp);
311	greg	1.8	donescans();
312	greg	1.1	pictfp = NULL;
313			}
314
315
316			fork_rtrace(av) /* open pipe and start rtrace */
317			char *av[];
318			{
319	greg	1.19	int rval;
320	greg	1.1
321	greg	1.19	rval = open_process(rt_pd, av);
322			if (rval < 0) {
323	greg	1.1	perror(progname);
324			exit(1);
325			}
326	greg	1.19	if (rval == 0) {
327			fprintf(stderr, "%s: command not found\n", av[0]);
328	greg	1.1	exit(1);
329			}
330	greg	1.19	maxpix = rval/(6*sizeof(float));
331			if (maxpix > MAXPIX)
332			maxpix = MAXPIX;
333			maxpix--;
334	greg	1.1	}
335
336
337			done_rtrace() /* wait for rtrace to finish */
338			{
339	greg	1.19	int status;
340	greg	1.1
341	greg	1.19	status = close_process(rt_pd);
342			if (status > 0) {
343	greg	1.1	fprintf(stderr, "%s: bad status (%d) from rtrace\n",
344			progname, status);
345			exit(1);
346			}
347	greg	1.19	rt_pd[0] = -1;
348	greg	1.8	}
349
350
351			SCAN *
352			scanretire() /* retire old scanlines to free list */
353			{
354			SCAN *sold[NRETIRE];
355			int n;
356			int h;
357			register SCAN *sl;
358			register int i;
359			/* grab the NRETIRE oldest scanlines */
360			sold[n = 0] = NULL;
361	greg	1.10	for (h = 0; h < HSIZE; h++)
362			for (sl = hashtab[h]; sl != NULL; sl = sl->next) {
363			for (i = n; i && sold[i-1]->lused > sl->lused; i--)
364			if (i < NRETIRE)
365	greg	1.8	sold[i] = sold[i-1];
366			if (i < NRETIRE) {
367	greg	1.10	sold[i] = sl;
368	greg	1.8	if (n < NRETIRE) /* grow list */
369			n++;
370	greg	1.10	}
371			}
372			/* put scanlines into free list */
373			for (i = 0; i < n; i++) {
374			h = shash(sold[i]->y);
375			sl = hashtab[h];
376			if (sl == sold[i])
377			hashtab[h] = sl->next;
378			else {
379			while (sl->next != sold[i]) /* IS in list */
380	greg	1.8	sl = sl->next;
381	greg	1.10	sl->next = sold[i]->next;
382	greg	1.8	}
383	greg	1.10	if (i > 0) { /* save oldest as return value */
384			sold[i]->next = freelist;
385			freelist = sold[i];
386			}
387	greg	1.8	}
388			return(sold[0]);
389			}
390
391
392			static char *scan_buf;
393
394
395			initscans() /* initialize scanline buffers */
396			{
397			int scansize;
398			register SCAN *ptr;
399			register int i;
400			/* initialize positions */
401			scanpos = (long )malloc(pysizsizeof(long));
402			if (scanpos == NULL)
403			memerr("scanline positions");
404			for (i = pysiz-1; i >= 0; i--)
405			scanpos[i] = -1L;
406			curpos = pysiz-1;
407			/* clear hash table */
408			for (i = 0; i < HSIZE; i++)
409			hashtab[i] = NULL;
410			/* allocate scanline buffers */
411			scansize = sizeof(SCAN) + pxsiz*sizeof(COLR);
412			#ifdef ALIGN
413	greg	1.17	scansize = scansize+(sizeof(ALIGN)-1) & ~(sizeof(ALIGN)-1);
414	greg	1.8	#endif
415			i = MAXSBUF / scansize; /* compute number to allocate */
416			if (i > HSIZE)
417			i = HSIZE;
418			scan_buf = malloc(iscansize); / get in one big chunk */
419			if (scan_buf == NULL)
420			memerr("scanline buffers");
421			ptr = (SCAN *)scan_buf;
422			freelist = NULL; /* build our free list */
423			while (i-- > 0) {
424			ptr->y = -1;
425			ptr->lused = -1;
426			ptr->next = freelist;
427			freelist = ptr;
428			ptr = (SCAN )((char )ptr + scansize); /* beware of C bugs */
429			}
430			}
431
432
433			donescans() /* free up scanlines */
434			{
435			free(scan_buf);
436			free((char *)scanpos);
437	greg	1.1	}