src/rt/rview.c

/* Copyright (c) 1987 Regents of the University of California */

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

/*
 *  rview.c - routines and variables for interactive view generation.
 *
 *     3/24/87
 */

#include  "standard.h"

#include  "color.h"

#include  "rpaint.h"

#include  <signal.h>

#include  <ctype.h>

VIEW  ourview = STDVIEW;                /* viewing parameters */
int  hresolu, vresolu;                  /* image resolution */

int  psample = 8;                       /* pixel sample size */
double  maxdiff = .15;                  /* max. sample difference */

double  exposure = 1.0;                 /* exposure for scene */

double  dstrsrc = 0.0;                  /* square source distribution */
double  shadthresh = .1;                /* shadow threshold */
double  shadcert = .25;                 /* shadow certainty */

int  maxdepth = 4;                      /* maximum recursion depth */
double  minweight = 1e-2;               /* minimum ray weight */

COLOR  ambval = BLKCOLOR;               /* ambient value */
double  ambacc = 0.2;                   /* ambient accuracy */
int  ambres = 8;                        /* ambient resolution */
int  ambdiv = 32;                       /* ambient divisions */
int  ambssamp = 0;                      /* ambient super-samples */
int  ambounce = 0;                      /* ambient bounces */
char  *amblist[128];                    /* ambient include/exclude list */
int  ambincl = -1;                      /* include == 1, exclude == 0 */

int  greyscale = 0;                     /* map colors to brightness? */
char  *devname = dev_default;           /* output device name */

struct driver  *dev = NULL;             /* driver functions */

VIEW  oldview;                          /* previous view parameters */

PNODE  ptrunk;                          /* the base of our image */
RECT  pframe;                           /* current frame boundaries */
int  pdepth;                            /* image depth in current frame */

static char  *reserve_mem = NULL;       /* pre-allocated reserve memory */

#define RESERVE_AMT     8192            /* amount of memory to reserve */

#define  CTRL(c)        ('c'-'@')


quit(code)                      /* quit program */
int  code;
{
        devclose();
        exit(code);
}


devopen(dname)                          /* open device driver */
char  *dname;
{
        extern char  *progname, *octname;
        char  *id;
        register int  i;

        id = octname!=NULL ? octname : progname;
                                                /* check device table */
        for (i = 0; devtable[i].name; i++)
                if (!strcmp(dname, devtable[i].name))
                        if ((dev = (*devtable[i].init)(dname, id)) == NULL) {
                                sprintf(errmsg, "cannot initialize %s", dname);
                                error(USER, errmsg);
                        } else
                                return;
                                                /* not there, try exec */
        if ((dev = comm_init(dname, id)) == NULL) {
                sprintf(errmsg, "cannot start device \"%s\"", dname);
                error(USER, errmsg);
        }
}


devclose()                              /* close our device */
{
        if (dev != NULL)
                (*dev->close)();
        dev = NULL;
}


printdevices()                          /* print list of output devices */
{
        register int  i;

        for (i = 0; devtable[i].name; i++)
                printf("%-16s # %s\n", devtable[i].name, devtable[i].descrip);
}


rview()                         /* do a view */
{
        char  buf[32];

        devopen(devname);               /* open device */
        newimage();                     /* set up image */

        for ( ; ; ) {                   /* quit in command() */
                while (hresolu <= 1<<pdepth &&
                                vresolu <= 1<<pdepth)
                        command("done: ");

                if (hresolu <= psample<<pdepth &&
                                vresolu <= psample<<pdepth) {
                        sprintf(buf, "%d sampling...\n", 1<<pdepth);
                        (*dev->comout)(buf);
                        rsample();
                } else {
                        sprintf(buf, "%d refining...\n", 1<<pdepth);
                        (*dev->comout)(buf);
                        refine(&ptrunk, 0, 0, hresolu, vresolu, pdepth+1);
                }
                if (dev->inpready)
                        command(": ");
                else
                        pdepth++;
        }
}


