src/rt/srcdraw.c

#ifndef lint
static const char       RCSid[] = "$Id: srcdraw.c,v 2.25 2024/07/03 16:46:43 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  "otspecial.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 */
        RREAL   a[2],
        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;
        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;
        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 */
        RREAL   vl[][2],
        int     nv,
        RREAL   cv[2]           /* return value */
)
{
        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 */
        RREAL   vl[][2],
        int     nv
)
{
        double  a;
        RREAL   v0[2], v1[2];
        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;
        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
)
{
        SPLIST  *spn;
        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}};
        SRCREC  *s = source + sn;
        FVECT   ap, ip;
        RREAL   pt[6][2];
        int     dir;
        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];
                                }
                        }
                                                        /* find image point */
                        if (viewloc(ip, &ourview, ap) != VL_GOOD)
                                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];
                }
                                                /* find image point */
                if (viewloc(ip, &ourview, ap) != VL_GOOD)
                        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 */
void
init_drawsources(
        int     rad                             /* source sample size */
)
{
        RREAL   spoly[MAXVERT][2];
        int     nsv;
        SPLIST  *sp;
        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);
        }
}

void                            /* add sources smaller than rad to computed subimage */
drawsources(
        COLORV  *pic[],                         /* subimage pixel value array */
        int     nc,                             /* number of target components */
        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];
        COLOR   rcol;
        double  w;
        RAY     sr;
        SPLIST  *sp;
        int     i;
                                        /* check #components */
        if ((nc != 3) & (nc != NCSAMP))
                error(INTERNAL, "unsupported #components in drawsources()");
                                        /* 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++) {
                        COLORV  *pp = pic[y-y0] + (xmin-x0)*nc;
                        for (x = xmin; x <= xmax; x++, pp += nc) {
                                                        /* 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 (sintens(sr.rcol) <= FTINY)
                                        continue;       /* missed/blocked */
                                if (nc == 3)
                                        scolor_rgb(rcol, sr.rcol);
                                                        /* modify pixel */
                                w = poly_area(ppoly, npv) * hres * vres;
                                if (zbf[y-y0] != NULL &&
