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rocksplit.c
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rocksplit.c
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/*************************************************************
*
* rocksplit.c - Smoothly split a trimesh into two files
*
* Mark J. Stock, [email protected]
*
*
* rocktools - Tools for creating and manipulating triangular meshes
* Copyright (C) 1999,2004,2006-8,14 Mark J. Stock
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*********************************************************** */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#define SPLIT
#include "structs.h"
node_ptr node_head = NULL;
norm_ptr norm_head = NULL;
text_ptr text_head = NULL;
void find_arc_intersection (int, double, VEC, VEC, VEC, VEC, VEC*, VEC*);
int Usage(char[MAX_FN_LEN],int);
int main(int argc,char **argv) {
int i;
int input_format = 0; // integer flag for input file type
int output_format = 0; // integer flag for output file type
int num_read = 0;
int num_wrote_1 = 0; // number of triangles written to file 1
int num_wrote_2 = 0; // number of triangles written to file 2
int num_tris = 0;
int num_nodes = 0;
//int have_normals = 0;
int tri_is_low; // keep the current tri or not?
int trim_tri; // trim the current tri or not?
int node_is_low[3];
double thresh = 0.; // the cutoff threshhold for whatever axis
double frac = 0.; // more dealing with the cutoff
double x_split = 0.0;
double y_split = 0.0;
double z_split = 0.0;
VEC bmin,bmax,cm;
enum use_dir_type {
pick_longest,
x,
y,
z } use_dir = pick_longest;
int vn1,vn2,vn3;
int use_given_root = FALSE;
char infile[MAX_FN_LEN]; /* name of input file */
char extension[4]; /* filename extension if infile */
//char axis_char1 = 'x';
//char axis_char2 = 'X';
char output_string[4] = "raw"; /* format extension for the output */
char output_root[MAX_FN_LEN-5]; /* filename root for the output */
char output_1[MAX_FN_LEN]; /* filename for the output */
char output_2[MAX_FN_LEN]; /* filename for the output */
char progname[MAX_FN_LEN]; /* name of binary executable */
tri_pointer the_tri,ttri1,ttri2;
node_ptr the_nodes[3],tnode1,tnode2;
VEC tnorm1,tnorm2;
FILE *ifp;
FILE *ofp1;
FILE *ofp2;
/* Parse command-line args */
(void) strcpy(progname,argv[0]);
if (argc < 2) (void) Usage(progname,0);
if (strncmp(argv[1], "-help", 2) == 0)
(void) Usage(progname,0);
(void) strcpy(infile,argv[1]);
for (i=2; i<argc; i++) {
if (strncmp(argv[i], "-x", 2) == 0) {
x_split = atof(argv[++i]);
use_dir = x;
} else if (strncmp(argv[i], "-y", 2) == 0) {
y_split = atof(argv[++i]);
use_dir = x;
} else if (strncmp(argv[i], "-z", 2) == 0) {
z_split = atof(argv[++i]);
use_dir = x;
} else if (strncmp(argv[i], "-l", 2) == 0) {
use_dir = pick_longest;
} else if (strncmp(argv[i], "-o", 2) == 0) {
strncpy(output_string,argv[i]+2,3);
} else if (strncmp(argv[i], "-root", 2) == 0) {
strcpy(output_root,argv[++i]);
use_given_root = TRUE;
} else
(void) Usage(progname,0);
}