memreserve()                    /* fill memory reserves */
{
        if (reserve_mem != NULL)
                return;                 /* got some already */
        reserve_mem = malloc(RESERVE_AMT);
}


memerror(detail)                /* try and rescue a memory error */
char    *detail;
{
        if (reserve_mem == NULL) {
                sprintf(errmsg, "out of memory %s", detail);
                error(SYSTEM, errmsg);
        }
        free(reserve_mem);
        reserve_mem = NULL;
        for ( ; ; )
                command("out of memory: ");
}


command(prompt)                 /* get/execute command */
char  *prompt;
{
#define  badcom(s)      strncmp(s, inpbuf, args-inpbuf-1)
        double  atof();
        char  inpbuf[256];
        char  *args;
again:
        (*dev->comin)(inpbuf, prompt);          /* get command + arguments */
        for (args = inpbuf; *args && *args != ' '; args++)
                ;
        if (*args) *args++ = '\0';
        else *++args = '\0';
        
        switch (inpbuf[0]) {
        case 'f':                               /* new frame */
                if (badcom("frame"))
                        goto commerr;
                getframe(args);
                break;
        case 'v':                               /* view */
                if (badcom("view"))
                        goto commerr;
                getview(args);
                break;
        case 'l':                               /* last view */
                if (badcom("last"))
                        goto commerr;
                lastview(args);
                break;
        case 'e':                               /* exposure */
                if (badcom("exposure"))
                        goto commerr;
                getexposure(args);
                break;
        case 's':                               /* set a parameter */
                if (badcom("set"))
                        goto commerr;
                setparam(args);
                break;
        case 'n':                               /* new picture */
                if (badcom("new"))
                        goto commerr;
                newimage();
                break;
        case 't':                               /* trace a ray */
                if (badcom("trace"))
                        goto commerr;
                traceray(args);
                break;
        case 'a':                               /* aim camera */
                if (badcom("aim"))
                        goto commerr;
                getaim(args);
                break;
        case 'm':                               /* move camera */
                if (badcom("move"))
                        goto commerr;
                getmove(args);
                break;
        case 'r':                               /* rotate/repaint */
                if (badcom("rotate")) {
                        if (badcom("repaint"))
                                goto commerr;
                        getrepaint(args);
                        break;
                }
                getrotate(args);
                break;
        case 'p':                               /* pivot view */
                if (badcom("pivot"))
                        goto commerr;
                getpivot(args);
                break;
        case CTRL(R):                           /* redraw */
                redraw();
                break;
        case 'w':                               /* write */
                if (badcom("write"))
                        goto commerr;
                writepict(args);
                break;
        case 'q':                               /* quit */
                if (badcom("quit"))
                        goto commerr;
                quit(0);
        case CTRL(C):                           /* interrupt */
                goto again;
#ifdef  SIGTSTP
        case CTRL(Z):                           /* stop */
                devclose();
                kill(0, SIGTSTP);
                /* pc stops here */
                devopen(devname);
                redraw();
                break;
#endif
        case '\0':                              /* continue */
                break;
        default:;
commerr:
                if (iscntrl(inpbuf[0]))
                        sprintf(errmsg, "^%c: unknown control",
                                        inpbuf[0]|0100);
                else
                        sprintf(errmsg, "%s: unknown command", inpbuf);
                error(COMMAND, errmsg);
                break;
        }
#undef  badcom
}


