src/gen/gensurf.c

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

/* Copyright (c) 1989 Regents of the University of California */

/*
 *  gensurf.c - program to generate functional surfaces
 *
 *      Parametric functions x(s,t), y(s,t) and z(s,t)
 *  specify the surface, which is tesselated into an m by n
 *  array of paired triangles.
 *      The surface normal is defined by the right hand
 *  rule applied to (s,t).
 *
 *      4/3/87
 */

#include  "standard.h"

char  XNAME[] =         "X`SYS`";               /* x function name */
char  YNAME[] =         "Y`SYS`";               /* y function name */
char  ZNAME[] =         "Z`SYS`";               /* z function name */

#define  ABS(x)         ((x)>=0 ? (x) : -(x))

#define  pvect(p)       printf(vformat, (p)[0], (p)[1], (p)[2])

char  vformat[] = "%15.9g %15.9g %15.9g\n";
char  tsargs[] = "4 surf_dx surf_dy surf_dz surf.cal\n";
char  texname[] = "Phong";

int  smooth = 0;                /* apply smoothing? */

char  *modname, *surfname;

                                /* recorded data flags */
#define  HASBORDER      01
#define  TRIPLETS       02
                                /* a data structure */
struct {
        int     flags;                  /* data type */
        short   m, n;                   /* number of s and t values */
        FLOAT   *data;                  /* the data itself, s major sort */
} datarec;                      /* our recorded data */

double  l_hermite(), l_bezier(), l_bspline(), l_dataval();
extern double  funvalue(), argument();

typedef struct {
        FVECT  p;       /* vertex position */
        FVECT  n;       /* average normal */
} POINT;


main(argc, argv)
int  argc;
char  *argv[];
{
        extern long     eclock;
        POINT  *row0, *row1, *row2, *rp;
        int  i, j, m, n;
        char  stmp[256];

        varset("PI", ':', PI);
        funset("hermite", 5, ':', l_hermite);
        funset("bezier", 5, ':', l_bezier);
        funset("bspline", 5, ':', l_bspline);

        if (argc < 8)
                goto userror;

        for (i = 8; i < argc; i++)
                if (!strcmp(argv[i], "-e"))
                        scompile(argv[++i], NULL, 0);
                else if (!strcmp(argv[i], "-f"))
                        fcompile(argv[++i]);
                else if (!strcmp(argv[i], "-s"))
                        smooth++;
                else
                        goto userror;

        modname = argv[1];
        surfname = argv[2];
        m = atoi(argv[6]);
        n = atoi(argv[7]);
        if (m <= 0 || n <= 0)
                goto userror;
        if (!strcmp(argv[5], "-") || access(argv[5], 4) == 0) { /* file? */
                funset(ZNAME, 2, ':', l_dataval);
                if (!strcmp(argv[5],argv[3]) && !strcmp(argv[5],argv[4])) {
                        loaddata(argv[5], m, n, 3);
                        funset(XNAME, 2, ':', l_dataval);
                        funset(YNAME, 2, ':', l_dataval);
                } else {
                        loaddata(argv[5], m, n, 1);
                        sprintf(stmp, "%s(s,t)=%s;", XNAME, argv[3]);
                        scompile(stmp, NULL, 0);
                        sprintf(stmp, "%s(s,t)=%s;", YNAME, argv[4]);
                        scompile(stmp, NULL, 0);
                }
        } else {
                sprintf(stmp, "%s(s,t)=%s;", XNAME, argv[3]);
                scompile(stmp, NULL, 0);
                sprintf(stmp, "%s(s,t)=%s;", YNAME, argv[4]);
                scompile(stmp, NULL, 0);
                sprintf(stmp, "%s(s,t)=%s;", ZNAME, argv[5]);
                scompile(stmp, NULL, 0);
        }
        row0 = (POINT *)malloc((n+3)*sizeof(POINT));
        row1 = (POINT *)malloc((n+3)*sizeof(POINT));
        row2 = (POINT *)malloc((n+3)*sizeof(POINT));
        if (row0 == NULL || row1 == NULL || row2 == NULL) {
                fprintf(stderr, "%s: out of memory\n", argv[0]);
                quit(1);
        }
        row0++; row1++; row2++;
                                                /* print header */
        printhead(argc, argv);
        eclock = 0;
                                                /* initialize */
        comprow(-1.0/m, row0, n);
        comprow(0.0, row1, n);
        comprow(1.0/m, row2, n);
        compnorms(row0, row1, row2, n);
                                                /* for each row */
        for (i = 0; i < m; i++) {
                                                /* compute next row */
                rp = row0;
                row0 = row1;
                row1 = row2;
                row2 = rp;
                comprow((double)(i+2)/m, row2, n);
                compnorms(row0, row1, row2, n);

                for (j = 0; j < n; j++) {
                                                        /* put polygons */
                        if ((i+j) & 1)
                                putsquare(&row0[j], &row1[j],
                                                &row0[j+1], &row1[j+1]);
                        else
                                putsquare(&row1[j], &row1[j+1],
                                                &row0[j], &row0[j+1]);
                }
        }

