src/rt/srcdraw.c

#ifndef lint
static const char       RCSid[] = "$Id: srcdraw.c,v 2.8 2003/07/27 22:12:03 schorsch 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  "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(p, cv, crit)                   /* 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
clipregion(a, b, cv, crit, r)           /* find intersection with boundary */
register RREAL  a[2], 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(vl, nv, cv, crit, vlo)     /* 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(vl, nv, xl, xr, yb, ya, vlo)      /* clip polygon to box */
RREAL   vl[MAXVERT][2];
int     nv;
double  xl, xr, yb, 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(vl, nv, ar2)                      /* 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
convex_center(vl, nv, cv)               /* 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(vl, nv)                       /* 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(vl, nv, vlo)                /* 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
spinsert(sn, vl, nv)                    /* 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;
}


int
sourcepoly(sn, sp)                      /* 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 && ourview.type == VT_PAR)
                        return(0);              /* all or nothing case */
                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 */
init_drawsources(rad)
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--; ) {
                                        /* 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(pic, zbf, x0, xsiz, y0, ysiz)
COLOR   *pic[];                         /* subimage pixel value array */
float   *zbf[];                         /* subimage distance array (opt.) */
int     x0, xsiz, y0, ysiz;             /* origin and size of subimage */
{
        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 */
                                w = poly_area(ppoly, npv) * hres * vres;
                                if (w < .95) {          /* subpixel source */
                                        rayorigin(&sr, NULL, SHADOW, 1.0);
                                        sr.rsrc = sp->sn;
                                } else
                                        rayorigin(&sr, NULL, PRIMARY, 1.0);
                                rayvalue(&sr);          /* compute value */
                                if (bright(sr.rcol) <= FTINY)
                                        continue;       /* missed/blocked */
                                                        /* modify pixel */
                                if (zbf[y-y0] != NULL &&
                                                sr.rt < 0.999*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 */
                                        setcolor(pic[y-y0][x-x0], 0., 0., 0.);
                                scalecolor(sr.rcol, w);
                                scalecolor(pic[y-y0][x-x0], 1.-w);
                                addcolor(pic[y-y0][x-x0], sr.rcol);
                        }
        }
}
Revision:	2.9
Committed:	Wed Oct 1 22:07:19 2003 UTC (20 years, 7 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.8:	+9 -6 lines
Log Message:	Fixed old problem with drawsources and illum's
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.9	static const char RCSid[] = "$Id: srcdraw.c,v 2.8 2003/07/27 22:12:03 schorsch 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