rsample()                       /* sample the image */
{
        int  xsiz, ysiz, y;
        RECT  r;
        PNODE  *p;
        register RECT  *rl;
        register PNODE  **pl;
        register int  x;
        /*
         *     We initialize the bottom row in the image at our current
         * resolution.  During sampling, we check super-pixels to the
         * right and above by calling bigdiff().  If there is a significant
         * difference, we subsample the super-pixels.  The testing process
         * includes initialization of the next row.
         */
        xsiz = (((pframe.r-pframe.l)<<pdepth)+hresolu-1) / hresolu;
        ysiz = (((pframe.u-pframe.d)<<pdepth)+vresolu-1) / vresolu;
        rl = (RECT *)malloc(xsiz*sizeof(RECT));
        if (rl == NULL)
                memerror("in rsample");
        pl = (PNODE **)malloc(xsiz*sizeof(PNODE *));
        if (pl == NULL)
                memerror("in rsample");
        /*
         * Initialize the bottom row.
         */
        rl[0].l = rl[0].d = 0;
        rl[0].r = hresolu; rl[0].u = vresolu;
        pl[0] = findrect(pframe.l, pframe.d, &ptrunk, rl, pdepth);
        for (x = 1; x < xsiz; x++) {
                rl[x].l = rl[x].d = 0;
                rl[x].r = hresolu; rl[x].u = vresolu;
                pl[x] = findrect(pframe.l+((x*hresolu)>>pdepth),
                                pframe.d, &ptrunk, rl+x, pdepth);
        }
                                                /* sample the image */
        for (y = 0; /* y < ysiz */ ; y++) {
                for (x = 0; x < xsiz-1; x++) {
                        if (dev->inpready)
                                goto escape;
                        /*
                         * Test super-pixel to the right.
                         */
                        if (pl[x] != pl[x+1] && bigdiff(pl[x]->v,
                                        pl[x+1]->v, maxdiff)) {
                                refine(pl[x], rl[x].l, rl[x].d,
                                                rl[x].r, rl[x].u, 1);
                                refine(pl[x+1], rl[x+1].l, rl[x+1].d,
                                                rl[x+1].r, rl[x+1].u, 1);
                        }
                }
                if (y >= ysiz-1)
                        break;
                for (x = 0; x < xsiz; x++) {
                        if (dev->inpready)
                                goto escape;
                        /*
                         * Find super-pixel at this position in next row.
                         */
                        r.l = r.d = 0;
                        r.r = hresolu; r.u = vresolu;
                        p = findrect(pframe.l+((x*hresolu)>>pdepth),
                                pframe.d+(((y+1)*vresolu)>>pdepth),
                                        &ptrunk, &r, pdepth);
                        /*
                         * Test super-pixel in next row.
                         */
                        if (pl[x] != p && bigdiff(pl[x]->v, p->v, maxdiff)) {
                                refine(pl[x], rl[x].l, rl[x].d,
                                                rl[x].r, rl[x].u, 1);
                                refine(p, r.l, r.d, r.r, r.u, 1);
                        }
                        /*
                         * Copy into super-pixel array.
                         */
                        rl[x].l = r.l; rl[x].d = r.d;
                        rl[x].r = r.r; rl[x].u = r.u;
                        pl[x] = p;
                }
        }
escape:
        free((char *)rl);
        free((char *)pl);
}


int
refine(p, xmin, ymin, xmax, ymax, pd)           /* refine a node */
register PNODE  *p;
int  xmin, ymin, xmax, ymax;
int  pd;
{
        int  growth;
        int  mx, my;
        int  i;

        if (dev->inpready)                      /* quit for input */
                return(0);

        if (pd <= 0)                            /* depth limit */
                return(0);

        mx = (xmin + xmax) >> 1;
        my = (ymin + ymax) >> 1;
        growth = 0;

        if (p->kid == NULL) {                   /* subdivide */

                if ((p->kid = newptree()) == NULL)
                        memerror("in refine");
                /*
                 *  The following paint order can leave a black pixel
                 *  when redraw() is called in (*dev->paintr)().
                 */
                if (p->x >= mx && p->y >= my)
                        pcopy(p, p->kid+UR);
                else
                        paint(p->kid+UR, mx, my, xmax, ymax);
                if (p->x < mx && p->y >= my)
                        pcopy(p, p->kid+UL);
                else
                        paint(p->kid+UL, xmin, my, mx, ymax);
                if (p->x >= mx && p->y < my)
                        pcopy(p, p->kid+DR);
                else
                        paint(p->kid+DR, mx, ymin, xmax, my);
                if (p->x < mx && p->y < my)
                        pcopy(p, p->kid+DL);
                else
                        paint(p->kid+DL, xmin, ymin, mx, my);

