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GENSURF.C
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C/C++ Source or Header
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1993-10-07
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13KB
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577 lines
#ifndef lint
static char SCCSid[] = "@(#)gensurf.c 2.3 2/5/92 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) );
}