14			#include "view.h"
15
16			#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
38	greg	2.1	static int
39			inregion(p, cv, crit) /* check if vertex is in region */
40	schorsch	2.7	RREAL p[2];
41	greg	2.1	double cv;
42			int crit;
43			{
44			switch (crit) {
45			case CLIP_ABOVE:
46			return(p[1] < cv);
47			case CLIP_BELOW:
48			return(p[1] >= cv);
49			case CLIP_RIGHT:
50			return(p[0] < cv);
51			case CLIP_LEFT:
52			return(p[0] >= cv);
53			}
54			return(-1);
55			}
56
57
58			static
59			clipregion(a, b, cv, crit, r) /* find intersection with boundary */
60	schorsch	2.7	register RREAL a[2], b[2];
61	greg	2.1	double cv;
62			int crit;
63	schorsch	2.7	RREAL r[2]; /* return value */
64	greg	2.1	{
65			switch (crit) {
66			case CLIP_ABOVE:
67			case CLIP_BELOW:
68			r[1] = cv;
69			r[0] = a[0] + (cv-a[1])/(b[1]-a[1])*(b[0]-a[0]);
70			return;
71			case CLIP_RIGHT:
72			case CLIP_LEFT:
73			r[0] = cv;
74			r[1] = a[1] + (cv-a[0])/(b[0]-a[0])*(b[1]-a[1]);
75			return;
76			}
77			}
78
79
80			static int
81			hp_clip_poly(vl, nv, cv, crit, vlo) /* clip polygon to half-plane */
82	schorsch	2.7	RREAL vl[][2];
83	greg	2.1	int nv;
84			double cv;
85			int crit;
86	schorsch	2.7	RREAL vlo[][2]; /* return value */
87	greg	2.1	{
88	schorsch	2.7	RREAL s, p;
89	greg	2.1	register int j, nvo;
90
91			s = vl[nv-1];
92			nvo = 0;
93			for (j = 0; j < nv; j++) {
94			p = vl[j];
95			if (inregion(p, cv, crit)) {
96			if (!inregion(s, cv, crit))
97			clipregion(s, p, cv, crit, vlo[nvo++]);
98			vlo[nvo][0] = p[0]; vlo[nvo++][1] = p[1];
99			} else if (inregion(s, cv, crit))
100			clipregion(s, p, cv, crit, vlo[nvo++]);
101			s = p;
102			}
103			return(nvo);
104			}
105
106
107			static int
108			box_clip_poly(vl, nv, xl, xr, yb, ya, vlo) /* clip polygon to box */
109	schorsch	2.7	RREAL vl[MAXVERT][2];
110	greg	2.1	int nv;
111			double xl, xr, yb, ya;
112	schorsch	2.7	RREAL vlo[MAXVERT][2]; /* return value */
113	greg	2.1	{
114	schorsch	2.7	RREAL vlt[MAXVERT][2];
115	greg	2.1	int nvt, nvo;
116
117			nvt = hp_clip_poly(vl, nv, yb, CLIP_BELOW, vlt);
118			nvo = hp_clip_poly(vlt, nvt, ya, CLIP_ABOVE, vlo);
119			nvt = hp_clip_poly(vlo, nvo, xl, CLIP_LEFT, vlt);
120			nvo = hp_clip_poly(vlt, nvt, xr, CLIP_RIGHT, vlo);
121
122			return(nvo);
123			}
124
125
126			static double
127			minw2(vl, nv, ar2) /* compute square of minimum width */
128	schorsch	2.7	RREAL vl[][2];
129	greg	2.1	int nv;
130			double ar2;
131			{
132			double d2, w2, w2min, w2max;
133	schorsch	2.7	register RREAL p0, p1, *p2;
134	greg	2.1	int i, j;
135			/* find minimum for all widths */
136			w2min = FHUGE;
137			p0 = vl[nv-1];
138			for (i = 0; i < nv; i++) { /* for each edge */
139			p1 = vl[i];
140			d2 = (p1[0]-p0[0])*(p1[0]-p0[0]) +
141			(p1[1]-p0[1])(p1[1]-p0[1])ar2;
142			w2max = 0.; /* find maximum for this side */
143			for (j = 1; j < nv-1; j++) {
144			p2 = vl[(i+j)%nv];
145			w2 = (p1[0]-p0[0])*(p2[1]-p0[1]) -
146			(p1[1]-p0[1])*(p2[0]-p0[0]);
147			w2 = w2w2ar2/d2; /* triangle height squared */
148			if (w2 > w2max)
149			w2max = w2;
150			}
151			if (w2max < w2min) /* global min. based on local max.'s */
152			w2min = w2max;
153			p0 = p1;
154			}
155			return(w2min);
156			}
157
158
159			static
160			convex_center(vl, nv, cv) /* compute center of convex polygon */
161	schorsch	2.7	register RREAL vl[][2];
162	greg	2.1	int nv;