                                                sr.rxt < 0.99*zbf[y-y0][x-x0]) {
                                        zbf[y-y0][x-x0] = sr.rxt;
                                } else if (nc == 3) {
                                        if (!bigdiff(rcol, pp, 0.07)) {
                                                scalecolor(pp, w);
                                                continue;
                                        }
                                } else if (!sbigsdiff(sr.rcol, pp, 0.07)) {
                                        scalescolor(pp, w);
                                        continue;
                                }
                                if (nc == 3) {
                                        scalecolor(rcol, w);
                                        scalecolor(pp, 1.-w);
                                        addcolor(pp, rcol);
                                } else {
                                        scalescolor(sr.rcol, w);
                                        scalescolor(pp, 1.-w);
                                        saddscolor(pp, sr.rcol);
                                }
                        }
                }
        }
}
Revision:	2.26
Committed:	Wed Jul 31 22:21:28 2024 UTC (15 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.25:	+25 -7 lines
Log Message:	fix(rpict): Fixed multi-spectral source drawing bug recently introduced
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.26	static const char RCSid[] = "$Id: srcdraw.c,v 2.25 2024/07/03 16:46:43 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	2.19	#include "otspecial.h"
16	greg	2.1	#include "source.h"
17
18
19			#define CLIP_ABOVE 1
20			#define CLIP_BELOW 2
21			#define CLIP_RIGHT 3
22			#define CLIP_LEFT 4
23
24			#define MAXVERT 10
25
26	greg	2.3	typedef struct splist {
27			struct splist next; / next source in list */
28			int sn; /* source number */
29			short nv; /* number of vertices */
30	schorsch	2.7	RREAL vl[3][2]; /* vertex array (last) */
31	greg	2.3	} SPLIST; /* source polygon list */
32	greg	2.1
33	greg	2.3	extern VIEW ourview; /* our view parameters */
34			extern int hres, vres; /* our image resolution */
35			static SPLIST sphead = NULL; / our list of source polys */
36
37	schorsch	2.11	static int inregion(RREAL p[2], double cv, int crit);
38			static void clipregion(RREAL a[2], RREAL b[2], double cv, int crit, RREAL r[2]);
39			static int hp_clip_poly(RREAL vl[][2], int nv, double cv, int crit,
40			RREAL vlo[][2]);
41			static int box_clip_poly(RREAL vl[MAXVERT][2], int nv,
42			double xl, double xr, double yb, double ya, RREAL vlo[MAXVERT][2]);
43			static double minw2(RREAL vl[][2], int nv, double ar2);
44			static void convex_center(RREAL vl[][2], int nv, RREAL cv[2]);
45			static double poly_area(RREAL vl[][2], int nv);
46			static int convex_hull(RREAL vl[][2], int nv, RREAL vlo[][2]);
47			static void spinsert(int sn, RREAL vl[][2], int nv);
48			static int sourcepoly(int sn, RREAL sp[MAXVERT][2]);
49
50	greg	2.3
51	greg	2.1	static int
52	schorsch	2.11	inregion( /* check if vertex is in region */
53			RREAL p[2],
54			double cv,
55			int crit
56			)
57	greg	2.1	{
58			switch (crit) {
59			case CLIP_ABOVE:
60			return(p[1] < cv);
61			case CLIP_BELOW:
