src/rt/srcdraw.c

#ifndef lint
static const char       RCSid[] = "$Id: srcdraw.c,v 2.15 2004/10/26 19:04:32 greg Exp $";
#endif
/*
 * Draw small sources into image in case we missed them.
 *
 *  External symbols declared in ray.h
 */

#include "copyright.h"

#include  "ray.h"
#include  "view.h"
#include  "otypes.h"
#include  "source.h"


#define CLIP_ABOVE      1
#define CLIP_BELOW      2
#define CLIP_RIGHT      3
#define CLIP_LEFT       4

#define MAXVERT         10

typedef struct splist {
        struct splist   *next;                  /* next source in list */
        int     sn;                             /* source number */
        short   nv;                             /* number of vertices */
        RREAL   vl[3][2];                       /* vertex array (last) */
} SPLIST;                               /* source polygon list */

extern VIEW     ourview;                /* our view parameters */
extern int      hres, vres;             /* our image resolution */
static SPLIST   *sphead = NULL;         /* our list of source polys */

static int inregion(RREAL p[2], double cv, int crit);
static void clipregion(RREAL a[2], RREAL b[2], double cv, int crit, RREAL r[2]);
static int hp_clip_poly(RREAL vl[][2], int nv, double cv, int crit,
                RREAL vlo[][2]);
static int box_clip_poly(RREAL vl[MAXVERT][2], int nv,
                double xl, double xr, double yb, double ya, RREAL vlo[MAXVERT][2]);
static double minw2(RREAL vl[][2], int nv, double ar2);
static void convex_center(RREAL vl[][2], int nv, RREAL cv[2]);
static double poly_area(RREAL vl[][2], int nv);
static int convex_hull(RREAL vl[][2], int nv, RREAL vlo[][2]);
static void spinsert(int sn, RREAL vl[][2], int nv);
static int sourcepoly(int sn, RREAL sp[MAXVERT][2]);


static int
inregion(                       /* check if vertex is in region */
        RREAL   p[2],
        double  cv,
        int     crit
)
{
        switch (crit) {
        case CLIP_ABOVE:
                return(p[1] < cv);
        case CLIP_BELOW:
                return(p[1] >= cv);
        case CLIP_RIGHT:
                return(p[0] < cv);
        case CLIP_LEFT:
                return(p[0] >= cv);
        }
        return(-1);
}


static void
clipregion(             /* find intersection with boundary */
        register RREAL  a[2],
        register RREAL  b[2],
        double  cv,
        int     crit,
        RREAL   r[2]    /* return value */
)
{
        switch (crit) {
        case CLIP_ABOVE:
        case CLIP_BELOW:
                r[1] = cv;
                r[0] = a[0] + (cv-a[1])/(b[1]-a[1])*(b[0]-a[0]);
                return;
        case CLIP_RIGHT:
        case CLIP_LEFT:
                r[0] = cv;
                r[1] = a[1] + (cv-a[0])/(b[0]-a[0])*(b[1]-a[1]);
                return;
        }
}


static int
hp_clip_poly(   /* clip polygon to half-plane */
        RREAL   vl[][2],
        int     nv,
        double  cv,
        int     crit,
        RREAL   vlo[][2]        /* return value */
)
{
        RREAL   *s, *p;
        register int    j, nvo;

        s = vl[nv-1];
        nvo = 0;
        for (j = 0; j < nv; j++) {
                p = vl[j];
                if (inregion(p, cv, crit)) {
                        if (!inregion(s, cv, crit))
                                clipregion(s, p, cv, crit, vlo[nvo++]);
                        vlo[nvo][0] = p[0]; vlo[nvo++][1] = p[1];
                } else if (inregion(s, cv, crit))
                        clipregion(s, p, cv, crit, vlo[nvo++]);
                s = p;
        }
        return(nvo);
}


static int
box_clip_poly(  /* clip polygon to box */
        RREAL   vl[MAXVERT][2],
        int     nv,
        double  xl,
        double  xr,
        double  yb,
        double  ya,
        RREAL   vlo[MAXVERT][2] /* return value */
)
{
        RREAL   vlt[MAXVERT][2];
        int     nvt, nvo;

        nvt = hp_clip_poly(vl, nv, yb, CLIP_BELOW, vlt);
        nvo = hp_clip_poly(vlt, nvt, ya, CLIP_ABOVE, vlo);
        nvt = hp_clip_poly(vlo, nvo, xl, CLIP_LEFT, vlt);
        nvo = hp_clip_poly(vlt, nvt, xr, CLIP_RIGHT, vlo);