        quit(0);

userror:
        fprintf(stderr, "Usage: %s material name ", argv[0]);
        fprintf(stderr, "x(s,t) y(s,t) z(s,t) m n [-s][-e expr][-f file]\n");
        quit(1);
}


loaddata(file, m, n, pointsize)         /* load point data from file */
char  *file;
int  m, n;
int  pointsize;
{
        extern char  *fgetword();
        FILE  *fp;
        char  word[64];
        register int  size;
        register FLOAT  *dp;

        datarec.flags = HASBORDER;              /* assume border values */
        datarec.m = m+1;
        datarec.n = n+1;
        size = datarec.m*datarec.n*pointsize;
        if (pointsize == 3)
                datarec.flags |= TRIPLETS;
        dp = (FLOAT *)malloc(size*sizeof(FLOAT));
        if ((datarec.data = dp) == NULL) {
                fputs("Out of memory\n", stderr);
                exit(1);
        }
        if (!strcmp(file, "-")) {
                file = "<stdin>";
                fp = stdin;
        } else if ((fp = fopen(file, "r")) == NULL) {
                fputs(file, stderr);
                fputs(": cannot open\n", stderr);
                exit(1);
        }
        while (size > 0 && fgetword(word, sizeof(word), fp) != NULL) {
                if (!isflt(word)) {
                        fprintf(stderr, "%s: garbled data value: %s\n",
                                        file, word);
                        exit(1);
                }
                *dp++ = atof(word);
                size--;
        }
        if (size == (m+n+1)*pointsize) {        /* no border after all */
                dp = (FLOAT *)realloc((char *)datarec.data,
                                m*n*pointsize*sizeof(FLOAT));
                if (dp != NULL)
                        datarec.data = dp;
                datarec.flags &= ~HASBORDER;
                datarec.m = m;
                datarec.n = n;
                size = 0;
        }
        if (datarec.m < 2 || datarec.n < 2 || size != 0 ||
                        fgetword(word, sizeof(word), fp) != NULL) {
                fputs(file, stderr);
                fputs(": bad number of data points\n", stderr);
                exit(1);
        }
        fclose(fp);
}


double
l_dataval(nam)                          /* return recorded data value */
char  *nam;
{
        double  u, v;
        register int  i, j;
        register FLOAT  *dp;
        double  d00, d01, d10, d11;
                                                /* compute coordinates */
        u = argument(1); v = argument(2);
        if (datarec.flags & HASBORDER) {
                i = u *= datarec.m-1;
                j = v *= datarec.n-1;
        } else {
                i = u = u*datarec.m - .5;
                j = v = v*datarec.n - .5;
        }
        if (i < 0) i = 0;
        else if (i > datarec.m-2) i = datarec.m-2;
        if (j < 0) j = 0;
        else if (j > datarec.n-2) j = datarec.n-2;
                                                /* compute value */
        if (datarec.flags & TRIPLETS) {
                dp = datarec.data + 3*(j*datarec.m + i);
                if (nam == ZNAME)
                        dp += 2;
                else if (nam == YNAME)
                        dp++;
                d00 = dp[0]; d01 = dp[3];
                dp += 3*datarec.m;
                d10 = dp[0]; d11 = dp[3];
        } else {
                dp = datarec.data + j*datarec.m + i;
                d00 = dp[0]; d01 = dp[1];
                dp += datarec.m;
                d10 = dp[0]; d11 = dp[1];
        }
                                                /* bilinear interpolation */
        return((j+1-v)*((i+1-u)*d00+(u-i)*d01)+(v-j)*((i+1-u)*d10+(u-i)*d11));
}


putsquare(p0, p1, p2, p3)               /* put out a square */
POINT  *p0, *p1, *p2, *p3;
{
        static int  nout = 0;
        FVECT  norm[4];
        int  axis;
        FVECT  v1, v2, vc1, vc2;
        int  ok1, ok2;
                                        /* compute exact normals */
        fvsum(v1, p1->p, p0->p, -1.0);
        fvsum(v2, p2->p, p0->p, -1.0);
        fcross(vc1, v1, v2);
        ok1 = normalize(vc1) != 0.0;
        fvsum(v1, p2->p, p3->p, -1.0);
        fvsum(v2, p1->p, p3->p, -1.0);
        fcross(vc2, v1, v2);
        ok2 = normalize(vc2) != 0.0;
        if (!(ok1 | ok2))
                return;
                                        /* compute normal interpolation */
        axis = norminterp(norm, p0, p1, p2, p3);