                growth++;
        }
                                                /* do children */
        if (mx > pframe.l) {
                if (my > pframe.d)
                        growth += refine(p->kid+DL, xmin, ymin, mx, my, pd-1);
                if (my < pframe.u)
                        growth += refine(p->kid+UL, xmin, my, mx, ymax, pd-1);
        }
        if (mx < pframe.r) {
                if (my > pframe.d)
                        growth += refine(p->kid+DR, mx, ymin, xmax, my, pd-1);
                if (my < pframe.u)
                        growth += refine(p->kid+UR, mx, my, xmax, ymax, pd-1);
        }
                                                /* recompute sum */
        if (growth) {
                setcolor(p->v, 0.0, 0.0, 0.0);
                for (i = 0; i < 4; i++)
                        addcolor(p->v, p->kid[i].v);
                scalecolor(p->v, 0.25);
        }
        return(growth);
}
Revision:	1.12
Committed:	Fri May 3 15:22:24 1991 UTC (33 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.11:	+31 -3 lines
Log Message:	added minimal memory recovery
#	User	Rev	Content
1	greg	1.1	/* Copyright (c) 1987 Regents of the University of California */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* rview.c - routines and variables for interactive view generation.
9			*
10			* 3/24/87
11			*/
12
13			#include "standard.h"
14
15			#include "color.h"
16
17			#include "rpaint.h"
18
19			#include <signal.h>
20
21			#include <ctype.h>
22
23	greg	1.9	VIEW ourview = STDVIEW; /* viewing parameters */
24			int hresolu, vresolu; /* image resolution */
25	greg	1.1
26			int psample = 8; /* pixel sample size */
27			double maxdiff = .15; /* max. sample difference */
28
29			double exposure = 1.0; /* exposure for scene */
30
31			double dstrsrc = 0.0; /* square source distribution */
32	greg	1.3	double shadthresh = .1; /* shadow threshold */
33	greg	1.4	double shadcert = .25; /* shadow certainty */
34	greg	1.1
35			int maxdepth = 4; /* maximum recursion depth */
36			double minweight = 1e-2; /* minimum ray weight */
37
38			COLOR ambval = BLKCOLOR; /* ambient value */
39			double ambacc = 0.2; /* ambient accuracy */
40	greg	1.5	int ambres = 8; /* ambient resolution */
41	greg	1.1	int ambdiv = 32; /* ambient divisions */
42			int ambssamp = 0; /* ambient super-samples */
43			int ambounce = 0; /* ambient bounces */
44			char amblist[128]; / ambient include/exclude list */
45			int ambincl = -1; /* include == 1, exclude == 0 */
46
47			int greyscale = 0; /* map colors to brightness? */
48	greg	1.11	char devname = dev_default; / output device name */
49	greg	1.1
50			struct driver dev = NULL; / driver functions */
51
52			VIEW oldview; /* previous view parameters */
53
54			PNODE ptrunk; /* the base of our image */
55			RECT pframe; /* current frame boundaries */
56			int pdepth; /* image depth in current frame */
57
58	greg	1.12	static char reserve_mem = NULL; / pre-allocated reserve memory */
59
60			#define RESERVE_AMT 8192 /* amount of memory to reserve */
61
62	greg	1.1	#define CTRL(c) ('c'-'@')
63
64
65			quit(code) /* quit program */
66			int code;
67			{