62			return(p[1] >= cv);
63			case CLIP_RIGHT:
64			return(p[0] < cv);
65			case CLIP_LEFT:
66			return(p[0] >= cv);
67			}
68			return(-1);
69			}
70
71
72	schorsch	2.11	static void
73			clipregion( /* find intersection with boundary */
74	greg	2.17	RREAL a[2],
75			RREAL b[2],
76	schorsch	2.11	double cv,
77			int crit,
78			RREAL r[2] /* return value */
79			)
80	greg	2.1	{
81			switch (crit) {
82			case CLIP_ABOVE:
83			case CLIP_BELOW:
84			r[1] = cv;
85			r[0] = a[0] + (cv-a[1])/(b[1]-a[1])*(b[0]-a[0]);
86			return;
87			case CLIP_RIGHT:
88			case CLIP_LEFT:
89			r[0] = cv;
90			r[1] = a[1] + (cv-a[0])/(b[0]-a[0])*(b[1]-a[1]);
91			return;
92			}
93			}
94
95
96			static int
97	schorsch	2.11	hp_clip_poly( /* clip polygon to half-plane */
98			RREAL vl[][2],
99			int nv,
100			double cv,
101			int crit,
102			RREAL vlo[][2] /* return value */
103			)
104	greg	2.1	{
105	schorsch	2.7	RREAL s, p;
106	greg	2.17	int j, nvo;
107	greg	2.1
108			s = vl[nv-1];
109			nvo = 0;
110			for (j = 0; j < nv; j++) {
111			p = vl[j];
112			if (inregion(p, cv, crit)) {
113			if (!inregion(s, cv, crit))
114			clipregion(s, p, cv, crit, vlo[nvo++]);
115			vlo[nvo][0] = p[0]; vlo[nvo++][1] = p[1];
116			} else if (inregion(s, cv, crit))
117			clipregion(s, p, cv, crit, vlo[nvo++]);
118			s = p;
119			}
120			return(nvo);
121			}
122
123
124			static int
125	schorsch	2.11	box_clip_poly( /* clip polygon to box */
126			RREAL vl[MAXVERT][2],
127			int nv,
128			double xl,
129			double xr,
130			double yb,
131			double ya,
132			RREAL vlo[MAXVERT][2] /* return value */
133			)
134	greg	2.1	{
135	schorsch	2.7	RREAL vlt[MAXVERT][2];
136	greg	2.1	int nvt, nvo;
137
138			nvt = hp_clip_poly(vl, nv, yb, CLIP_BELOW, vlt);
139			nvo = hp_clip_poly(vlt, nvt, ya, CLIP_ABOVE, vlo);
140			nvt = hp_clip_poly(vlo, nvo, xl, CLIP_LEFT, vlt);
141			nvo = hp_clip_poly(vlt, nvt, xr, CLIP_RIGHT, vlo);
142
143			return(nvo);
144			}
145
146
147			static double
148	schorsch	2.11	minw2( /* compute square of minimum width */
149			RREAL vl[][2],
150			int nv,
151			double ar2
152			)
153	greg	2.1	{
154			double d2, w2, w2min, w2max;
155	greg	2.17	RREAL p0, p1, *p2;
156	greg	2.1	int i, j;
157			/* find minimum for all widths */
158			w2min = FHUGE;
159			p0 = vl[nv-1];
160			for (i = 0; i < nv; i++) { /* for each edge */
161			p1 = vl[i];
162			d2 = (p1[0]-p0[0])*(p1[0]-p0[0]) +
163			(p1[1]-p0[1])(p1[1]-p0[1])ar2;
164			w2max = 0.; /* find maximum for this side */
165			for (j = 1; j < nv-1; j++) {
166			p2 = vl[(i+j)%nv];
167			w2 = (p1[0]-p0[0])*(p2[1]-p0[1]) -
168			(p1[1]-p0[1])*(p2[0]-p0[0]);
169			w2 = w2w2ar2/d2; /* triangle height squared */
170			if (w2 > w2max)
171			w2max = w2;
172			}
173			if (w2max < w2min) /* global min. based on local max.'s */
174			w2min = w2max;
175			p0 = p1;
176			}
177			return(w2min);
178			}
179
180
181	schorsch	2.11	static void
182			convex_center( /* compute center of convex polygon */
183	greg	2.17	RREAL vl[][2],
184	schorsch	2.11	int nv,
185			RREAL cv[2] /* return value */
186			)
187	greg	2.1	{
188	greg	2.17	int i;
189	greg	2.1	/* simple average (suboptimal) */
190			cv[0] = cv[1] = 0.;
191			for (i = 0; i < nv; i++) {
192			cv[0] += vl[i][0];
193			cv[1] += vl[i][1];
194			}
195			cv[0] /= (double)nv;