        return(nvo);
}


static double
minw2(                  /* compute square of minimum width */
        RREAL   vl[][2],
        int     nv,
        double  ar2
)
{
        double  d2, w2, w2min, w2max;
        register RREAL  *p0, *p1, *p2;
        int     i, j;
                                /* find minimum for all widths */
        w2min = FHUGE;
        p0 = vl[nv-1];
        for (i = 0; i < nv; i++) {      /* for each edge */
                p1 = vl[i];
                d2 = (p1[0]-p0[0])*(p1[0]-p0[0]) +
                                (p1[1]-p0[1])*(p1[1]-p0[1])*ar2;
                w2max = 0.;             /* find maximum for this side */
                for (j = 1; j < nv-1; j++) {
                        p2 = vl[(i+j)%nv];
                        w2 = (p1[0]-p0[0])*(p2[1]-p0[1]) -
                                        (p1[1]-p0[1])*(p2[0]-p0[0]);
                        w2 = w2*w2*ar2/d2;      /* triangle height squared */
                        if (w2 > w2max)
                                w2max = w2;
                }
                if (w2max < w2min)      /* global min. based on local max.'s */
                        w2min = w2max;
                p0 = p1;
        }
        return(w2min);
}


static void
convex_center(          /* compute center of convex polygon */
        register RREAL  vl[][2],
        int     nv,
        RREAL   cv[2]           /* return value */
)
{
        register int    i;
                                        /* simple average (suboptimal) */
        cv[0] = cv[1] = 0.;
        for (i = 0; i < nv; i++) {
                cv[0] += vl[i][0];
                cv[1] += vl[i][1];
        }
        cv[0] /= (double)nv;
        cv[1] /= (double)nv;
}


static double
poly_area(                      /* compute area of polygon */
        register RREAL  vl[][2],
        int     nv
)
{
        double  a;
        RREAL   v0[2], v1[2];
        register int    i;

        a = 0.;
        v0[0] = vl[1][0] - vl[0][0];
        v0[1] = vl[1][1] - vl[0][1];
        for (i = 2; i < nv; i++) {
                v1[0] = vl[i][0] - vl[0][0];
                v1[1] = vl[i][1] - vl[0][1];
                a += v0[0]*v1[1] - v0[1]*v1[0];
                v0[0] = v1[0]; v0[1] = v1[1];
        }
        return(a * (a >= 0. ? .5 : -.5));
}


static int
convex_hull(            /* compute polygon's convex hull */
        RREAL   vl[][2],
        int     nv,
        RREAL   vlo[][2]        /* return value */
)
{
        int     nvo, nvt;
        RREAL   vlt[MAXVERT][2];
        double  voa, vta;
        register int    i, j;
                                        /* start with original polygon */
        for (i = nvo = nv; i--; ) {
                vlo[i][0] = vl[i][0]; vlo[i][1] = vl[i][1];
        }
        voa = poly_area(vlo, nvo);      /* compute its area */
        for (i = 0; i < nvo; i++) {             /* for each output vertex */
                for (j = 0; j < i; j++) {
                        vlt[j][0] = vlo[j][0]; vlt[j][1] = vlo[j][1];
                }
                nvt = nvo - 1;                  /* make poly w/o vertex */
                for (j = i; j < nvt; j++) {
                        vlt[j][0] = vlo[j+1][0]; vlt[j][1] = vlo[j+1][1];
                }
                vta = poly_area(vlt, nvt);
                if (vta >= voa) {               /* is simpler poly bigger? */
                        voa = vta;                      /* then use it */
                        for (j = nvo = nvt; j--; ) {
                                vlo[j][0] = vlt[j][0]; vlo[j][1] = vlt[j][1];
                        }
                        i--;                            /* next adjust */
                }
        }
        return(nvo);
}


static void
spinsert(                       /* insert new source polygon */
        int     sn,
        RREAL   vl[][2],
        int     nv
)
{
        register SPLIST *spn;
        register int    i;

        if (nv < 3)
                return;
        if (nv > 3)
                spn = (SPLIST *)malloc(sizeof(SPLIST)+sizeof(RREAL)*2*(nv-3));
        else
                spn = (SPLIST *)malloc(sizeof(SPLIST));
        if (spn == NULL)
                error(SYSTEM, "out of memory in spinsert");
        spn->sn = sn;
        for (i = spn->nv = nv; i--; ) {
                spn->vl[i][0] = vl[i][0]; spn->vl[i][1] = vl[i][1];
        }
        spn->next = sphead;             /* push onto global list */
        sphead = spn;
}