68			devclose();
69			exit(code);
70			}
71
72
73			devopen(dname) /* open device driver */
74			char *dname;
75			{
76	greg	1.6	extern char progname, octname;
77	greg	1.7	char *id;
78	greg	1.1	register int i;
79	greg	1.6
80	greg	1.7	id = octname!=NULL ? octname : progname;
81	greg	1.1	/* check device table */
82			for (i = 0; devtable[i].name; i++)
83			if (!strcmp(dname, devtable[i].name))
84	greg	1.7	if ((dev = (*devtable[i].init)(dname, id)) == NULL) {
85	greg	1.1	sprintf(errmsg, "cannot initialize %s", dname);
86			error(USER, errmsg);
87			} else
88			return;
89			/* not there, try exec */
90	greg	1.7	if ((dev = comm_init(dname, id)) == NULL) {
91	greg	1.1	sprintf(errmsg, "cannot start device \"%s\"", dname);
92			error(USER, errmsg);
93			}
94			}
95
96
97			devclose() /* close our device */
98			{
99			if (dev != NULL)
100			(*dev->close)();
101			dev = NULL;
102			}
103
104
105			printdevices() /* print list of output devices */
106			{
107			register int i;
108
109			for (i = 0; devtable[i].name; i++)
110			printf("%-16s # %s\n", devtable[i].name, devtable[i].descrip);
111			}
112
113
114			rview() /* do a view */
115			{
116			char buf[32];
117
118			devopen(devname); /* open device */
119			newimage(); /* set up image */
120
121			for ( ; ; ) { /* quit in command() */
122	greg	1.9	while (hresolu <= 1<<pdepth &&
123			vresolu <= 1<<pdepth)
124	greg	1.1	command("done: ");
125
126	greg	1.9	if (hresolu <= psample<<pdepth &&
127			vresolu <= psample<<pdepth) {
128	greg	1.1	sprintf(buf, "%d sampling...\n", 1<<pdepth);
129			(*dev->comout)(buf);
130			rsample();
131			} else {
132			sprintf(buf, "%d refining...\n", 1<<pdepth);
133			(*dev->comout)(buf);
134	greg	1.9	refine(&ptrunk, 0, 0, hresolu, vresolu, pdepth+1);
135	greg	1.1	}
136			if (dev->inpready)
137			command(": ");
138			else
139			pdepth++;
140			}
141			}
142
143
144	greg	1.12	memreserve() /* fill memory reserves */
145			{
146			if (reserve_mem != NULL)
147			return; /* got some already */
148			reserve_mem = malloc(RESERVE_AMT);
149			}
150
151
152			memerror(detail) /* try and rescue a memory error */
153			char *detail;
154			{
155			if (reserve_mem == NULL) {
156			sprintf(errmsg, "out of memory %s", detail);
157			error(SYSTEM, errmsg);
158			}
159			free(reserve_mem);
160			reserve_mem = NULL;
161			for ( ; ; )
162			command("out of memory: ");
163			}
164
165
166	greg	1.1	command(prompt) /* get/execute command */
167			char *prompt;
168			{
169			#define badcom(s) strncmp(s, inpbuf, args-inpbuf-1)
170			double atof();
171			char inpbuf[256];
172			char *args;
173			again:
174	greg	1.10	(dev->comin)(inpbuf, prompt); / get command + arguments */
175	greg	1.1	for (args = inpbuf; args && args != ' '; args++)
176			;
177			if (args) args++ = '\0';
178			else *++args = '\0';
179
180			switch (inpbuf[0]) {
181			case 'f': /* new frame */
182			if (badcom("frame"))
183			goto commerr;
184			getframe(args);
185			break;
186			case 'v': /* view */
187			if (badcom("view"))
188			goto commerr;
189			getview(args);
190			break;
191			case 'l': /* last view */
192			if (badcom("last"))
193			goto commerr;
194			lastview(args);