                                        /* put out quadrilateral? */
        if (ok1 & ok2 && fdot(vc1,vc2) >= 1.0-FTINY*FTINY) {
                printf("\n%s ", modname);
                if (axis != -1) {
                        printf("texfunc %s\n", texname);
                        printf(tsargs);
                        printf("0\n13\t%d\n", axis);
                        pvect(norm[0]);
                        pvect(norm[1]);
                        pvect(norm[2]);
                        fvsum(v1, norm[3], vc1, -0.5);
                        fvsum(v1, v1, vc2, -0.5);
                        pvect(v1);
                        printf("\n%s ", texname);
                }
                printf("polygon %s.%d\n", surfname, ++nout);
                printf("0\n0\n12\n");
                pvect(p0->p);
                pvect(p1->p);
                pvect(p3->p);
                pvect(p2->p);
                return;
        }
                                        /* put out triangles? */
        if (ok1) {
                printf("\n%s ", modname);
                if (axis != -1) {
                        printf("texfunc %s\n", texname);
                        printf(tsargs);
                        printf("0\n13\t%d\n", axis);
                        pvect(norm[0]);
                        pvect(norm[1]);
                        pvect(norm[2]);
                        fvsum(v1, norm[3], vc1, -1.0);
                        pvect(v1);
                        printf("\n%s ", texname);
                }
                printf("polygon %s.%d\n", surfname, ++nout);
                printf("0\n0\n9\n");
                pvect(p0->p);
                pvect(p1->p);
                pvect(p2->p);
        }
        if (ok2) {
                printf("\n%s ", modname);
                if (axis != -1) {
                        printf("texfunc %s\n", texname);
                        printf(tsargs);
                        printf("0\n13\t%d\n", axis);
                        pvect(norm[0]);
                        pvect(norm[1]);
                        pvect(norm[2]);
                        fvsum(v2, norm[3], vc2, -1.0);
                        pvect(v2);
                        printf("\n%s ", texname);
                }
                printf("polygon %s.%d\n", surfname, ++nout);
                printf("0\n0\n9\n");
                pvect(p2->p);
                pvect(p1->p);
                pvect(p3->p);
        }
}


comprow(s, row, siz)                    /* compute row of values */
double  s;
register POINT  *row;
int  siz;
{
        double  st[2];
        int  end;
        register int  i;
        
        if (smooth) {
                i = -1;                 /* compute one past each end */
                end = siz+1;
        } else {
                if (s < -FTINY || s > 1.0+FTINY)
                        return;
                i = 0;
                end = siz;
        }
        st[0] = s;
        while (i <= end) {
                st[1] = (double)i/siz;
                row[i].p[0] = funvalue(XNAME, 2, st);
                row[i].p[1] = funvalue(YNAME, 2, st);
                row[i].p[2] = funvalue(ZNAME, 2, st);
                i++;
        }
}


compnorms(r0, r1, r2, siz)              /* compute row of averaged normals */
register POINT  *r0, *r1, *r2;
int  siz;
{
        FVECT  v1, v2;
        register int  i;

        if (!smooth)                    /* not needed if no smoothing */
                return;
                                        /* compute middle points */
        while (siz-- >= 0) {
                fvsum(v1, r2[0].p, r0[0].p, -1.0);
                fvsum(v2, r1[1].p, r1[-1].p, -1.0);
                fcross(r1[0].n, v1, v2);
                normalize(r1[0].n);
                r0++; r1++; r2++;
        }
}


int
norminterp(resmat, p0, p1, p2, p3)      /* compute normal interpolation */
register FVECT  resmat[4];
POINT  *p0, *p1, *p2, *p3;
{
#define u  ((ax+1)%3)
#define v  ((ax+2)%3)

        register int  ax;
        MAT4  eqnmat;
        FVECT  v1;
        register int  i, j;

        if (!smooth)                    /* no interpolation if no smoothing */
                return(-1);
                                        /* find dominant axis */
        VCOPY(v1, p0->n);
        fvsum(v1, v1, p1->n, 1.0);
        fvsum(v1, v1, p2->n, 1.0);
        fvsum(v1, v1, p3->n, 1.0);
        ax = ABS(v1[0]) > ABS(v1[1]) ? 0 : 1;
        ax = ABS(v1[ax]) > ABS(v1[2]) ? ax : 2;
                                        /* assign equation matrix */
        eqnmat[0][0] = p0->p[u]*p0->p[v];
        eqnmat[0][1] = p0->p[u];
        eqnmat[0][2] = p0->p[v];
        eqnmat[0][3] = 1.0;
        eqnmat[1][0] = p1->p[u]*p1->p[v];
        eqnmat[1][1] = p1->p[u];
        eqnmat[1][2] = p1->p[v];
        eqnmat[1][3] = 1.0;
        eqnmat[2][0] = p2->p[u]*p2->p[v];
        eqnmat[2][1] = p2->p[u];
        eqnmat[2][2] = p2->p[v];
        eqnmat[2][3] = 1.0;
        eqnmat[3][0] = p3->p[u]*p3->p[v];
        eqnmat[3][1] = p3->p[u];
        eqnmat[3][2] = p3->p[v];
        eqnmat[3][3] = 1.0;
                                        /* invert matrix (solve system) */
        if (!invmat(eqnmat, eqnmat))
                return(-1);                     /* no solution */
                                        /* compute result matrix */
        for (j = 0; j < 4; j++)
                for (i = 0; i < 3; i++)
                        resmat[j][i] =  eqnmat[j][0]*p0->n[i] +
                                        eqnmat[j][1]*p1->n[i] +
                                        eqnmat[j][2]*p2->n[i] +
                                        eqnmat[j][3]*p3->n[i];
        return(ax);