// if an output filename root has not been given, determine it
if (!use_given_root) {
strncpy(output_root,infile,strlen(output_root));
output_root[strlen(infile)-4] = '\0';
//printf("output root is (%s)\n",output_root);
}
/* Determine the input file format from the .XXX extension, and read it */
strncpy(extension,infile+strlen(infile)-3,3);
if (strncmp(extension, "raw", 3) == 0)
input_format = 1;
else if (strncmp(extension, "tin", 1) == 0)
input_format = 2;
else if (strncmp(extension, "rad", 1) == 0)
input_format = 3;
else {
fprintf(stderr,"Input filename extension is assumed to be (%s)\n",extension);
fprintf(stderr,"This is either not a supported input file format for rocksplit, or you\n");
fprintf(stderr," need to use a proper extension (last 3 characters in filename).\n");
fprintf(stderr,"Supported input file formats are: .raw, .tin, and .rad\n");
exit(0);
}
/* Determine and set the output format key from the string */
if (strncmp(output_string, "raw", 3) == 0)
output_format = 1;
else if (strncmp(output_string, "tin", 3) == 0)
output_format = 2;
else if (strncmp(output_string, "rad", 3) == 0)
output_format = 3;
else {
fprintf(stderr,"Output filename extension is assumed to be (%s)\n",output_string);
fprintf(stderr,"This is either not a supported output file format for rocksplit, or you\n");
fprintf(stderr," need to use a proper extension (standard 3-character extension for format).\n");
fprintf(stderr,"Supported output file formats are: .raw, .tin, and .rad\n");
exit(0);
}
// determine the longest side ------------------------------------------
if (use_dir == pick_longest) {
// call a routine that scans the file and returns the edge lengths
float tempf;
find_mesh_stats(infile,&bmin,&bmax,FALSE,&cm,&tempf,&num_tris,&num_nodes);
// then, compare them to find the splitting direction and value
if (bmax.x-bmin.x > bmax.y-bmin.y) {
if (bmax.z-bmin.z > bmax.x-bmin.x) {
use_dir = z;
z_split = 0.5*(bmax.z+bmin.z);
} else {
use_dir = x;
x_split = 0.5*(bmax.x+bmin.x);
}
} else {
if (bmax.z-bmin.z > bmax.y-bmin.y) {
use_dir = z;
z_split = 0.5*(bmax.z+bmin.z);
} else {
use_dir = y;
y_split = 0.5*(bmax.y+bmin.y);
}
}
if (num_tris == 0) exit(0);
}
// determine the output file names
if (use_dir == x) {
//axis_char1 = 'l';
//axis_char2 = 'X';
fprintf(stderr,"Splitting at x = %g\n",x_split);
} else if (use_dir == y) {
//axis_char1 = 'l';
//axis_char2 = 'Y';
fprintf(stderr,"Splitting at y = %g\n",y_split);
} else {
//axis_char1 = 'l';
//axis_char2 = 'Z';
fprintf(stderr,"Splitting at z = %g\n",z_split);
}
if (output_format == 1) {
strcpy(extension,"raw");
} else if (output_format == 1) {
strcpy(extension,"tin");
} else {
strcpy(extension,"rad");
}
sprintf(output_1,"%s%c.%s",output_root,'l',extension);
sprintf(output_2,"%s%c.%s",output_root,'r',extension);
//fprintf(stdout,"outfile 1 is (%s)\n",output_1);
//fprintf(stdout,"outfile 2 is (%s)\n",output_2);
//exit(0);
// finally, open the files and begin the splitting -----------------------
ofp1 = fopen(output_1,"w");