195			break;
196			case 'e': /* exposure */
197			if (badcom("exposure"))
198			goto commerr;
199			getexposure(args);
200			break;
201			case 's': /* set a parameter */
202			if (badcom("set"))
203			goto commerr;
204			setparam(args);
205			break;
206			case 'n': /* new picture */
207			if (badcom("new"))
208			goto commerr;
209			newimage();
210			break;
211			case 't': /* trace a ray */
212			if (badcom("trace"))
213			goto commerr;
214			traceray(args);
215			break;
216			case 'a': /* aim camera */
217			if (badcom("aim"))
218			goto commerr;
219			getaim(args);
220			break;
221			case 'm': /* move camera */
222			if (badcom("move"))
223			goto commerr;
224			getmove(args);
225			break;
226	greg	1.8	case 'r': /* rotate/repaint */
227			if (badcom("rotate")) {
228			if (badcom("repaint"))
229			goto commerr;
230			getrepaint(args);
231			break;
232			}
233	greg	1.1	getrotate(args);
234			break;
235			case 'p': /* pivot view */
236			if (badcom("pivot"))
237			goto commerr;
238			getpivot(args);
239			break;
240			case CTRL(R): /* redraw */
241			redraw();
242			break;
243			case 'w': /* write */
244			if (badcom("write"))
245			goto commerr;
246			writepict(args);
247			break;
248			case 'q': /* quit */
249			if (badcom("quit"))
250			goto commerr;
251			quit(0);
252			case CTRL(C): /* interrupt */
253			goto again;
254			#ifdef SIGTSTP
255			case CTRL(Z): /* stop */
256			devclose();
257			kill(0, SIGTSTP);
258			/* pc stops here */
259			devopen(devname);
260			redraw();
261			break;
262			#endif
263			case '\0': /* continue */
264			break;
265			default:;
266			commerr:
267			if (iscntrl(inpbuf[0]))
268			sprintf(errmsg, "^%c: unknown control",
269			inpbuf[0]\|0100);
270			else
271			sprintf(errmsg, "%s: unknown command", inpbuf);
272			error(COMMAND, errmsg);
273			break;
274			}
275			#undef badcom
276			}
277
278
279			rsample() /* sample the image */
280			{
281			int xsiz, ysiz, y;
282			RECT r;
283			PNODE *p;
284			register RECT *rl;
285			register PNODE **pl;
286			register int x;
287			/*
288			* We initialize the bottom row in the image at our current
289			* resolution. During sampling, we check super-pixels to the
290			* right and above by calling bigdiff(). If there is a significant
291			* difference, we subsample the super-pixels. The testing process
292			* includes initialization of the next row.
293			*/
294	greg	1.9	xsiz = (((pframe.r-pframe.l)<<pdepth)+hresolu-1) / hresolu;
295			ysiz = (((pframe.u-pframe.d)<<pdepth)+vresolu-1) / vresolu;
296	greg	1.1	rl = (RECT )malloc(xsizsizeof(RECT));
297	greg	1.12	if (rl == NULL)
298			memerror("in rsample");
299	greg	1.1	pl = (PNODE *)malloc(xsizsizeof(PNODE *));
300	greg	1.12	if (pl == NULL)
301			memerror("in rsample");
302	greg	1.1	/*
303			* Initialize the bottom row.
304			*/
305			rl[0].l = rl[0].d = 0;
306	greg	1.9	rl[0].r = hresolu; rl[0].u = vresolu;
307	greg	1.1	pl[0] = findrect(pframe.l, pframe.d, &ptrunk, rl, pdepth);
308			for (x = 1; x < xsiz; x++) {
309			rl[x].l = rl[x].d = 0;
310	greg	1.9	rl[x].r = hresolu; rl[x].u = vresolu;
311			pl[x] = findrect(pframe.l+((x*hresolu)>>pdepth),
312	greg	1.1	pframe.d, &ptrunk, rl+x, pdepth);