static int
sourcepoly(                     /* compute image polygon for source */
        int     sn,
        RREAL   sp[MAXVERT][2]
)
{
        static short    cubeord[8][6] = {{1,3,2,6,4,5},{0,4,5,7,3,2},
                                         {0,1,3,7,6,4},{0,1,5,7,6,2},
                                         {0,2,6,7,5,1},{0,4,6,7,3,1},
                                         {0,2,3,7,5,4},{1,5,4,6,2,3}};
        register SRCREC *s = source + sn;
        FVECT   ap, ip;
        RREAL   pt[6][2];
        int     dir;
        register int    i, j;

        if (s->sflags & (SDISTANT|SFLAT)) {
                if (s->sflags & SDISTANT) {
                        if (ourview.type == VT_PAR)
                                return(0);      /* all or nothing case */
                        if (s->srad >= 0.05)
                                return(0);      /* should never be a problem */
                }
                if (s->sflags & SFLAT) {
                        for (i = 0; i < 3; i++)
                                ap[i] = s->sloc[i] - ourview.vp[i];
                        if (DOT(ap, s->snorm) >= 0.)
                                return(0);      /* source faces away */
                }
                for (j = 0; j < 4; j++) {       /* four corners */
                        for (i = 0; i < 3; i++) {
                                ap[i] = s->sloc[i];
                                if ((j==1)|(j==2)) ap[i] += s->ss[SU][i];
                                else ap[i] -= s->ss[SU][i];
                                if ((j==2)|(j==3)) ap[i] += s->ss[SV][i];
                                else ap[i] -= s->ss[SV][i];
                                if (s->sflags & SDISTANT) {
                                        ap[i] *= 1. + ourview.vfore;
                                        ap[i] += ourview.vp[i];
                                }
                        }
                        viewloc(ip, &ourview, ap);      /* find image point */
                        if (ip[2] <= 0.)
                                return(0);              /* in front of view */
                        sp[j][0] = ip[0]; sp[j][1] = ip[1];
                }
                return(4);
        }
                                        /* identify furthest corner */
        for (i = 0; i < 3; i++)
                ap[i] = s->sloc[i] - ourview.vp[i];
        dir =   (DOT(ap,s->ss[SU])>0.) |
                (DOT(ap,s->ss[SV])>0.)<<1 |
                (DOT(ap,s->ss[SW])>0.)<<2 ;
                                        /* order vertices based on this */
        for (j = 0; j < 6; j++) {
                for (i = 0; i < 3; i++) {
                        ap[i] = s->sloc[i];
                        if (cubeord[dir][j] & 1) ap[i] += s->ss[SU][i];
                        else ap[i] -= s->ss[SU][i];
                        if (cubeord[dir][j] & 2) ap[i] += s->ss[SV][i];
                        else ap[i] -= s->ss[SV][i];
                        if (cubeord[dir][j] & 4) ap[i] += s->ss[SW][i];
                        else ap[i] -= s->ss[SW][i];
                }
                viewloc(ip, &ourview, ap);      /* find image point */
                if (ip[2] <= 0.)
                        return(0);              /* in front of view */
                pt[j][0] = ip[0]; pt[j][1] = ip[1];
        }
        return(convex_hull(pt, 6, sp));         /* make sure it's convex */
}


                        /* initialize by finding sources smaller than rad */
extern void
init_drawsources(
        int     rad                             /* source sample size */
)
{
        RREAL   spoly[MAXVERT][2];
        int     nsv;
        register SPLIST *sp;
        register int    i;
                                        /* free old source list if one */
        for (sp = sphead; sp != NULL; sp = sphead) {
                sphead = sp->next;
                free((void *)sp);
        }
                                        /* loop through all sources */
        for (i = nsources; i--; ) {
                                        /* skip illum's */
                if (findmaterial(source[i].so)->otype == MAT_ILLUM)
                        continue;
                                        /* compute image polygon for source */
                if (!(nsv = sourcepoly(i, spoly)))
                        continue;
                                        /* clip to image boundaries */
                if (!(nsv = box_clip_poly(spoly, nsv, 0., 1., 0., 1., spoly)))
                        continue;
                                        /* big enough for standard sampling? */
                if (minw2(spoly, nsv, ourview.vn2/ourview.hn2) >
                                (double)rad*rad/hres/hres)
                        continue;
                                        /* OK, add to our list */
                spinsert(i, spoly, nsv);
        }
}