#undef u
#undef v
}


/*
 * invmat - computes the inverse of mat into inverse.  Returns 1
 * if there exists an inverse, 0 otherwise.  It uses Gaussian Elimination
 * method.
 */

invmat(inverse,mat)
MAT4  inverse, mat;
{
#define SWAP(a,b,t) (t=a,a=b,b=t)

        MAT4  m4tmp;
        register int i,j,k;
        register double temp;

        copymat4(m4tmp, mat);
                                        /* set inverse to identity */
        for (i = 0; i < 4; i++)
                for (j = 0; j < 4; j++)
                        inverse[i][j] = i==j ? 1.0 : 0.0;

        for(i = 0; i < 4; i++) {
                /* Look for row with largest pivot and swap rows */
                temp = FTINY; j = -1;
                for(k = i; k < 4; k++)
                        if(ABS(m4tmp[k][i]) > temp) {
                                temp = ABS(m4tmp[k][i]);
                                j = k;
                                }
                if(j == -1)     /* No replacing row -> no inverse */
                        return(0);
                if (j != i)
                        for(k = 0; k < 4; k++) {
                                SWAP(m4tmp[i][k],m4tmp[j][k],temp);
                                SWAP(inverse[i][k],inverse[j][k],temp);
                                }

                temp = m4tmp[i][i];
                for(k = 0; k < 4; k++) {
                        m4tmp[i][k] /= temp;
                        inverse[i][k] /= temp;
                        }
                for(j = 0; j < 4; j++) {
                        if(j != i) {
                                temp = m4tmp[j][i];
                                for(k = 0; k < 4; k++) {
                                        m4tmp[j][k] -= m4tmp[i][k]*temp;
                                        inverse[j][k] -= inverse[i][k]*temp;
                                        }
                                }
                        }
                }
        return(1);

#undef SWAP
}


eputs(msg)
char  *msg;
{
        fputs(msg, stderr);
}


wputs(msg)
char  *msg;
{
        eputs(msg);
}


quit(code)
{
        exit(code);
}


printhead(ac, av)               /* print command header */
register int  ac;
register char  **av;
{
        putchar('#');
        while (ac--) {
                putchar(' ');
                fputs(*av++, stdout);
        }
        putchar('\n');
}


double
l_hermite()                     
{
        double  t;
        
        t = argument(5);
        return( argument(1)*((2.0*t-3.0)*t*t+1.0) +
                argument(2)*(-2.0*t+3.0)*t*t +
                argument(3)*((t-2.0)*t+1.0)*t +
                argument(4)*(t-1.0)*t*t );
}


double
l_bezier()
{
        double  t;

        t = argument(5);
        return( argument(1) * (1.+t*(-3.+t*(3.-t))) +
                argument(2) * 3.*t*(1.+t*(-2.+t)) +
                argument(3) * 3.*t*t*(1.-t) +
                argument(4) * t*t*t );
}


double
l_bspline()
{
        double  t;