313			}
314			/* sample the image */
315			for (y = 0; /* y < ysiz */ ; y++) {
316			for (x = 0; x < xsiz-1; x++) {
317			if (dev->inpready)
318			goto escape;
319			/*
320			* Test super-pixel to the right.
321			*/
322			if (pl[x] != pl[x+1] && bigdiff(pl[x]->v,
323			pl[x+1]->v, maxdiff)) {
324			refine(pl[x], rl[x].l, rl[x].d,
325			rl[x].r, rl[x].u, 1);
326			refine(pl[x+1], rl[x+1].l, rl[x+1].d,
327			rl[x+1].r, rl[x+1].u, 1);
328			}
329			}
330			if (y >= ysiz-1)
331			break;
332			for (x = 0; x < xsiz; x++) {
333			if (dev->inpready)
334			goto escape;
335			/*
336			* Find super-pixel at this position in next row.
337			*/
338			r.l = r.d = 0;
339	greg	1.9	r.r = hresolu; r.u = vresolu;
340			p = findrect(pframe.l+((x*hresolu)>>pdepth),
341			pframe.d+(((y+1)*vresolu)>>pdepth),
342	greg	1.1	&ptrunk, &r, pdepth);
343			/*
344			* Test super-pixel in next row.
345			*/
346			if (pl[x] != p && bigdiff(pl[x]->v, p->v, maxdiff)) {
347			refine(pl[x], rl[x].l, rl[x].d,
348			rl[x].r, rl[x].u, 1);
349			refine(p, r.l, r.d, r.r, r.u, 1);
350			}
351			/*
352			* Copy into super-pixel array.
353			*/
354			rl[x].l = r.l; rl[x].d = r.d;
355			rl[x].r = r.r; rl[x].u = r.u;
356			pl[x] = p;
357			}
358			}
359			escape:
360			free((char *)rl);
361			free((char *)pl);
362			}
363
364
365			int
366			refine(p, xmin, ymin, xmax, ymax, pd) /* refine a node */
367			register PNODE *p;
368			int xmin, ymin, xmax, ymax;
369			int pd;
370			{
371			int growth;
372			int mx, my;
373			int i;
374
375			if (dev->inpready) /* quit for input */
376			return(0);
377
378			if (pd <= 0) /* depth limit */
379			return(0);
380
381			mx = (xmin + xmax) >> 1;
382			my = (ymin + ymax) >> 1;
383			growth = 0;
384
385			if (p->kid == NULL) { /* subdivide */
386
387			if ((p->kid = newptree()) == NULL)
388	greg	1.12	memerror("in refine");
389	greg	1.1	/*
390			* The following paint order can leave a black pixel
391			* when redraw() is called in (*dev->paintr)().
392			*/
393			if (p->x >= mx && p->y >= my)
394			pcopy(p, p->kid+UR);
395			else
396			paint(p->kid+UR, mx, my, xmax, ymax);
397			if (p->x < mx && p->y >= my)
398			pcopy(p, p->kid+UL);
399			else
400			paint(p->kid+UL, xmin, my, mx, ymax);
401			if (p->x >= mx && p->y < my)
402			pcopy(p, p->kid+DR);
403			else
404			paint(p->kid+DR, mx, ymin, xmax, my);
405			if (p->x < mx && p->y < my)
406			pcopy(p, p->kid+DL);
407			else
408			paint(p->kid+DL, xmin, ymin, mx, my);
409
410			growth++;
411			}
412			/* do children */
413			if (mx > pframe.l) {
414			if (my > pframe.d)
415			growth += refine(p->kid+DL, xmin, ymin, mx, my, pd-1);
416			if (my < pframe.u)
417			growth += refine(p->kid+UL, xmin, my, mx, ymax, pd-1);
418			}
419			if (mx < pframe.r) {
420			if (my > pframe.d)
421			growth += refine(p->kid+DR, mx, ymin, xmax, my, pd-1);
422			if (my < pframe.u)
423			growth += refine(p->kid+UR, mx, my, xmax, ymax, pd-1);
424			}
425			/* recompute sum */
426			if (growth) {
427			setcolor(p->v, 0.0, 0.0, 0.0);
428			for (i = 0; i < 4; i++)
429			addcolor(p->v, p->kid[i].v);
430			scalecolor(p->v, 0.25);
431			}
432			return(growth);
433			}