if (ofp1==NULL) {
fprintf(stderr,"Could not open output file %s\n",output_1);
exit(0);
}
fprintf(stdout,"Opening file %s for writing.\n",output_1);
fflush(stdout);
ofp2 = fopen(output_2,"w");
if (ofp2==NULL) {
fprintf(stderr,"Could not open output file %s\n",output_2);
exit(0);
}
fprintf(stdout,"Opening file %s for writing.\n",output_2);
fflush(stdout);
//fprintf(ofp1,"file 1\n");
//fprintf(ofp2,"file 2\n");
//fclose(ofp1);
//fclose(ofp2);
//exit(0);
/* Set up memory space for the working triangle, and the three nodes */
the_tri = alloc_new_tri();
for (i=0; i<3; i++) {
the_nodes[i] = (NODE *)malloc(sizeof(NODE));
the_tri->node[i] = the_nodes[i];
}
/* these are for the nodes and triangles in case a triangle needs a corner trimmed */
tnode1 = (NODE *)malloc(sizeof(NODE));
tnode2 = (NODE *)malloc(sizeof(NODE));
ttri1 = alloc_new_tri();
for (i=0; i<3; i++) ttri1->norm[i] = (NORM *)malloc(sizeof(NORM));
ttri2 = alloc_new_tri();
for (i=0; i<3; i++) ttri2->norm[i] = (NORM *)malloc(sizeof(NORM));
tnorm1.x = 0.;
tnorm1.y = 0.;
tnorm1.z = 0.;
tnorm2.x = 0.;
tnorm2.y = 0.;
tnorm2.z = 0.;
// Read the input file ---------------------------------------------------
/* open the file for reading */
ifp = fopen(infile,"r");
if (ifp==NULL) {
fprintf(stderr,"Could not open input file %s\n",infile);
exit(0);
}
fprintf(stderr,"Opening file %s, splitting",infile);
fflush(stderr);
/* as long as there are triangles available, operate */
while (get_tri(ifp,input_format,the_tri) == 1) {
num_read++;
tri_is_low = FALSE;
trim_tri = FALSE;
for (i=0; i<3; i++) node_is_low[i] = TRUE;
if (use_dir == x)
for (i=0; i<3; i++)
if (the_tri->node[i]->loc.x > x_split)
node_is_low[i] = FALSE;
if (use_dir == y)
for (i=0; i<3; i++)
if (the_tri->node[i]->loc.y > y_split)
node_is_low[i] = FALSE;
if (use_dir == z)
for (i=0; i<3; i++)
if (the_tri->node[i]->loc.z > z_split)
node_is_low[i] = FALSE;
if (node_is_low[0] && node_is_low[1] && node_is_low[2]) {
tri_is_low = TRUE;
trim_tri = FALSE;
} else if (!node_is_low[0] && !node_is_low[1] && !node_is_low[2]) {
tri_is_low = FALSE;
trim_tri = FALSE;
} else {
tri_is_low = FALSE;
trim_tri = TRUE;
}
// put the triangle where it belongs
if (trim_tri) {
// parts of the triangle go to each side
// v3 is the index of the odd node
vn3 = -1;
if (node_is_low[0] == node_is_low[1]) vn3 = 2;
if (node_is_low[1] == node_is_low[2]) vn3 = 0;
if (node_is_low[2] == node_is_low[0]) vn3 = 1;
vn2 = mod(vn3+2,3);
vn1 = mod(vn2+2,3);
// what are the two intersection points?
if (use_dir == x) { thresh = x_split; i = 0; }
if (use_dir == y) { thresh = y_split; i = 1; }
if (use_dir == z) { thresh = z_split; i = 2; }
// between node vn1 and vn3
if (the_tri->norm[vn1] && the_tri->norm[vn3]) {
find_arc_intersection(i,thresh,
the_tri->node[vn1]->loc, the_tri->norm[vn1]->norm,
the_tri->node[vn3]->loc, the_tri->norm[vn3]->norm,
&tnode1->loc, &tnorm1);
} else {
if (use_dir == x) {
frac = (thresh - the_tri->node[vn1]->loc.x) /
(the_tri->node[vn3]->loc.x - the_tri->node[vn1]->loc.x);