        t = argument(5);
        return( argument(1) * (1./6.+t*(-1./2.+t*(1./2.-1./6.*t))) +
                argument(2) * (2./3.+t*t*(-1.+1./2.*t)) +
                argument(3) * (1./6.+t*(1./2.+t*(1./2.-1./2.*t))) +
                argument(4) * (1./6.*t*t*t) );
}
Revision:	2.3
Committed:	Wed Feb 5 21:05:00 1992 UTC (32 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.2:	+18 -13 lines
Log Message:	bug fixes
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2			static char SCCSid[] = "$SunId$ LBL";
3			#endif
4	greg	1.2
5	greg	1.7	/* Copyright (c) 1989 Regents of the University of California */
6
7	greg	1.2	/*
8	greg	1.1	* gensurf.c - program to generate functional surfaces
9			*
10			* Parametric functions x(s,t), y(s,t) and z(s,t)
11			* specify the surface, which is tesselated into an m by n
12			* array of paired triangles.
13			* The surface normal is defined by the right hand
14			* rule applied to (s,t).
15			*
16			* 4/3/87
17			*/
18
19	greg	1.5	#include "standard.h"
20	greg	1.1
21	greg	2.2	char XNAME[] = "X`SYS`"; /* x function name */
22			char YNAME[] = "Y`SYS`"; /* y function name */
23			char ZNAME[] = "Z`SYS`"; /* z function name */
24	greg	1.1
25	greg	1.4	#define ABS(x) ((x)>=0 ? (x) : -(x))
26
27	greg	1.3	#define pvect(p) printf(vformat, (p)[0], (p)[1], (p)[2])
28	greg	1.1
29			char vformat[] = "%15.9g %15.9g %15.9g\n";
30	greg	1.3	char tsargs[] = "4 surf_dx surf_dy surf_dz surf.cal\n";
31			char texname[] = "Phong";
32	greg	1.1
33	greg	1.3	int smooth = 0; /* apply smoothing? */
34	greg	1.1
35	greg	1.3	char modname, surfname;
36	greg	1.1
37	greg	2.2	/* recorded data flags */
38			#define HASBORDER 01
39			#define TRIPLETS 02
40			/* a data structure */
41			struct {
42			int flags; /* data type */
43			short m, n; /* number of s and t values */
44			FLOAT data; / the data itself, s major sort */
45			} datarec; /* our recorded data */
46	greg	1.3
47	greg	2.2	double l_hermite(), l_bezier(), l_bspline(), l_dataval();
48			extern double funvalue(), argument();
49
50	greg	1.3	typedef struct {
51			FVECT p; /* vertex position */
52			FVECT n; /* average normal */
53			} POINT;
54
55
56	greg	1.1	main(argc, argv)
57			int argc;
58			char *argv[];
59			{
60	greg	1.9	extern long eclock;
61	greg	1.3	POINT row0, row1, row2, rp;
62	greg	1.1	int i, j, m, n;
63			char stmp[256];
64
65	greg	1.13	varset("PI", ':', PI);
66	greg	1.14	funset("hermite", 5, ':', l_hermite);
67			funset("bezier", 5, ':', l_bezier);
68			funset("bspline", 5, ':', l_bspline);
69	greg	1.1
70			if (argc < 8)
71			goto userror;
72
73			for (i = 8; i < argc; i++)
74			if (!strcmp(argv[i], "-e"))
75	greg	1.10	scompile(argv[++i], NULL, 0);
76	greg	1.1	else if (!strcmp(argv[i], "-f"))
77			fcompile(argv[++i]);
78	greg	1.3	else if (!strcmp(argv[i], "-s"))
79			smooth++;
80	greg	1.1	else
81			goto userror;
82
83	greg	1.3	modname = argv[1];
84			surfname = argv[2];
85	greg	1.1	m = atoi(argv[6]);
86			n = atoi(argv[7]);
87			if (m <= 0 \|\| n <= 0)
88			goto userror;
89	greg	2.2	if (!strcmp(argv[5], "-") \|\| access(argv[5], 4) == 0) { /* file? */
90			funset(ZNAME, 2, ':', l_dataval);
91			if (!strcmp(argv[5],argv[3]) && !strcmp(argv[5],argv[4])) {
92			loaddata(argv[5], m, n, 3);
93			funset(XNAME, 2, ':', l_dataval);
94			funset(YNAME, 2, ':', l_dataval);
95			} else {
96			loaddata(argv[5], m, n, 1);
97			sprintf(stmp, "%s(s,t)=%s;", XNAME, argv[3]);
98			scompile(stmp, NULL, 0);
99			sprintf(stmp, "%s(s,t)=%s;", YNAME, argv[4]);
100			scompile(stmp, NULL, 0);
101			}
102			} else {
103			sprintf(stmp, "%s(s,t)=%s;", XNAME, argv[3]);
104			scompile(stmp, NULL, 0);
105			sprintf(stmp, "%s(s,t)=%s;", YNAME, argv[4]);
106			scompile(stmp, NULL, 0);
107			sprintf(stmp, "%s(s,t)=%s;", ZNAME, argv[5]);
108			scompile(stmp, NULL, 0);
109			}
110	greg	1.4	row0 = (POINT )malloc((n+3)sizeof(POINT));
111			row1 = (POINT )malloc((n+3)sizeof(POINT));
112			row2 = (POINT )malloc((n+3)sizeof(POINT));
113	greg	1.3	if (row0 == NULL \|\| row1 == NULL \|\| row2 == NULL) {