extern void                     /* add sources smaller than rad to computed subimage */
drawsources(
        COLOR   *pic[],                         /* subimage pixel value array */
        float   *zbf[],                         /* subimage distance array (opt.) */
        int     x0,                             /* origin and size of subimage */
        int     xsiz,
        int     y0,
        int     ysiz
)
{
        RREAL   spoly[MAXVERT][2], ppoly[MAXVERT][2];
        int     nsv, npv;
        int     xmin, xmax, ymin, ymax, x, y;
        RREAL   cxy[2];
        double  w;
        RAY     sr;
        register SPLIST *sp;
        register int    i;
                                        /* check each source in our list */
        for (sp = sphead; sp != NULL; sp = sp->next) {
                                        /* clip source poly to subimage */
                nsv = box_clip_poly(sp->vl, sp->nv,
                                (double)x0/hres, (double)(x0+xsiz)/hres,
                                (double)y0/vres, (double)(y0+ysiz)/vres, spoly);
                if (!nsv)
                        continue;
                                        /* find common subimage (BBox) */
                xmin = x0 + xsiz; xmax = x0;
                ymin = y0 + ysiz; ymax = y0;
                for (i = 0; i < nsv; i++) {
                        if ((double)xmin/hres > spoly[i][0])
                                xmin = spoly[i][0]*hres + FTINY;
                        if ((double)xmax/hres < spoly[i][0])
                                xmax = spoly[i][0]*hres - FTINY;
                        if ((double)ymin/vres > spoly[i][1])
                                ymin = spoly[i][1]*vres + FTINY;
                        if ((double)ymax/vres < spoly[i][1])
                                ymax = spoly[i][1]*vres - FTINY;
                }
                                        /* evaluate each pixel in BBox */
                for (y = ymin; y <= ymax; y++)
                        for (x = xmin; x <= xmax; x++) {
                                                        /* subarea for pixel */
                                npv = box_clip_poly(spoly, nsv,
                                                (double)x/hres, (x+1.)/hres,
                                                (double)y/vres, (y+1.)/vres,
                                                ppoly);
                                if (!npv)
                                        continue;       /* no overlap */
                                convex_center(ppoly, npv, cxy);
                                if ((sr.rmax = viewray(sr.rorg,sr.rdir,&ourview,
                                                cxy[0],cxy[1])) < -FTINY)
                                        continue;       /* not in view */
                                if (source[sp->sn].sflags & SSPOT &&
                                                spotout(&sr, source[sp->sn].sl.s))
                                        continue;       /* outside spot */
                                rayorigin(&sr, SHADOW, NULL, NULL);
                                sr.rsrc = sp->sn;
                                rayvalue(&sr);          /* compute value */
                                if (bright(sr.rcol) <= FTINY)
                                        continue;       /* missed/blocked */
                                                        /* modify pixel */
                                w = poly_area(ppoly, npv) * hres * vres;
                                if (zbf[y-y0] != NULL &&
                                                sr.rt < 0.99*zbf[y-y0][x-x0]) {
                                        zbf[y-y0][x-x0] = sr.rt;
