+ oncount++;
+ frac = pdist / (pdist - ndist);
+ if (frontcount < outfrontmaxpoints)
+ {
+ *outfrontpoints++ = p[0] + frac * (n[0] - p[0]);
+ *outfrontpoints++ = p[1] + frac * (n[1] - p[1]);
+ *outfrontpoints++ = p[2] + frac * (n[2] - p[2]);
+ }
+ frontcount++;
+ if (backcount < outbackmaxpoints)
+ {
+ *outbackpoints++ = p[0] + frac * (n[0] - p[0]);
+ *outbackpoints++ = p[1] + frac * (n[1] - p[1]);
+ *outbackpoints++ = p[2] + frac * (n[2] - p[2]);
+ }
+ backcount++;
+ }
+ }
+ }
+ if (neededfrontpoints)
+ *neededfrontpoints = frontcount;
+ if (neededbackpoints)
+ *neededbackpoints = backcount;
+ if (oncountpointer)
+ *oncountpointer = oncount;
+}
+
+void PolygonD_Divide(int innumpoints, const double *inpoints, double planenormalx, double planenormaly, double planenormalz, double planedist, double epsilon, int outfrontmaxpoints, double *outfrontpoints, int *neededfrontpoints, int outbackmaxpoints, double *outbackpoints, int *neededbackpoints, int *oncountpointer)
+{
+ int i = 0, frontcount = 0, backcount = 0, oncount = 0;
+ const double *n, *p;
+ double frac, pdist, ndist;
+ if (innumpoints)
+ {
+ n = inpoints;
+ ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
+ for(i = 0;i < innumpoints;i++)
+ {
+ p = n;
+ pdist = ndist;
+ n = inpoints + ((i + 1) < innumpoints ? (i + 1) : 0) * 3;
+ ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
+ if (pdist >= -epsilon)
+ {
+ if (pdist <= epsilon)
+ oncount++;
+ if (frontcount < outfrontmaxpoints)
+ {
+ *outfrontpoints++ = p[0];
+ *outfrontpoints++ = p[1];
+ *outfrontpoints++ = p[2];
+ }
+ frontcount++;
+ }
+ if (pdist <= epsilon)
+ {
+ if (backcount < outbackmaxpoints)
+ {
+ *outbackpoints++ = p[0];
+ *outbackpoints++ = p[1];
+ *outbackpoints++ = p[2];
+ }
+ backcount++;
+ }
+ if ((pdist > epsilon && ndist < -epsilon) || (pdist < -epsilon && ndist > epsilon))
+ {
+ oncount++;
+ frac = pdist / (pdist - ndist);
+ if (frontcount < outfrontmaxpoints)
+ {
+ *outfrontpoints++ = p[0] + frac * (n[0] - p[0]);
+ *outfrontpoints++ = p[1] + frac * (n[1] - p[1]);
+ *outfrontpoints++ = p[2] + frac * (n[2] - p[2]);
+ }
+ frontcount++;
+ if (backcount < outbackmaxpoints)
+ {
+ *outbackpoints++ = p[0] + frac * (n[0] - p[0]);
+ *outbackpoints++ = p[1] + frac * (n[1] - p[1]);
+ *outbackpoints++ = p[2] + frac * (n[2] - p[2]);
+ }
+ backcount++;