static int
puttri( /* convert a triangle */
char *v1,
char *v2,
char *v3
)
{
VNDX v1i, v2i, v3i;
RREAL *v1c, *v2c, *v3c;
RREAL *v1n, *v2n, *v3n;
if (!cvtndx(v1i, v1) || !cvtndx(v2i, v2) || !cvtndx(v3i, v3)) {
error(WARNING, "bad vertex reference");
return(0);
}
if (v1i[1]>=0 && v2i[1]>=0 && v3i[1]>=0) {
v1c = vtlist[v1i[1]];
v2c = vtlist[v2i[1]];
v3c = vtlist[v3i[1]];
} else
v1c = v2c = v3c = NULL;
if (v1i[2]>=0 && v2i[2]>=0 && v3i[2]>=0) {
v1n = vnlist[v1i[2]];
v2n = vnlist[v2i[2]];
v3n = vnlist[v3i[2]];
} else
v1n = v2n = v3n = NULL;
return(cvtri(getmod(), vlist[v1i[0]], vlist[v2i[0]], vlist[v3i[0]],
v1n, v2n, v3n, v1c, v2c, v3c) >= 0);
}
int
cvpoly( /* convert a polygon to extended triangles */
OBJECT mo,
int n,
FVECT *vp,
FVECT *vn,
RREAL (*vc)[2]
)
{
int tcnt = 0;
int flags;
RREAL *tn[3], *tc[3];
int *ord;
int i, j;
if (n < 3) /* degenerate face */
return(0);
flags = MT_V;
if (vn != NULL) {
tn[0] = vn[0]; tn[1] = vn[1]; tn[2] = vn[2];
flags |= MT_N;
} else {
tn[0] = tn[1] = tn[2] = NULL;
}
if (vc != NULL) {
tc[0] = vc[0]; tc[1] = vc[1]; tc[2] = vc[2];
flags |= MT_UV;
} else {
tc[0] = tc[1] = tc[2] = NULL;
}
if (n == 3) /* output single triangle */
return(cvtri(mo, vp[0], vp[1], vp[2],
tn[0], tn[1], tn[2],
tc[0], tc[1], tc[2]));
/* decimate polygon (assumes convex) */
ord = (int *)malloc(n*sizeof(int));
if (ord == NULL)
error(SYSTEM, "out of memory in cvpoly");
for (i = n; i--; )
ord[i] = i;
while (n >= 3) {
if (flags & MT_N)
for (i = 3; i--; )
tn[i] = vn[ord[i]];
if (flags & MT_UV)
for (i = 3; i--; )
tc[i] = vc[ord[i]];
tcnt += cvtri(mo, vp[ord[0]], vp[ord[1]], vp[ord[2]],
tn[0], tn[1], tn[2],
tc[0], tc[1], tc[2]);
/* remove vertex and rotate */
n--;
j = ord[0];
for (i = 0; i < n-1; i++)
ord[i] = ord[i+2];
ord[i] = j;
}
free((void *)ord);
return(tcnt);
}