                                } else if (!bigdiff(sr.rcol, pic[y-y0][x-x0],
                                                0.01)) { /* source sample */
                                        scalecolor(pic[y-y0][x-x0], w);
                                        continue;
                                }
                                scalecolor(sr.rcol, w);
                                scalecolor(pic[y-y0][x-x0], 1.-w);
                                addcolor(pic[y-y0][x-x0], sr.rcol);
                        }
        }
}
Revision:	2.16
Committed:	Tue Apr 19 01:15:07 2005 UTC (19 years ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R7P2, rad3R7P1, rad4R1, rad4R0, rad3R8, rad3R9
Changes since 2.15:	+2 -2 lines
Log Message:	Extensive changes to enable rtrace -oTW option for tracking ray contributions
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.16	static const char RCSid[] = "$Id: srcdraw.c,v 2.15 2004/10/26 19:04:32 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* Draw small sources into image in case we missed them.
6	greg	2.5	*
7			* External symbols declared in ray.h
8			*/
9
10	greg	2.6	#include "copyright.h"
11	greg	2.1
12			#include "ray.h"
13			#include "view.h"
14	greg	2.15	#include "otypes.h"
15	greg	2.1	#include "source.h"
16
17
18			#define CLIP_ABOVE 1
19			#define CLIP_BELOW 2
20			#define CLIP_RIGHT 3
21			#define CLIP_LEFT 4
22
23			#define MAXVERT 10
24
25	greg	2.3	typedef struct splist {
26			struct splist next; / next source in list */
27			int sn; /* source number */
28			short nv; /* number of vertices */
29	schorsch	2.7	RREAL vl[3][2]; /* vertex array (last) */
30	greg	2.3	} SPLIST; /* source polygon list */
31	greg	2.1
32	greg	2.3	extern VIEW ourview; /* our view parameters */
33			extern int hres, vres; /* our image resolution */
34			static SPLIST sphead = NULL; / our list of source polys */
35
36	schorsch	2.11	static int inregion(RREAL p[2], double cv, int crit);
37			static void clipregion(RREAL a[2], RREAL b[2], double cv, int crit, RREAL r[2]);
38			static int hp_clip_poly(RREAL vl[][2], int nv, double cv, int crit,
39			RREAL vlo[][2]);
40			static int box_clip_poly(RREAL vl[MAXVERT][2], int nv,
41			double xl, double xr, double yb, double ya, RREAL vlo[MAXVERT][2]);
42			static double minw2(RREAL vl[][2], int nv, double ar2);
43			static void convex_center(RREAL vl[][2], int nv, RREAL cv[2]);
44			static double poly_area(RREAL vl[][2], int nv);
45			static int convex_hull(RREAL vl[][2], int nv, RREAL vlo[][2]);
46			static void spinsert(int sn, RREAL vl[][2], int nv);
47			static int sourcepoly(int sn, RREAL sp[MAXVERT][2]);
48
49	greg	2.3
50	greg	2.1	static int
51	schorsch	2.11	inregion( /* check if vertex is in region */
52			RREAL p[2],
53			double cv,
54			int crit
55			)
56	greg	2.1	{
57			switch (crit) {
58			case CLIP_ABOVE:
59			return(p[1] < cv);
60			case CLIP_BELOW:
61			return(p[1] >= cv);
62			case CLIP_RIGHT:
63			return(p[0] < cv);
64			case CLIP_LEFT:
65			return(p[0] >= cv);
66			}
67			return(-1);
68			}
69
70
71	schorsch	2.11	static void
72			clipregion( /* find intersection with boundary */
73			register RREAL a[2],
74			register RREAL b[2],
75			double cv,
76			int crit,
77			RREAL r[2] /* return value */
78			)
79	greg	2.1	{
80			switch (crit) {
81			case CLIP_ABOVE:
82			case CLIP_BELOW:
83			r[1] = cv;
84			r[0] = a[0] + (cv-a[1])/(b[1]-a[1])*(b[0]-a[0]);
85			return;
86			case CLIP_RIGHT:
87			case CLIP_LEFT:
88			r[0] = cv;
89			r[1] = a[1] + (cv-a[0])/(b[0]-a[0])*(b[1]-a[1]);
90			return;
91			}
92			}
93
94
95			static int
96	schorsch	2.11	hp_clip_poly( /* clip polygon to half-plane */
97			RREAL vl[][2],
98			int nv,
99			double cv,
100			int crit,