196			cv[1] /= (double)nv;
197			}
198
199
200			static double
201	schorsch	2.11	poly_area( /* compute area of polygon */
202	greg	2.17	RREAL vl[][2],
203	schorsch	2.11	int nv
204			)
205	greg	2.1	{
206			double a;
207	schorsch	2.7	RREAL v0[2], v1[2];
208	greg	2.17	int i;
209	greg	2.1
210			a = 0.;
211			v0[0] = vl[1][0] - vl[0][0];
212			v0[1] = vl[1][1] - vl[0][1];
213			for (i = 2; i < nv; i++) {
214			v1[0] = vl[i][0] - vl[0][0];
215			v1[1] = vl[i][1] - vl[0][1];
216			a += v0[0]v1[1] - v0[1]v1[0];
217			v0[0] = v1[0]; v0[1] = v1[1];
218			}
219			return(a * (a >= 0. ? .5 : -.5));
220			}
221
222
223			static int
224	schorsch	2.11	convex_hull( /* compute polygon's convex hull */
225			RREAL vl[][2],
226			int nv,
227			RREAL vlo[][2] /* return value */
228			)
229	greg	2.1	{
230			int nvo, nvt;
231	schorsch	2.7	RREAL vlt[MAXVERT][2];
232	greg	2.1	double voa, vta;
233	greg	2.17	int i, j;
234	greg	2.1	/* start with original polygon */
235			for (i = nvo = nv; i--; ) {
236			vlo[i][0] = vl[i][0]; vlo[i][1] = vl[i][1];
237			}
238			voa = poly_area(vlo, nvo); /* compute its area */
239			for (i = 0; i < nvo; i++) { /* for each output vertex */
240			for (j = 0; j < i; j++) {
241			vlt[j][0] = vlo[j][0]; vlt[j][1] = vlo[j][1];
242			}
243			nvt = nvo - 1; /* make poly w/o vertex */
244			for (j = i; j < nvt; j++) {
245			vlt[j][0] = vlo[j+1][0]; vlt[j][1] = vlo[j+1][1];
246			}
247			vta = poly_area(vlt, nvt);
248			if (vta >= voa) { /* is simpler poly bigger? */
249			voa = vta; /* then use it */
250			for (j = nvo = nvt; j--; ) {
251			vlo[j][0] = vlt[j][0]; vlo[j][1] = vlt[j][1];
252			}
253			i--; /* next adjust */
254			}
255			}
256			return(nvo);
257			}
258
259
260	schorsch	2.11	static void
261			spinsert( /* insert new source polygon */
262			int sn,
263			RREAL vl[][2],
264			int nv
265			)
266	greg	2.3	{
267	greg	2.17	SPLIST *spn;
268			int i;
269	greg	2.3
270			if (nv < 3)
271			return;
272			if (nv > 3)
273	schorsch	2.7	spn = (SPLIST )malloc(sizeof(SPLIST)+sizeof(RREAL)2*(nv-3));
274	greg	2.3	else
275			spn = (SPLIST *)malloc(sizeof(SPLIST));
276			if (spn == NULL)
277			error(SYSTEM, "out of memory in spinsert");
278			spn->sn = sn;
279			for (i = spn->nv = nv; i--; ) {
280			spn->vl[i][0] = vl[i][0]; spn->vl[i][1] = vl[i][1];
281			}
282			spn->next = sphead; /* push onto global list */
283			sphead = spn;
284			}
285
286
287	schorsch	2.11	static int
288			sourcepoly( /* compute image polygon for source */
289			int sn,
290			RREAL sp[MAXVERT][2]
291			)
292	greg	2.1	{
293	greg	2.9	static short cubeord[8][6] = {{1,3,2,6,4,5},{0,4,5,7,3,2},
294	greg	2.1	{0,1,3,7,6,4},{0,1,5,7,6,2},
295			{0,2,6,7,5,1},{0,4,6,7,3,1},
296			{0,2,3,7,5,4},{1,5,4,6,2,3}};
297	greg	2.17	SRCREC *s = source + sn;
298	greg	2.1	FVECT ap, ip;
299	schorsch	2.7	RREAL pt[6][2];
300	greg	2.1	int dir;
301	greg	2.17	int i, j;
302	greg	2.1
303			if (s->sflags & (SDISTANT\|SFLAT)) {
304	greg	2.12	if (s->sflags & SDISTANT) {
305			if (ourview.type == VT_PAR)
306			return(0); /* all or nothing case */
307			if (s->srad >= 0.05)
308			return(0); /* should never be a problem */
309			}
310	greg	2.1	if (s->sflags & SFLAT) {
311			for (i = 0; i < 3; i++)
312	greg	2.3	ap[i] = s->sloc[i] - ourview.vp[i];
313	greg	2.1	if (DOT(ap, s->snorm) >= 0.)