} else if (use_dir == y) {
frac = (thresh - the_tri->node[vn1]->loc.y) /
(the_tri->node[vn3]->loc.y - the_tri->node[vn1]->loc.y);
} else if (use_dir == z) {
frac = (thresh - the_tri->node[vn1]->loc.z) /
(the_tri->node[vn3]->loc.z - the_tri->node[vn1]->loc.z);
}
tnode1->loc.x = the_tri->node[vn1]->loc.x + frac*
(the_tri->node[vn3]->loc.x - the_tri->node[vn1]->loc.x);
tnode1->loc.y = the_tri->node[vn1]->loc.y + frac*
(the_tri->node[vn3]->loc.y - the_tri->node[vn1]->loc.y);
tnode1->loc.z = the_tri->node[vn1]->loc.z + frac*
(the_tri->node[vn3]->loc.z - the_tri->node[vn1]->loc.z);
//tnorm1.x = the_tri->norm[vn1].x + frac*
// (the_tri->norm[vn3].x - the_tri->norm[vn1].x);
//tnorm1.y = the_tri->norm[vn1].y + frac*
// (the_tri->norm[vn3].y - the_tri->norm[vn1].y);
//tnorm1.z = the_tri->norm[vn1].z + frac*
// (the_tri->norm[vn3].z - the_tri->norm[vn1].z);
}
// between node vn2 and vn3
if (the_tri->norm[vn2] && the_tri->norm[vn3]) {
find_arc_intersection(i,thresh,
the_tri->node[vn2]->loc, the_tri->norm[vn2]->norm,
the_tri->node[vn3]->loc, the_tri->norm[vn3]->norm,
&tnode2->loc, &tnorm2);
} else {
if (use_dir == x) {
frac = (thresh - the_tri->node[vn2]->loc.x) /
(the_tri->node[vn3]->loc.x - the_tri->node[vn2]->loc.x);
} else if (use_dir == y) {
frac = (thresh - the_tri->node[vn2]->loc.y) /
(the_tri->node[vn3]->loc.y - the_tri->node[vn2]->loc.y);
} else if (use_dir == z) {
frac = (thresh - the_tri->node[vn2]->loc.z) /
(the_tri->node[vn3]->loc.z - the_tri->node[vn2]->loc.z);
}
tnode2->loc.x = the_tri->node[vn2]->loc.x + frac*
(the_tri->node[vn3]->loc.x - the_tri->node[vn2]->loc.x);
tnode2->loc.y = the_tri->node[vn2]->loc.y + frac*
(the_tri->node[vn3]->loc.y - the_tri->node[vn2]->loc.y);
tnode2->loc.z = the_tri->node[vn2]->loc.z + frac*
(the_tri->node[vn3]->loc.z - the_tri->node[vn2]->loc.z);
//tnorm2.x = the_tri->norm[vn2].x + frac*
// (the_tri->norm[vn3].x - the_tri->norm[vn2].x);
//tnorm2.y = the_tri->norm[vn2].y + frac*
// (the_tri->norm[vn3].y - the_tri->norm[vn2].y);
//tnorm2.z = the_tri->norm[vn2].z + frac*
// (the_tri->norm[vn3].z - the_tri->norm[vn2].z);
}
if (node_is_low[vn3]) {
// the single triangle tip goes to file 1
ttri1->node[0] = the_tri->node[vn3];
ttri1->node[1] = tnode1;
ttri1->node[2] = tnode2;
if (the_tri->norm[0] && the_tri->norm[1] && the_tri->norm[2]) {
ttri1->norm[0]->norm.x = the_tri->norm[vn3]->norm.x;
ttri1->norm[0]->norm.y = the_tri->norm[vn3]->norm.y;
ttri1->norm[0]->norm.z = the_tri->norm[vn3]->norm.z;
ttri1->norm[1]->norm.x = tnorm1.x;
ttri1->norm[1]->norm.y = tnorm1.y;
ttri1->norm[1]->norm.z = tnorm1.z;
ttri1->norm[2]->norm.x = tnorm2.x;
ttri1->norm[2]->norm.y = tnorm2.y;
ttri1->norm[2]->norm.z = tnorm2.z;
}
write_tri(ofp1,output_format,ttri1);
num_wrote_1++;
// the 4-sided triangle base goes to file 2
ttri1->node[0] = the_tri->node[vn1];
ttri1->node[1] = tnode2;
ttri1->node[2] = tnode1;
ttri2->node[0] = the_tri->node[vn2];
ttri2->node[1] = tnode2;
ttri2->node[2] = the_tri->node[vn1];