101			RREAL vlo[][2] /* return value */
102			)
103	greg	2.1	{
104	schorsch	2.7	RREAL s, p;
105	greg	2.1	register int j, nvo;
106
107			s = vl[nv-1];
108			nvo = 0;
109			for (j = 0; j < nv; j++) {
110			p = vl[j];
111			if (inregion(p, cv, crit)) {
112			if (!inregion(s, cv, crit))
113			clipregion(s, p, cv, crit, vlo[nvo++]);
114			vlo[nvo][0] = p[0]; vlo[nvo++][1] = p[1];
115			} else if (inregion(s, cv, crit))
116			clipregion(s, p, cv, crit, vlo[nvo++]);
117			s = p;
118			}
119			return(nvo);
120			}
121
122
123			static int
124	schorsch	2.11	box_clip_poly( /* clip polygon to box */
125			RREAL vl[MAXVERT][2],
126			int nv,
127			double xl,
128			double xr,
129			double yb,
130			double ya,
131			RREAL vlo[MAXVERT][2] /* return value */
132			)
133	greg	2.1	{
134	schorsch	2.7	RREAL vlt[MAXVERT][2];
135	greg	2.1	int nvt, nvo;
136
137			nvt = hp_clip_poly(vl, nv, yb, CLIP_BELOW, vlt);
138			nvo = hp_clip_poly(vlt, nvt, ya, CLIP_ABOVE, vlo);
139			nvt = hp_clip_poly(vlo, nvo, xl, CLIP_LEFT, vlt);
140			nvo = hp_clip_poly(vlt, nvt, xr, CLIP_RIGHT, vlo);
141
142			return(nvo);
143			}
144
145
146			static double
147	schorsch	2.11	minw2( /* compute square of minimum width */
148			RREAL vl[][2],
149			int nv,
150			double ar2
151			)
152	greg	2.1	{
153			double d2, w2, w2min, w2max;
154	schorsch	2.7	register RREAL p0, p1, *p2;
155	greg	2.1	int i, j;
156			/* find minimum for all widths */
157			w2min = FHUGE;
158			p0 = vl[nv-1];
159			for (i = 0; i < nv; i++) { /* for each edge */
160			p1 = vl[i];
161			d2 = (p1[0]-p0[0])*(p1[0]-p0[0]) +
162			(p1[1]-p0[1])(p1[1]-p0[1])ar2;
163			w2max = 0.; /* find maximum for this side */
164			for (j = 1; j < nv-1; j++) {
165			p2 = vl[(i+j)%nv];
166			w2 = (p1[0]-p0[0])*(p2[1]-p0[1]) -
167			(p1[1]-p0[1])*(p2[0]-p0[0]);
168			w2 = w2w2ar2/d2; /* triangle height squared */
169			if (w2 > w2max)
170			w2max = w2;
171			}
172			if (w2max < w2min) /* global min. based on local max.'s */
173			w2min = w2max;
174			p0 = p1;
175			}
176			return(w2min);
177			}
178
179
180	schorsch	2.11	static void
181			convex_center( /* compute center of convex polygon */
182			register RREAL vl[][2],
183			int nv,
184			RREAL cv[2] /* return value */
185			)
186	greg	2.1	{
187			register int i;
188			/* simple average (suboptimal) */
189			cv[0] = cv[1] = 0.;
190			for (i = 0; i < nv; i++) {
191			cv[0] += vl[i][0];
192			cv[1] += vl[i][1];
193			}
194			cv[0] /= (double)nv;
195			cv[1] /= (double)nv;
196			}
197
198
199			static double
200	schorsch	2.11	poly_area( /* compute area of polygon */
201			register RREAL vl[][2],
202			int nv
203			)
204	greg	2.1	{
205			double a;
206	schorsch	2.7	RREAL v0[2], v1[2];
207	greg	2.1	register int i;
208
209			a = 0.;
210			v0[0] = vl[1][0] - vl[0][0];
211			v0[1] = vl[1][1] - vl[0][1];
212			for (i = 2; i < nv; i++) {
213			v1[0] = vl[i][0] - vl[0][0];
214			v1[1] = vl[i][1] - vl[0][1];
215			a += v0[0]v1[1] - v0[1]v1[0];
216			v0[0] = v1[0]; v0[1] = v1[1];
217			}
218			return(a * (a >= 0. ? .5 : -.5));
219			}
220
221
222			static int
223	schorsch	2.11	convex_hull( /* compute polygon's convex hull */
224			RREAL vl[][2],
225			int nv,
226			RREAL vlo[][2] /* return value */
227			)
228	greg	2.1	{
229			int nvo, nvt;
230	schorsch	2.7	RREAL vlt[MAXVERT][2];
231	greg	2.1	double voa, vta;
232			register int i, j;
233			/* start with original polygon */
234			for (i = nvo = nv; i--; ) {
235			vlo[i][0] = vl[i][0]; vlo[i][1] = vl[i][1];
236			}
237			voa = poly_area(vlo, nvo); /* compute its area */
238			for (i = 0; i < nvo; i++) { /* for each output vertex */
239			for (j = 0; j < i; j++) {
240			vlt[j][0] = vlo[j][0]; vlt[j][1] = vlo[j][1];
241			}
242			nvt = nvo - 1; /* make poly w/o vertex */