314			return(0); /* source faces away */
315			}
316			for (j = 0; j < 4; j++) { /* four corners */
317			for (i = 0; i < 3; i++) {
318			ap[i] = s->sloc[i];
319	schorsch	2.8	if ((j==1)\|(j==2)) ap[i] += s->ss[SU][i];
320	greg	2.1	else ap[i] -= s->ss[SU][i];
321	schorsch	2.8	if ((j==2)\|(j==3)) ap[i] += s->ss[SV][i];
322	greg	2.1	else ap[i] -= s->ss[SV][i];
323			if (s->sflags & SDISTANT) {
324	greg	2.3	ap[i] *= 1. + ourview.vfore;
325			ap[i] += ourview.vp[i];
326	greg	2.1	}
327			}
328	greg	2.18	/* find image point */
329	greg	2.21	if (viewloc(ip, &ourview, ap) != VL_GOOD)
330	greg	2.1	return(0); /* in front of view */
331			sp[j][0] = ip[0]; sp[j][1] = ip[1];
332			}
333			return(4);
334			}
335			/* identify furthest corner */
336			for (i = 0; i < 3; i++)
337	greg	2.3	ap[i] = s->sloc[i] - ourview.vp[i];
338	greg	2.1	dir = (DOT(ap,s->ss[SU])>0.) \|
339			(DOT(ap,s->ss[SV])>0.)<<1 \|
340			(DOT(ap,s->ss[SW])>0.)<<2 ;
341			/* order vertices based on this */
342			for (j = 0; j < 6; j++) {
343			for (i = 0; i < 3; i++) {
344			ap[i] = s->sloc[i];
345			if (cubeord[dir][j] & 1) ap[i] += s->ss[SU][i];
346			else ap[i] -= s->ss[SU][i];
347			if (cubeord[dir][j] & 2) ap[i] += s->ss[SV][i];
348			else ap[i] -= s->ss[SV][i];
349			if (cubeord[dir][j] & 4) ap[i] += s->ss[SW][i];
350			else ap[i] -= s->ss[SW][i];
351			}
352	greg	2.18	/* find image point */
353	greg	2.21	if (viewloc(ip, &ourview, ap) != VL_GOOD)
354	greg	2.1	return(0); /* in front of view */
355			pt[j][0] = ip[0]; pt[j][1] = ip[1];
356			}
357			return(convex_hull(pt, 6, sp)); /* make sure it's convex */
358			}
359
360
361	greg	2.3	/* initialize by finding sources smaller than rad */
362	greg	2.17	void
363	schorsch	2.11	init_drawsources(
364			int rad /* source sample size */
365			)
366	greg	2.3	{
367	schorsch	2.7	RREAL spoly[MAXVERT][2];
368	greg	2.3	int nsv;
369	greg	2.17	SPLIST *sp;
370			int i;
371	greg	2.3	/* free old source list if one */
372			for (sp = sphead; sp != NULL; sp = sphead) {
373			sphead = sp->next;
374	greg	2.5	free((void *)sp);
375	greg	2.3	}
376			/* loop through all sources */
377			for (i = nsources; i--; ) {
378	greg	2.15	/* skip illum's */
379			if (findmaterial(source[i].so)->otype == MAT_ILLUM)
380			continue;
381	greg	2.3	/* compute image polygon for source */
382			if (!(nsv = sourcepoly(i, spoly)))
383			continue;
384			/* clip to image boundaries */
385			if (!(nsv = box_clip_poly(spoly, nsv, 0., 1., 0., 1., spoly)))
386			continue;
387			/* big enough for standard sampling? */
388			if (minw2(spoly, nsv, ourview.vn2/ourview.hn2) >
389			(double)rad*rad/hres/hres)
390			continue;
391			/* OK, add to our list */
392			spinsert(i, spoly, nsv);
393			}
394			}
395
396	greg	2.17	void /* add sources smaller than rad to computed subimage */
397	schorsch	2.11	drawsources(
398	greg	2.23	COLORV pic[], / subimage pixel value array */
399	greg	2.26	int nc, /* number of target components */
400	schorsch	2.11	float zbf[], / subimage distance array (opt.) */
401			int x0, /* origin and size of subimage */