if (the_tri->norm[0] && the_tri->norm[1] && the_tri->norm[2]) {
ttri1->norm[0]->norm.x = the_tri->norm[vn1]->norm.x;
ttri1->norm[0]->norm.y = the_tri->norm[vn1]->norm.y;
ttri1->norm[0]->norm.z = the_tri->norm[vn1]->norm.z;
ttri1->norm[1]->norm.x = tnorm2.x;
ttri1->norm[1]->norm.y = tnorm2.y;
ttri1->norm[1]->norm.z = tnorm2.z;
ttri1->norm[2]->norm.x = tnorm1.x;
ttri1->norm[2]->norm.y = tnorm1.y;
ttri1->norm[2]->norm.z = tnorm1.z;
ttri2->norm[0]->norm.x = the_tri->norm[vn2]->norm.x;
ttri2->norm[0]->norm.y = the_tri->norm[vn2]->norm.y;
ttri2->norm[0]->norm.z = the_tri->norm[vn2]->norm.z;
ttri2->norm[1]->norm.x = tnorm2.x;
ttri2->norm[1]->norm.y = tnorm2.y;
ttri2->norm[1]->norm.z = tnorm2.z;
ttri2->norm[2]->norm.x = the_tri->norm[vn1]->norm.x;
ttri2->norm[2]->norm.y = the_tri->norm[vn1]->norm.y;
ttri2->norm[2]->norm.z = the_tri->norm[vn1]->norm.z;
}
write_tri(ofp2,output_format,ttri1);
write_tri(ofp2,output_format,ttri2);
num_wrote_2 += 2;
} else {
// the 4-sided triangle base goes to file 1
ttri1->node[0] = the_tri->node[vn1];
ttri1->node[1] = tnode2;
ttri1->node[2] = tnode1;
ttri2->node[0] = the_tri->node[vn2];
ttri2->node[1] = tnode2;
ttri2->node[2] = the_tri->node[vn1];
if (the_tri->norm[0] && the_tri->norm[1] && the_tri->norm[2]) {
ttri1->norm[0]->norm.x = the_tri->norm[vn1]->norm.x;
ttri1->norm[0]->norm.y = the_tri->norm[vn1]->norm.y;
ttri1->norm[0]->norm.z = the_tri->norm[vn1]->norm.z;
ttri1->norm[1]->norm.x = tnorm2.x;
ttri1->norm[1]->norm.y = tnorm2.y;
ttri1->norm[1]->norm.z = tnorm2.z;
ttri1->norm[2]->norm.x = tnorm1.x;
ttri1->norm[2]->norm.y = tnorm1.y;
ttri1->norm[2]->norm.z = tnorm1.z;
ttri2->norm[0]->norm.x = the_tri->norm[vn2]->norm.x;
ttri2->norm[0]->norm.y = the_tri->norm[vn2]->norm.y;
ttri2->norm[0]->norm.z = the_tri->norm[vn2]->norm.z;
ttri2->norm[1]->norm.x = tnorm2.x;
ttri2->norm[1]->norm.y = tnorm2.y;
ttri2->norm[1]->norm.z = tnorm2.z;
ttri2->norm[2]->norm.x = the_tri->norm[vn1]->norm.x;
ttri2->norm[2]->norm.y = the_tri->norm[vn1]->norm.y;
ttri2->norm[2]->norm.z = the_tri->norm[vn1]->norm.z;
}
write_tri(ofp1,output_format,ttri1);
write_tri(ofp1,output_format,ttri2);
num_wrote_1 += 2;
// the single triangle tip goes to file 2
ttri1->node[0] = the_tri->node[vn3];
ttri1->node[1] = tnode1;
ttri1->node[2] = tnode2;
if (the_tri->norm[0] && the_tri->norm[1] && the_tri->norm[2]) {
ttri1->norm[0]->norm.x = the_tri->norm[vn3]->norm.x;
ttri1->norm[0]->norm.y = the_tri->norm[vn3]->norm.y;
ttri1->norm[0]->norm.z = the_tri->norm[vn3]->norm.z;
ttri1->norm[1]->norm.x = tnorm1.x;
ttri1->norm[1]->norm.y = tnorm1.y;
ttri1->norm[1]->norm.z = tnorm1.z;
ttri1->norm[2]->norm.x = tnorm2.x;
ttri1->norm[2]->norm.y = tnorm2.y;
ttri1->norm[2]->norm.z = tnorm2.z;
}
write_tri(ofp2,output_format,ttri1);
num_wrote_2++;
}
} else if (tri_is_low) {
// write the whole triangle to output_1
write_tri(ofp1,output_format,the_tri);
num_wrote_1++;
} else {
// write the whole triangle to output_2
write_tri(ofp2,output_format,the_tri);
num_wrote_2++;
}