114	greg	1.1	fprintf(stderr, "%s: out of memory\n", argv[0]);
115			quit(1);
116			}
117	greg	1.4	row0++; row1++; row2++;
118	greg	1.3	/* print header */
119	greg	1.1	printhead(argc, argv);
120	greg	1.9	eclock = 0;
121	greg	1.4	/* initialize */
122			comprow(-1.0/m, row0, n);
123	greg	1.3	comprow(0.0, row1, n);
124			comprow(1.0/m, row2, n);
125	greg	1.4	compnorms(row0, row1, row2, n);
126	greg	1.3	/* for each row */
127	greg	1.1	for (i = 0; i < m; i++) {
128			/* compute next row */
129	greg	1.3	rp = row0;
130	greg	1.1	row0 = row1;
131	greg	1.3	row1 = row2;
132			row2 = rp;
133	greg	1.4	comprow((double)(i+2)/m, row2, n);
134			compnorms(row0, row1, row2, n);
135	greg	1.1
136			for (j = 0; j < n; j++) {
137	greg	1.3	/* put polygons */
138			if ((i+j) & 1)
139			putsquare(&row0[j], &row1[j],
140			&row0[j+1], &row1[j+1]);
141			else
142			putsquare(&row1[j], &row1[j+1],
143			&row0[j], &row0[j+1]);
144	greg	1.1	}
145			}
146
147			quit(0);
148
149			userror:
150			fprintf(stderr, "Usage: %s material name ", argv[0]);
151	greg	1.3	fprintf(stderr, "x(s,t) y(s,t) z(s,t) m n [-s][-e expr][-f file]\n");
152	greg	1.1	quit(1);
153	greg	2.2	}
154
155
156			loaddata(file, m, n, pointsize) /* load point data from file */
157			char *file;
158			int m, n;
159			int pointsize;
160			{
161			extern char *fgetword();
162			FILE *fp;
163			char word[64];
164			register int size;
165			register FLOAT *dp;
166
167			datarec.flags = HASBORDER; /* assume border values */
168	greg	2.3	datarec.m = m+1;
169			datarec.n = n+1;
170			size = datarec.mdatarec.npointsize;
171	greg	2.2	if (pointsize == 3)
172			datarec.flags \|= TRIPLETS;
173			dp = (FLOAT )malloc(sizesizeof(FLOAT));
174			if ((datarec.data = dp) == NULL) {
175			fputs("Out of memory\n", stderr);
176			exit(1);
177			}
178			if (!strcmp(file, "-")) {
179			file = "<stdin>";
180			fp = stdin;
181			} else if ((fp = fopen(file, "r")) == NULL) {
182			fputs(file, stderr);
183			fputs(": cannot open\n", stderr);
184			exit(1);
185			}
186			while (size > 0 && fgetword(word, sizeof(word), fp) != NULL) {
187			if (!isflt(word)) {
188			fprintf(stderr, "%s: garbled data value: %s\n",
189			file, word);
190			exit(1);
191			}
192			*dp++ = atof(word);
193			size--;
194			}
195			if (size == (m+n+1)pointsize) { / no border after all */
196			dp = (FLOAT )realloc((char )datarec.data,
197			mnpointsize*sizeof(FLOAT));
198			if (dp != NULL)
199			datarec.data = dp;
200			datarec.flags &= ~HASBORDER;
201	greg	2.3	datarec.m = m;
202			datarec.n = n;
203	greg	2.2	size = 0;
204			}
205	greg	2.3	if (datarec.m < 2 \|\| datarec.n < 2 \|\| size != 0 \|\|
206			fgetword(word, sizeof(word), fp) != NULL) {
207	greg	2.2	fputs(file, stderr);
208			fputs(": bad number of data points\n", stderr);
209			exit(1);
210			}
211			fclose(fp);
212			}
213
214
215			double
216			l_dataval(nam) /* return recorded data value */
217			char *nam;
218			{
219			double u, v;
220			register int i, j;
221			register FLOAT *dp;
222			double d00, d01, d10, d11;
223			/* compute coordinates */
224			u = argument(1); v = argument(2);
225			if (datarec.flags & HASBORDER) {
226	greg	2.3	i = u *= datarec.m-1;
227			j = v *= datarec.n-1;
228	greg	2.2	} else {
229	greg	2.3	i = u = u*datarec.m - .5;
230			j = v = v*datarec.n - .5;
231	greg	2.2	}
232			if (i < 0) i = 0;
233			else if (i > datarec.m-2) i = datarec.m-2;
234			if (j < 0) j = 0;
235			else if (j > datarec.n-2) j = datarec.n-2;
236			/* compute value */
237			if (datarec.flags & TRIPLETS) {
238	greg	2.3	dp = datarec.data + 3(jdatarec.m + i);
239			if (nam == ZNAME)
240			dp += 2;
241			else if (nam == YNAME)
242	greg	2.2	dp++;
243			d00 = dp[0]; d01 = dp[3];
244	greg	2.3	dp += 3*datarec.m;
245	greg	2.2	d10 = dp[0]; d11 = dp[3];
246			} else {
247	greg	2.3	dp = datarec.data + j*datarec.m + i;
248	greg	2.2	d00 = dp[0]; d01 = dp[1];
249	greg	2.3	dp += datarec.m;
250	greg	2.2	d10 = dp[0]; d11 = dp[1];
251			}
252			/* bilinear interpolation */