243			for (j = i; j < nvt; j++) {
244			vlt[j][0] = vlo[j+1][0]; vlt[j][1] = vlo[j+1][1];
245			}
246			vta = poly_area(vlt, nvt);
247			if (vta >= voa) { /* is simpler poly bigger? */
248			voa = vta; /* then use it */
249			for (j = nvo = nvt; j--; ) {
250			vlo[j][0] = vlt[j][0]; vlo[j][1] = vlt[j][1];
251			}
252			i--; /* next adjust */
253			}
254			}
255			return(nvo);
256			}
257
258
259	schorsch	2.11	static void
260			spinsert( /* insert new source polygon */
261			int sn,
262			RREAL vl[][2],
263			int nv
264			)
265	greg	2.3	{
266			register SPLIST *spn;
267			register int i;
268
269			if (nv < 3)
270			return;
271			if (nv > 3)
272	schorsch	2.7	spn = (SPLIST )malloc(sizeof(SPLIST)+sizeof(RREAL)2*(nv-3));
273	greg	2.3	else
274			spn = (SPLIST *)malloc(sizeof(SPLIST));
275			if (spn == NULL)
276			error(SYSTEM, "out of memory in spinsert");
277			spn->sn = sn;
278			for (i = spn->nv = nv; i--; ) {
279			spn->vl[i][0] = vl[i][0]; spn->vl[i][1] = vl[i][1];
280			}
281			spn->next = sphead; /* push onto global list */
282			sphead = spn;
283			}
284
285
286	schorsch	2.11	static int
287			sourcepoly( /* compute image polygon for source */
288			int sn,
289			RREAL sp[MAXVERT][2]
290			)
291	greg	2.1	{
292	greg	2.9	static short cubeord[8][6] = {{1,3,2,6,4,5},{0,4,5,7,3,2},
293	greg	2.1	{0,1,3,7,6,4},{0,1,5,7,6,2},
294			{0,2,6,7,5,1},{0,4,6,7,3,1},
295			{0,2,3,7,5,4},{1,5,4,6,2,3}};
296			register SRCREC *s = source + sn;
297			FVECT ap, ip;
298	schorsch	2.7	RREAL pt[6][2];
299	greg	2.1	int dir;
300			register int i, j;
301
302			if (s->sflags & (SDISTANT\|SFLAT)) {
303	greg	2.12	if (s->sflags & SDISTANT) {
304			if (ourview.type == VT_PAR)
305			return(0); /* all or nothing case */
306			if (s->srad >= 0.05)
307			return(0); /* should never be a problem */
308			}
309	greg	2.1	if (s->sflags & SFLAT) {
310			for (i = 0; i < 3; i++)
311	greg	2.3	ap[i] = s->sloc[i] - ourview.vp[i];
312	greg	2.1	if (DOT(ap, s->snorm) >= 0.)
313			return(0); /* source faces away */
314			}
315			for (j = 0; j < 4; j++) { /* four corners */
316			for (i = 0; i < 3; i++) {
317			ap[i] = s->sloc[i];
318	schorsch	2.8	if ((j==1)\|(j==2)) ap[i] += s->ss[SU][i];
319	greg	2.1	else ap[i] -= s->ss[SU][i];
320	schorsch	2.8	if ((j==2)\|(j==3)) ap[i] += s->ss[SV][i];
321	greg	2.1	else ap[i] -= s->ss[SV][i];
322			if (s->sflags & SDISTANT) {
323	greg	2.3	ap[i] *= 1. + ourview.vfore;
324			ap[i] += ourview.vp[i];
325	greg	2.1	}
326			}
327	greg	2.3	viewloc(ip, &ourview, ap); /* find image point */
328	greg	2.1	if (ip[2] <= 0.)
329			return(0); /* in front of view */
330			sp[j][0] = ip[0]; sp[j][1] = ip[1];
331			}
332			return(4);
333			}
334			/* identify furthest corner */
335			for (i = 0; i < 3; i++)
336	greg	2.3	ap[i] = s->sloc[i] - ourview.vp[i];
337	greg	2.1	dir = (DOT(ap,s->ss[SU])>0.) \|
338			(DOT(ap,s->ss[SV])>0.)<<1 \|
339			(DOT(ap,s->ss[SW])>0.)<<2 ;
340			/* order vertices based on this */
341			for (j = 0; j < 6; j++) {
342			for (i = 0; i < 3; i++) {
343			ap[i] = s->sloc[i];
344			if (cubeord[dir][j] & 1) ap[i] += s->ss[SU][i];
345			else ap[i] -= s->ss[SU][i];
346			if (cubeord[dir][j] & 2) ap[i] += s->ss[SV][i];
347			else ap[i] -= s->ss[SV][i];
348			if (cubeord[dir][j] & 4) ap[i] += s->ss[SW][i];
349			else ap[i] -= s->ss[SW][i];
350			}
351	greg	2.3	viewloc(ip, &ourview, ap); /* find image point */
352	greg	2.1	if (ip[2] <= 0.)
353			return(0); /* in front of view */
354			pt[j][0] = ip[0]; pt[j][1] = ip[1];
355			}
356			return(convex_hull(pt, 6, sp)); /* make sure it's convex */
357			}
358
359
360	greg	2.3	/* initialize by finding sources smaller than rad */
361	schorsch	2.11	extern void
362			init_drawsources(
363			int rad /* source sample size */
364			)
365	greg	2.3	{