if (num_read/DOTPER == (num_read+DPMO)/DOTPER) fprintf(stderr,".");
}
fprintf(stderr,"\n");
fclose(ifp);
fclose(ofp1);
fclose(ofp2);
fprintf(stderr,"Read %d triangles, wrote %d and %d\n",num_read,num_wrote_1,num_wrote_2);
/* fprintf(stderr,"Done.\n"); */
exit(0);
}
/*
* find_arc_intersection uses spline interpolation and a Newton solver
* to determine the intersection of the ideal, smoothed edge with the
* cutting plane
*/
void find_arc_intersection (int dim, double thresh, VEC x1, VEC n1,
VEC x2, VEC n2, VEC *xp, VEC *np) {
int i,j;
int cnt = 0;
double frac,error, lfrac,lerror, ufrac,uerror;
//VEC planenorm,planeinter;
double dl[3],fp[2][3][3],p1[3],p2[3],a[4];
double xp1[3],xp2[3],norm1[3],norm2[3];
// normalize normals
n1 = norm(n1);
n2 = norm(n2);
// convert "VEC" to array
xp1[0] = x1.x;
xp1[1] = x1.y;
xp1[2] = x1.z;
norm1[0] = n1.x;
norm1[1] = n1.y;
norm1[2] = n1.z;
xp2[0] = x2.x;
xp2[1] = x2.y;
xp2[2] = x2.z;
norm2[0] = n2.x;
norm2[1] = n2.y;
norm2[2] = n2.z;
// set up error vector
//planenorm.x = 0.;
//planenorm.y = 0.;
//planenorm.z = 0.;
//if (dim==0) planenorm.x = 1.;
//if (dim==1) planenorm.y = 1.;
//if (dim==2) planenorm.z = 1.;
//planeinter.x = 0.;
//planeinter.y = 0.;
//planeinter.z = 0.;
//if (dim==0) planeinter.x = thresh;
//if (dim==1) planeinter.y = thresh;
//if (dim==2) planeinter.z = thresh;
//fprintf(stderr,"\nx1 %g %g %g n1 %g %g %g\n",x1.x,x1.y,x1.z,n1.x,n1.y,n1.z);
//fprintf(stderr,"x2 %g %g %g n2 %g %g %g\n",x2.x,x2.y,x2.z,n2.x,n2.y,n2.z);
// compute the tangential operator for each node (P = I - nn^T)
for (i=0; i<3; i++) {
for (j=0; j<3; j++) {
fp[0][i][j] = 0.;
fp[1][i][j] = 0.;
}
fp[0][i][i] = 1.;
fp[1][i][i] = 1.;
for (j=0; j<3; j++) {
fp[0][i][j] -= norm1[i]*norm1[j];
fp[1][i][j] -= norm2[i]*norm2[j];
}
}
// find the vector product of each of these with dl
for (i=0; i<3; i++) {
p1[i] = 0.;
p2[i] = 0.;
}
for (i=0; i<3; i++) dl[i] = xp2[i] - xp1[i];
for (i=0; i<3; i++) {
for (j=0; j<3; j++) {
p1[i] += dl[j]*fp[0][i][j];
p2[i] += dl[j]*fp[1][i][j];
}
}
// calculate the spline for only the splitting plane normal axis
// a[0] = f_0
a[0] = xp1[dim];
// a[1] = f'_0
a[1] = p1[dim];
// a[2] = 3 (f_1 - f_0) / h^2 - (f'_1 + 2 f'_0) / h (h=1 for us)
a[2] = 3. * (xp2[dim] - xp1[dim]) - (p2[dim] + 2. * p1[dim]);
// a[3] = 2 (f_0 - f_1) / h^3 + (f'_1 + f'_0) / h^2
a[3] = 2. * (xp1[dim] - xp2[dim]) + (p1[dim] + p2[dim]);
// first guesses
frac = 0.5;
lfrac = 0.0;
lerror = a[0] + a[1]*lfrac + a[2]*lfrac*lfrac + a[3]*lfrac*lfrac*lfrac - thresh;
//fprintf(stderr,"guess %g has error %g\n",lfrac,lerror);
ufrac = 1.0;
uerror = a[0] + a[1]*ufrac + a[2]*ufrac*ufrac + a[3]*ufrac*ufrac*ufrac - thresh;
//fprintf(stderr,"guess %g has error %g\n",ufrac,uerror);
if (lerror*uerror > 0.) {
fprintf(stderr,"degenerate edge?\n");
frac = (thresh - xp1[dim]) / (xp2[dim] - xp1[dim]);
xp->x = xp1[0] + frac*(xp2[0]-xp1[0]);
xp->y = xp1[1] + frac*(xp2[1]-xp1[1]);
xp->z = xp1[2] + frac*(xp2[2]-xp1[2]);
np->x = norm1[0] + frac*(norm2[0]-norm1[0]);