163	schorsch	2.7	RREAL cv[2]; /* return value */
164	greg	2.1	{
165			register int i;
166			/* simple average (suboptimal) */
167			cv[0] = cv[1] = 0.;
168			for (i = 0; i < nv; i++) {
169			cv[0] += vl[i][0];
170			cv[1] += vl[i][1];
171			}
172			cv[0] /= (double)nv;
173			cv[1] /= (double)nv;
174			}
175
176
177			static double
178			poly_area(vl, nv) /* compute area of polygon */
179	schorsch	2.7	register RREAL vl[][2];
180	greg	2.1	int nv;
181			{
182			double a;
183	schorsch	2.7	RREAL v0[2], v1[2];
184	greg	2.1	register int i;
185
186			a = 0.;
187			v0[0] = vl[1][0] - vl[0][0];
188			v0[1] = vl[1][1] - vl[0][1];
189			for (i = 2; i < nv; i++) {
190			v1[0] = vl[i][0] - vl[0][0];
191			v1[1] = vl[i][1] - vl[0][1];
192			a += v0[0]v1[1] - v0[1]v1[0];
193			v0[0] = v1[0]; v0[1] = v1[1];
194			}
195			return(a * (a >= 0. ? .5 : -.5));
196			}
197
198
199			static int
200			convex_hull(vl, nv, vlo) /* compute polygon's convex hull */
201	schorsch	2.7	RREAL vl[][2];
202	greg	2.1	int nv;
203	schorsch	2.7	RREAL vlo[][2]; /* return value */
204	greg	2.1	{
205			int nvo, nvt;
206	schorsch	2.7	RREAL vlt[MAXVERT][2];
207	greg	2.1	double voa, vta;
208			register int i, j;
209			/* start with original polygon */
210			for (i = nvo = nv; i--; ) {
211			vlo[i][0] = vl[i][0]; vlo[i][1] = vl[i][1];
212			}
213			voa = poly_area(vlo, nvo); /* compute its area */
214			for (i = 0; i < nvo; i++) { /* for each output vertex */
215			for (j = 0; j < i; j++) {
216			vlt[j][0] = vlo[j][0]; vlt[j][1] = vlo[j][1];
217			}
218			nvt = nvo - 1; /* make poly w/o vertex */
219			for (j = i; j < nvt; j++) {
220			vlt[j][0] = vlo[j+1][0]; vlt[j][1] = vlo[j+1][1];
221			}
222			vta = poly_area(vlt, nvt);
223			if (vta >= voa) { /* is simpler poly bigger? */
224			voa = vta; /* then use it */
225			for (j = nvo = nvt; j--; ) {
226			vlo[j][0] = vlt[j][0]; vlo[j][1] = vlt[j][1];
227			}
228			i--; /* next adjust */
229			}
230			}
231			return(nvo);
232			}
233
234
235	greg	2.3	static
236			spinsert(sn, vl, nv) /* insert new source polygon */
237			int sn;
238	schorsch	2.7	RREAL vl[][2];
239	greg	2.3	int nv;
240			{
241			register SPLIST *spn;
242			register int i;
243
244			if (nv < 3)
245			return;
246			if (nv > 3)
247	schorsch	2.7	spn = (SPLIST )malloc(sizeof(SPLIST)+sizeof(RREAL)2*(nv-3));
248	greg	2.3	else
249			spn = (SPLIST *)malloc(sizeof(SPLIST));
250			if (spn == NULL)
251			error(SYSTEM, "out of memory in spinsert");
252			spn->sn = sn;
253			for (i = spn->nv = nv; i--; ) {
254			spn->vl[i][0] = vl[i][0]; spn->vl[i][1] = vl[i][1];
255			}
256			spn->next = sphead; /* push onto global list */
257			sphead = spn;
258			}
259
260
261	greg	2.1	int
262	greg	2.3	sourcepoly(sn, sp) /* compute image polygon for source */
263	greg	2.1	int sn;
264	schorsch	2.7	RREAL sp[MAXVERT][2];
265	greg	2.1	{
266	greg	2.9	static short cubeord[8][6] = {{1,3,2,6,4,5},{0,4,5,7,3,2},
267	greg	2.1	{0,1,3,7,6,4},{0,1,5,7,6,2},
268			{0,2,6,7,5,1},{0,4,6,7,3,1},
269			{0,2,3,7,5,4},{1,5,4,6,2,3}};
270			register SRCREC *s = source + sn;
271			FVECT ap, ip;
272	schorsch	2.7	RREAL pt[6][2];
273	greg	2.1	int dir;
274			register int i, j;
275
276			if (s->sflags & (SDISTANT\|SFLAT)) {
277	greg	2.3	if (s->sflags & SDISTANT && ourview.type == VT_PAR)
278	greg	2.1	return(0); /* all or nothing case */
279			if (s->sflags & SFLAT) {
280			for (i = 0; i < 3; i++)
281	greg	2.3	ap[i] = s->sloc[i] - ourview.vp[i];
282	greg	2.1	if (DOT(ap, s->snorm) >= 0.)