366	schorsch	2.7	RREAL spoly[MAXVERT][2];
367	greg	2.3	int nsv;
368			register SPLIST *sp;
369			register int i;
370			/* free old source list if one */
371			for (sp = sphead; sp != NULL; sp = sphead) {
372			sphead = sp->next;
373	greg	2.5	free((void *)sp);
374	greg	2.3	}
375			/* loop through all sources */
376			for (i = nsources; i--; ) {
377	greg	2.15	/* skip illum's */
378			if (findmaterial(source[i].so)->otype == MAT_ILLUM)
379			continue;
380	greg	2.3	/* compute image polygon for source */
381			if (!(nsv = sourcepoly(i, spoly)))
382			continue;
383			/* clip to image boundaries */
384			if (!(nsv = box_clip_poly(spoly, nsv, 0., 1., 0., 1., spoly)))
385			continue;
386			/* big enough for standard sampling? */
387			if (minw2(spoly, nsv, ourview.vn2/ourview.hn2) >
388			(double)rad*rad/hres/hres)
389			continue;
390			/* OK, add to our list */
391			spinsert(i, spoly, nsv);
392			}
393			}
394
395	schorsch	2.11	extern void /* add sources smaller than rad to computed subimage */
396			drawsources(
397			COLOR pic[], / subimage pixel value array */
398			float zbf[], / subimage distance array (opt.) */
399			int x0, /* origin and size of subimage */
400			int xsiz,
401			int y0,
402			int ysiz
403			)
404	greg	2.1	{
405	schorsch	2.7	RREAL spoly[MAXVERT][2], ppoly[MAXVERT][2];
406	greg	2.1	int nsv, npv;
407	greg	2.3	int xmin, xmax, ymin, ymax, x, y;
408	schorsch	2.7	RREAL cxy[2];
409	gregl	2.4	double w;
410	greg	2.1	RAY sr;
411	greg	2.3	register SPLIST *sp;
412			register int i;
413			/* check each source in our list */
414			for (sp = sphead; sp != NULL; sp = sp->next) {
415	greg	2.1	/* clip source poly to subimage */
416	greg	2.3	nsv = box_clip_poly(sp->vl, sp->nv,
417			(double)x0/hres, (double)(x0+xsiz)/hres,
418			(double)y0/vres, (double)(y0+ysiz)/vres, spoly);
419	greg	2.1	if (!nsv)
420			continue;
421			/* find common subimage (BBox) */
422			xmin = x0 + xsiz; xmax = x0;
423			ymin = y0 + ysiz; ymax = y0;
424			for (i = 0; i < nsv; i++) {
425	greg	2.3	if ((double)xmin/hres > spoly[i][0])
426			xmin = spoly[i][0]*hres + FTINY;
427			if ((double)xmax/hres < spoly[i][0])
428			xmax = spoly[i][0]*hres - FTINY;
429			if ((double)ymin/vres > spoly[i][1])
430			ymin = spoly[i][1]*vres + FTINY;
431			if ((double)ymax/vres < spoly[i][1])
432			ymax = spoly[i][1]*vres - FTINY;
433	greg	2.1	}
434			/* evaluate each pixel in BBox */
435			for (y = ymin; y <= ymax; y++)
436			for (x = xmin; x <= xmax; x++) {
437			/* subarea for pixel */
438			npv = box_clip_poly(spoly, nsv,
439	greg	2.3	(double)x/hres, (x+1.)/hres,
440			(double)y/vres, (y+1.)/vres,
441			ppoly);
442	greg	2.1	if (!npv)
443			continue; /* no overlap */
444			convex_center(ppoly, npv, cxy);
445	greg	2.3	if ((sr.rmax = viewray(sr.rorg,sr.rdir,&ourview,
446			cxy[0],cxy[1])) < -FTINY)
447	greg	2.1	continue; /* not in view */
448	greg	2.3	if (source[sp->sn].sflags & SSPOT &&
449			spotout(&sr, source[sp->sn].sl.s))
450	greg	2.1	continue; /* outside spot */
451	greg	2.16	rayorigin(&sr, SHADOW, NULL, NULL);
452	greg	2.15	sr.rsrc = sp->sn;
453	greg	2.1	rayvalue(&sr); /* compute value */
454			if (bright(sr.rcol) <= FTINY)
455			continue; /* missed/blocked */
456			/* modify pixel */
457	greg	2.14	w = poly_area(ppoly, npv) * hres * vres;
458	greg	2.1	if (zbf[y-y0] != NULL &&
459	greg	2.13	sr.rt < 0.99*zbf[y-y0][x-x0]) {
460	greg	2.1	zbf[y-y0][x-x0] = sr.rt;
461	greg	2.13	} else if (!bigdiff(sr.rcol, pic[y-y0][x-x0],
462			0.01)) { /* source sample */
463	greg	2.12	scalecolor(pic[y-y0][x-x0], w);
464	greg	2.13	continue;
465	greg	2.12	}
466	greg	2.13	scalecolor(sr.rcol, w);
467			scalecolor(pic[y-y0][x-x0], 1.-w);
468			addcolor(pic[y-y0][x-x0], sr.rcol);
469	greg	2.1	}
470			}
471			}