402			int xsiz,
403			int y0,
404			int ysiz
405			)
406	greg	2.1	{
407	schorsch	2.7	RREAL spoly[MAXVERT][2], ppoly[MAXVERT][2];
408	greg	2.1	int nsv, npv;
409	greg	2.3	int xmin, xmax, ymin, ymax, x, y;
410	schorsch	2.7	RREAL cxy[2];
411	greg	2.26	COLOR rcol;
412	gregl	2.4	double w;
413	greg	2.1	RAY sr;
414	greg	2.17	SPLIST *sp;
415			int i;
416	greg	2.26	/* check #components */
417			if ((nc != 3) & (nc != NCSAMP))
418			error(INTERNAL, "unsupported #components in drawsources()");
419	greg	2.3	/* check each source in our list */
420			for (sp = sphead; sp != NULL; sp = sp->next) {
421	greg	2.1	/* clip source poly to subimage */
422	greg	2.3	nsv = box_clip_poly(sp->vl, sp->nv,
423			(double)x0/hres, (double)(x0+xsiz)/hres,
424			(double)y0/vres, (double)(y0+ysiz)/vres, spoly);
425	greg	2.1	if (!nsv)
426			continue;
427			/* find common subimage (BBox) */
428			xmin = x0 + xsiz; xmax = x0;
429			ymin = y0 + ysiz; ymax = y0;
430			for (i = 0; i < nsv; i++) {
431	greg	2.3	if ((double)xmin/hres > spoly[i][0])
432			xmin = spoly[i][0]*hres + FTINY;
433			if ((double)xmax/hres < spoly[i][0])
434			xmax = spoly[i][0]*hres - FTINY;
435			if ((double)ymin/vres > spoly[i][1])
436			ymin = spoly[i][1]*vres + FTINY;
437			if ((double)ymax/vres < spoly[i][1])
438			ymax = spoly[i][1]*vres - FTINY;
439	greg	2.1	}
440			/* evaluate each pixel in BBox */
441	greg	2.23	for (y = ymin; y <= ymax; y++) {
442	greg	2.26	COLORV pp = pic[y-y0] + (xmin-x0)nc;
443			for (x = xmin; x <= xmax; x++, pp += nc) {
444	greg	2.1	/* subarea for pixel */
445			npv = box_clip_poly(spoly, nsv,
446	greg	2.3	(double)x/hres, (x+1.)/hres,
447			(double)y/vres, (y+1.)/vres,
448			ppoly);
449	greg	2.1	if (!npv)
450			continue; /* no overlap */
451			convex_center(ppoly, npv, cxy);
452	greg	2.3	if ((sr.rmax = viewray(sr.rorg,sr.rdir,&ourview,
453			cxy[0],cxy[1])) < -FTINY)
454	greg	2.1	continue; /* not in view */
455	greg	2.3	if (source[sp->sn].sflags & SSPOT &&
456			spotout(&sr, source[sp->sn].sl.s))
457	greg	2.1	continue; /* outside spot */
458	greg	2.16	rayorigin(&sr, SHADOW, NULL, NULL);
459	greg	2.15	sr.rsrc = sp->sn;
460	greg	2.1	rayvalue(&sr); /* compute value */
461	greg	2.22	if (sintens(sr.rcol) <= FTINY)
462	greg	2.1	continue; /* missed/blocked */
463	greg	2.26	if (nc == 3)
464			scolor_rgb(rcol, sr.rcol);
465	greg	2.1	/* modify pixel */
466	greg	2.14	w = poly_area(ppoly, npv) * hres * vres;
467	greg	2.1	if (zbf[y-y0] != NULL &&
468	greg	2.20	sr.rxt < 0.99*zbf[y-y0][x-x0]) {
469			zbf[y-y0][x-x0] = sr.rxt;
470	greg	2.26	} else if (nc == 3) {
471			if (!bigdiff(rcol, pp, 0.07)) {
472			scalecolor(pp, w);
473			continue;
474			}
475			} else if (!sbigsdiff(sr.rcol, pp, 0.07)) {
476	greg	2.23	scalescolor(pp, w);
477	greg	2.13	continue;
478	greg	2.12	}
479	greg	2.26	if (nc == 3) {
480			scalecolor(rcol, w);
481			scalecolor(pp, 1.-w);
482			addcolor(pp, rcol);
483			} else {
484			scalescolor(sr.rcol, w);
485			scalescolor(pp, 1.-w);
486			saddscolor(pp, sr.rcol);
487			}
488	greg	2.1	}
489	greg	2.23	}
490	greg	2.1	}
491			}