253			return((j+1-v)((i+1-u)d00+(u-i)d01)+(v-j)((i+1-u)d10+(u-i)d11));
254	greg	1.1	}
255
256
257	greg	1.3	putsquare(p0, p1, p2, p3) /* put out a square */
258			POINT p0, p1, p2, p3;
259			{
260			static int nout = 0;
261			FVECT norm[4];
262			int axis;
263			FVECT v1, v2, vc1, vc2;
264			int ok1, ok2;
265			/* compute exact normals */
266			fvsum(v1, p1->p, p0->p, -1.0);
267			fvsum(v2, p2->p, p0->p, -1.0);
268			fcross(vc1, v1, v2);
269			ok1 = normalize(vc1) != 0.0;
270			fvsum(v1, p2->p, p3->p, -1.0);
271			fvsum(v2, p1->p, p3->p, -1.0);
272			fcross(vc2, v1, v2);
273			ok2 = normalize(vc2) != 0.0;
274			if (!(ok1 \| ok2))
275			return;
276			/* compute normal interpolation */
277			axis = norminterp(norm, p0, p1, p2, p3);
278
279			/* put out quadrilateral? */
280			if (ok1 & ok2 && fdot(vc1,vc2) >= 1.0-FTINY*FTINY) {
281			printf("\n%s ", modname);
282			if (axis != -1) {
283			printf("texfunc %s\n", texname);
284			printf(tsargs);
285			printf("0\n13\t%d\n", axis);
286			pvect(norm[0]);
287			pvect(norm[1]);
288			pvect(norm[2]);
289			fvsum(v1, norm[3], vc1, -0.5);
290			fvsum(v1, v1, vc2, -0.5);
291			pvect(v1);
292			printf("\n%s ", texname);
293			}
294			printf("polygon %s.%d\n", surfname, ++nout);
295			printf("0\n0\n12\n");
296			pvect(p0->p);
297			pvect(p1->p);
298			pvect(p3->p);
299			pvect(p2->p);
300			return;
301			}
302			/* put out triangles? */
303			if (ok1) {
304			printf("\n%s ", modname);
305			if (axis != -1) {
306			printf("texfunc %s\n", texname);
307			printf(tsargs);
308			printf("0\n13\t%d\n", axis);
309			pvect(norm[0]);
310			pvect(norm[1]);
311			pvect(norm[2]);
312			fvsum(v1, norm[3], vc1, -1.0);
313			pvect(v1);
314			printf("\n%s ", texname);
315			}
316			printf("polygon %s.%d\n", surfname, ++nout);
317			printf("0\n0\n9\n");
318			pvect(p0->p);
319			pvect(p1->p);
320			pvect(p2->p);
321			}
322			if (ok2) {
323			printf("\n%s ", modname);
324			if (axis != -1) {
325			printf("texfunc %s\n", texname);
326			printf(tsargs);
327			printf("0\n13\t%d\n", axis);
328			pvect(norm[0]);
329			pvect(norm[1]);
330			pvect(norm[2]);
331			fvsum(v2, norm[3], vc2, -1.0);
332			pvect(v2);
333			printf("\n%s ", texname);
334			}
335			printf("polygon %s.%d\n", surfname, ++nout);
336			printf("0\n0\n9\n");
337			pvect(p2->p);
338			pvect(p1->p);
339			pvect(p3->p);
340			}
341			}
342
343
344	greg	1.1	comprow(s, row, siz) /* compute row of values */
345			double s;
346	greg	1.3	register POINT *row;
347	greg	1.1	int siz;
348			{
349	greg	1.4	double st[2];
350	greg	1.8	int end;
351	greg	1.4	register int i;
352	greg	1.8
353			if (smooth) {
354			i = -1; /* compute one past each end */
355			end = siz+1;
356			} else {
357			if (s < -FTINY \|\| s > 1.0+FTINY)
358			return;
359			i = 0;
360			end = siz;
361			}
362	greg	1.1	st[0] = s;
363	greg	1.8	while (i <= end) {
364	greg	1.4	st[1] = (double)i/siz;
365			row[i].p[0] = funvalue(XNAME, 2, st);
366			row[i].p[1] = funvalue(YNAME, 2, st);
367			row[i].p[2] = funvalue(ZNAME, 2, st);
368	greg	1.8	i++;
369	greg	1.1	}
370	greg	1.3	}
371
372
373			compnorms(r0, r1, r2, siz) /* compute row of averaged normals */
374			register POINT r0, r1, *r2;
375			int siz;
376			{
377	greg	1.11	FVECT v1, v2;
378	greg	1.4	register int i;
379	greg	1.3
380			if (!smooth) /* not needed if no smoothing */
381			return;
382			/* compute middle points */
383	greg	1.4	while (siz-- >= 0) {
384	greg	1.11	fvsum(v1, r2[0].p, r0[0].p, -1.0);
385			fvsum(v2, r1[1].p, r1[-1].p, -1.0);
386	greg	1.3	fcross(r1[0].n, v1, v2);
387			normalize(r1[0].n);
388			r0++; r1++; r2++;
389			}
390			}
391
392
393			int
394			norminterp(resmat, p0, p1, p2, p3) /* compute normal interpolation */
395			register FVECT resmat[4];
396			POINT p0, p1, p2, p3;
397			{
398			#define u ((ax+1)%3)
399			#define v ((ax+2)%3)
400
401			register int ax;
402	greg	1.12	MAT4 eqnmat;
403	greg	1.3	FVECT v1;
404			register int i, j;
405
406			if (!smooth) /* no interpolation if no smoothing */
407			return(-1);