283			return(0); /* source faces away */
284			}
285			for (j = 0; j < 4; j++) { /* four corners */
286			for (i = 0; i < 3; i++) {
287			ap[i] = s->sloc[i];
288	schorsch	2.8	if ((j==1)\|(j==2)) ap[i] += s->ss[SU][i];
289	greg	2.1	else ap[i] -= s->ss[SU][i];
290	schorsch	2.8	if ((j==2)\|(j==3)) ap[i] += s->ss[SV][i];
291	greg	2.1	else ap[i] -= s->ss[SV][i];
292			if (s->sflags & SDISTANT) {
293	greg	2.3	ap[i] *= 1. + ourview.vfore;
294			ap[i] += ourview.vp[i];
295	greg	2.1	}
296			}
297	greg	2.3	viewloc(ip, &ourview, ap); /* find image point */
298	greg	2.1	if (ip[2] <= 0.)
299			return(0); /* in front of view */
300			sp[j][0] = ip[0]; sp[j][1] = ip[1];
301			}
302			return(4);
303			}
304			/* identify furthest corner */
305			for (i = 0; i < 3; i++)
306	greg	2.3	ap[i] = s->sloc[i] - ourview.vp[i];
307	greg	2.1	dir = (DOT(ap,s->ss[SU])>0.) \|
308			(DOT(ap,s->ss[SV])>0.)<<1 \|
309			(DOT(ap,s->ss[SW])>0.)<<2 ;
310			/* order vertices based on this */
311			for (j = 0; j < 6; j++) {
312			for (i = 0; i < 3; i++) {
313			ap[i] = s->sloc[i];
314			if (cubeord[dir][j] & 1) ap[i] += s->ss[SU][i];
315			else ap[i] -= s->ss[SU][i];
316			if (cubeord[dir][j] & 2) ap[i] += s->ss[SV][i];
317			else ap[i] -= s->ss[SV][i];
318			if (cubeord[dir][j] & 4) ap[i] += s->ss[SW][i];
319			else ap[i] -= s->ss[SW][i];
320			}
321	greg	2.3	viewloc(ip, &ourview, ap); /* find image point */
322	greg	2.1	if (ip[2] <= 0.)
323			return(0); /* in front of view */
324			pt[j][0] = ip[0]; pt[j][1] = ip[1];
325			}
326			return(convex_hull(pt, 6, sp)); /* make sure it's convex */
327			}
328
329
330	greg	2.3	/* initialize by finding sources smaller than rad */
331			init_drawsources(rad)
332			int rad; /* source sample size */
333			{
334	schorsch	2.7	RREAL spoly[MAXVERT][2];
335	greg	2.3	int nsv;
336			register SPLIST *sp;
337			register int i;
338			/* free old source list if one */
339			for (sp = sphead; sp != NULL; sp = sphead) {
340			sphead = sp->next;
341	greg	2.5	free((void *)sp);
342	greg	2.3	}
343			/* loop through all sources */
344			for (i = nsources; i--; ) {
345			/* compute image polygon for source */
346			if (!(nsv = sourcepoly(i, spoly)))
347			continue;
348			/* clip to image boundaries */
349			if (!(nsv = box_clip_poly(spoly, nsv, 0., 1., 0., 1., spoly)))
350			continue;
351			/* big enough for standard sampling? */
352			if (minw2(spoly, nsv, ourview.vn2/ourview.hn2) >
353			(double)rad*rad/hres/hres)
354			continue;
355			/* OK, add to our list */
356			spinsert(i, spoly, nsv);
357			}
358			}
359
360	greg	2.5	void /* add sources smaller than rad to computed subimage */
361	greg	2.3	drawsources(pic, zbf, x0, xsiz, y0, ysiz)