np->y = norm1[1] + frac*(norm2[1]-norm1[1]);
np->z = norm1[2] + frac*(norm2[2]-norm1[2]);
*np = norm(*np);
return;
}
// loop until the error is tiny
error = 1.;
while (fabs(error) > 1.e-7 && ++cnt < 100) {
// take new guess
frac = lfrac - lerror*(ufrac-lfrac)/(uerror-lerror);
// find error
error = a[0] + a[1]*frac + a[2]*frac*frac + a[3]*frac*frac*frac - thresh;
//fprintf(stderr,"guess %g has error %g (%g %g)\n",frac,error,lerror,uerror);
// replace upper or lower bound
if (error*lerror > 0.) {
// current and lower errors have same sign
lerror = error;
lfrac = frac;
} else {
uerror = error;
ufrac = frac;
}
}
// if we finished poorly, take a lame guess and quit
if (cnt > 100) {
fprintf(stderr,"degenerate edge?\n");
frac = (thresh - xp1[dim]) / (xp2[dim] - xp1[dim]);
xp->x = xp1[0] + frac*(xp2[0]-xp1[0]);
xp->y = xp1[1] + frac*(xp2[1]-xp1[1]);
xp->z = xp1[2] + frac*(xp2[2]-xp1[2]);
np->x = norm1[0] + frac*(norm2[0]-norm1[0]);
np->y = norm1[1] + frac*(norm2[1]-norm1[1]);
np->z = norm1[2] + frac*(norm2[2]-norm1[2]);
*np = norm(*np);
return;
}
// if we finished well, use frac to find the full 3D point
for (i=0; i<3; i++) {
a[0] = xp1[i];
a[1] = p1[i];
a[2] = 3. * (xp2[i] - xp1[i]) - (p2[i] + 2. * p1[i]);
a[3] = 2. * (xp1[i] - xp2[i]) + (p1[i] + p2[i]);
xp1[i] = a[0] + a[1]*frac + a[2]*frac*frac + a[3]*frac*frac*frac;
norm1[i] = norm1[i] + frac*(norm2[i]-norm1[i]);
}
xp->x = xp1[0];
xp->y = xp1[1];
xp->z = xp1[2];
np->x = norm1[0];
np->y = norm1[1];
np->z = norm1[2];
// normalize normal
*np = norm(*np);
//fprintf(stderr,"xp %g %g %g np %g %g %g\n",xp->x,xp->y,xp->z,np->x,np->y,np->z);
//exit(0);
return;
}
/*
* This function writes basic usage information to stderr,
* and then quits. Too bad.
*/
int Usage(char progname[MAX_FN_LEN],int status) {
/* Usage for rocksplit */
static char **cpp, *help_message[] =
{
"where [-options] are one or more of the following: ",
" ",
" -x val split the triangle mesh into components completely existing ",
" above and below the given value for x ",
" ",
" -y val same as for -x, but in y-direction ",
" ",
" -z val same as for -x, but in z-direction ",
" ",
" -l Split along middle of longest side, whether x, y, or z ",
" ",
" -root name use 'name' instead of input file root as root of new files ",
" ",
" -okey specify output format, key= raw, rad, or tin ",
" default = raw; ",
" ",
" -help (in place of infile) returns this help information ",
" ",
"The input file can be of .raw, .tin, or .rad format, and the program requires",
" the input file to use its valid 3-character filename extension.",
" ",
"Options may be abbreviated to an unambiguous length (duh).",
" ",
"Program will write two files, only runtime information goes to stdout.",
" Example:",
" rocksplit test.raw -x 0.0 -oraw",
" will produce two files: testl.raw and testr.raw",
" ",
NULL
};
fprintf(stderr, "usage:\n %s infile [-options]\n\n", progname);
for (cpp = help_message; *cpp; cpp++) fprintf(stderr, "%s\n", *cpp);
fflush(stderr);
exit(status);
return(0);
}