408			/* find dominant axis */
409			VCOPY(v1, p0->n);
410			fvsum(v1, v1, p1->n, 1.0);
411			fvsum(v1, v1, p2->n, 1.0);
412			fvsum(v1, v1, p3->n, 1.0);
413	greg	1.4	ax = ABS(v1[0]) > ABS(v1[1]) ? 0 : 1;
414			ax = ABS(v1[ax]) > ABS(v1[2]) ? ax : 2;
415	greg	1.3	/* assign equation matrix */
416			eqnmat[0][0] = p0->p[u]*p0->p[v];
417			eqnmat[0][1] = p0->p[u];
418			eqnmat[0][2] = p0->p[v];
419			eqnmat[0][3] = 1.0;
420			eqnmat[1][0] = p1->p[u]*p1->p[v];
421			eqnmat[1][1] = p1->p[u];
422			eqnmat[1][2] = p1->p[v];
423			eqnmat[1][3] = 1.0;
424			eqnmat[2][0] = p2->p[u]*p2->p[v];
425			eqnmat[2][1] = p2->p[u];
426			eqnmat[2][2] = p2->p[v];
427			eqnmat[2][3] = 1.0;
428			eqnmat[3][0] = p3->p[u]*p3->p[v];
429			eqnmat[3][1] = p3->p[u];
430			eqnmat[3][2] = p3->p[v];
431			eqnmat[3][3] = 1.0;
432			/* invert matrix (solve system) */
433	greg	1.4	if (!invmat(eqnmat, eqnmat))
434	greg	1.3	return(-1); /* no solution */
435			/* compute result matrix */
436			for (j = 0; j < 4; j++)
437			for (i = 0; i < 3; i++)
438	greg	1.4	resmat[j][i] = eqnmat[j][0]*p0->n[i] +
439			eqnmat[j][1]*p1->n[i] +
440			eqnmat[j][2]*p2->n[i] +
441			eqnmat[j][3]*p3->n[i];
442	greg	1.3	return(ax);
443
444			#undef u
445			#undef v
446			}
447
448
449			/*
450			* invmat - computes the inverse of mat into inverse. Returns 1
451			* if there exists an inverse, 0 otherwise. It uses Gaussian Elimination
452			* method.
453			*/
454
455			invmat(inverse,mat)
456	greg	1.12	MAT4 inverse, mat;
457	greg	1.3	{
458			#define SWAP(a,b,t) (t=a,a=b,b=t)
459
460	greg	1.12	MAT4 m4tmp;
461	greg	1.3	register int i,j,k;
462			register double temp;
463
464	greg	1.12	copymat4(m4tmp, mat);
465	greg	1.4	/* set inverse to identity */
466			for (i = 0; i < 4; i++)
467			for (j = 0; j < 4; j++)
468			inverse[i][j] = i==j ? 1.0 : 0.0;
469	greg	1.3
470			for(i = 0; i < 4; i++) {
471	greg	1.11	/* Look for row with largest pivot and swap rows */
472	greg	1.4	temp = FTINY; j = -1;
473			for(k = i; k < 4; k++)
474			if(ABS(m4tmp[k][i]) > temp) {
475			temp = ABS(m4tmp[k][i]);
476			j = k;
477			}
478	greg	1.11	if(j == -1) /* No replacing row -> no inverse */
479	greg	1.4	return(0);
480			if (j != i)
481			for(k = 0; k < 4; k++) {
482			SWAP(m4tmp[i][k],m4tmp[j][k],temp);
483			SWAP(inverse[i][k],inverse[j][k],temp);
484			}
485	greg	1.3
486			temp = m4tmp[i][i];
487			for(k = 0; k < 4; k++) {
488			m4tmp[i][k] /= temp;
489			inverse[i][k] /= temp;
490			}
491			for(j = 0; j < 4; j++) {
492			if(j != i) {
493			temp = m4tmp[j][i];
494			for(k = 0; k < 4; k++) {
495			m4tmp[j][k] -= m4tmp[i][k]*temp;
496			inverse[j][k] -= inverse[i][k]*temp;
497			}
498			}
499			}
500			}
501			return(1);
502	greg	1.4
503	greg	1.3	#undef SWAP
504	greg	1.1	}
505
506
507			eputs(msg)
508			char *msg;
509			{
510			fputs(msg, stderr);
511			}
512
513
514			wputs(msg)
515			char *msg;
516			{
517			eputs(msg);
518			}
519
520
521			quit(code)
522			{
523			exit(code);
524			}
525
526
527			printhead(ac, av) /* print command header */
528			register int ac;
529			register char **av;
530			{
531			putchar('#');
532			while (ac--) {
533			putchar(' ');
534			fputs(*av++, stdout);
535			}
536			putchar('\n');
537			}
538
539
540			double
541			l_hermite()
542			{
543			double t;
544
545			t = argument(5);
546			return( argument(1)((2.0t-3.0)tt+1.0) +
547			argument(2)(-2.0t+3.0)tt +
548			argument(3)((t-2.0)t+1.0)*t +
549			argument(4)(t-1.0)t*t );
550	greg	1.6	}
551
552
553			double
554			l_bezier()
555			{
556			double t;
557
558			t = argument(5);
559			return( argument(1) * (1.+t(-3.+t(3.-t))) +
560			argument(2) * 3.t(1.+t*(-2.+t)) +
561			argument(3) * 3.tt*(1.-t) +
562			argument(4) * ttt );
563	greg	1.7	}
564
565
566			double
567			l_bspline()
568			{
569			double t;
570
571			t = argument(5);
572			return( argument(1) * (1./6.+t(-1./2.+t(1./2.-1./6.*t))) +
573			argument(2) * (2./3.+tt(-1.+1./2.*t)) +
574			argument(3) * (1./6.+t(1./2.+t(1./2.-1./2.*t))) +
575			argument(4) * (1./6.tt*t) );
576	greg	1.1	}