362	greg	2.1	COLOR pic[]; / subimage pixel value array */
363			float zbf[]; / subimage distance array (opt.) */
364			int x0, xsiz, y0, ysiz; /* origin and size of subimage */
365			{
366	schorsch	2.7	RREAL spoly[MAXVERT][2], ppoly[MAXVERT][2];
367	greg	2.1	int nsv, npv;
368	greg	2.3	int xmin, xmax, ymin, ymax, x, y;
369	schorsch	2.7	RREAL cxy[2];
370	gregl	2.4	double w;
371	greg	2.1	RAY sr;
372	greg	2.3	register SPLIST *sp;
373			register int i;
374			/* check each source in our list */
375			for (sp = sphead; sp != NULL; sp = sp->next) {
376	greg	2.1	/* clip source poly to subimage */
377	greg	2.3	nsv = box_clip_poly(sp->vl, sp->nv,
378			(double)x0/hres, (double)(x0+xsiz)/hres,
379			(double)y0/vres, (double)(y0+ysiz)/vres, spoly);
380	greg	2.1	if (!nsv)
381			continue;
382			/* find common subimage (BBox) */
383			xmin = x0 + xsiz; xmax = x0;
384			ymin = y0 + ysiz; ymax = y0;
385			for (i = 0; i < nsv; i++) {
386	greg	2.3	if ((double)xmin/hres > spoly[i][0])
387			xmin = spoly[i][0]*hres + FTINY;
388			if ((double)xmax/hres < spoly[i][0])
389			xmax = spoly[i][0]*hres - FTINY;
390			if ((double)ymin/vres > spoly[i][1])
391			ymin = spoly[i][1]*vres + FTINY;
392			if ((double)ymax/vres < spoly[i][1])
393			ymax = spoly[i][1]*vres - FTINY;
394	greg	2.1	}
395			/* evaluate each pixel in BBox */
396			for (y = ymin; y <= ymax; y++)
397			for (x = xmin; x <= xmax; x++) {
398			/* subarea for pixel */
399			npv = box_clip_poly(spoly, nsv,
400	greg	2.3	(double)x/hres, (x+1.)/hres,
401			(double)y/vres, (y+1.)/vres,
402			ppoly);
403	greg	2.1	if (!npv)
404			continue; /* no overlap */
405			convex_center(ppoly, npv, cxy);
406	greg	2.3	if ((sr.rmax = viewray(sr.rorg,sr.rdir,&ourview,
407			cxy[0],cxy[1])) < -FTINY)
408	greg	2.1	continue; /* not in view */
409	greg	2.3	if (source[sp->sn].sflags & SSPOT &&
410			spotout(&sr, source[sp->sn].sl.s))
411	greg	2.1	continue; /* outside spot */
412	greg	2.9	w = poly_area(ppoly, npv) * hres * vres;
413			if (w < .95) { /* subpixel source */
414			rayorigin(&sr, NULL, SHADOW, 1.0);
415			sr.rsrc = sp->sn;
416			} else
417			rayorigin(&sr, NULL, PRIMARY, 1.0);
418	greg	2.1	rayvalue(&sr); /* compute value */
419			if (bright(sr.rcol) <= FTINY)
420			continue; /* missed/blocked */
421			/* modify pixel */
422			if (zbf[y-y0] != NULL &&
423	gregl	2.4	sr.rt < 0.999*zbf[y-y0][x-x0])
424	greg	2.1	zbf[y-y0][x-x0] = sr.rt;
425	gregl	2.4	else if (!bigdiff(sr.rcol, pic[y-y0][x-x0],
426	greg	2.9	0.01)) /* source sample */
427	gregl	2.4	setcolor(pic[y-y0][x-x0], 0., 0., 0.);
428			scalecolor(sr.rcol, w);
429			scalecolor(pic[y-y0][x-x0], 1.-w);
430	greg	2.1	addcolor(pic[y-y0][x-x0], sr.rcol);
431			}
432			}
433			}