Difference between revisions of "Example db walk tree"

(Adding link for latest db_walk_tree)
(merge in the void* update from asad)
 
Line 1: Line 1:
 
[[category:Code examples]]
 
[[category:Code examples]]
 
<blockquote>
 
'''This example is for current stable release 7.24.X. In latest release (7.26.1) the function prototype for db_walk_tree has changed, the corresponding changes to the code are: [[Db_walk_tree|Latest db_walk_tree()]]'''
 
</blockquote>
 
 
 
This is a simple example program that shows how to walk a geometry database while performing some operation on geometry as it is encountered.  In this particular example, we iterate just over regions and simply count them:
 
This is a simple example program that shows how to walk a geometry database while performing some operation on geometry as it is encountered.  In this particular example, we iterate just over regions and simply count them:
  
 +
<source lang="C">
  
<source lang="c">
 
 
#include "common.h"
 
#include "common.h"
 
#include "raytrace.h"
 
#include "raytrace.h"
  
int incr_region(struct db_tree_state *tsp, struct db_full_path *pathp, const struct rt_comb_internal *combp, genptr_t data)
+
int incr_region(struct db_tree_state *tsp, struct db_full_path *pathp, const struct rt_comb_internal *combp, void *data)
 
{
 
{
 
   int *counter = (int*)data;
 
   int *counter = (int*)data;
Line 20: Line 15:
 
}
 
}
  
int
+
int main(int argc, char *argv[]){
main(int argc, char *argv[])
+
 
{
+
 
   struct db_i *dbip;
 
   struct db_i *dbip;
 
   int counter = 0;
 
   int counter = 0;
Line 42: Line 36:
  
 
   bu_log("Database title is:\n%s\n", dbip->dbi_title);
 
   bu_log("Database title is:\n%s\n", dbip->dbi_title);
  bu_log("Units: %s\n", bu_units_string(dbip->dbi_local2base));
+
//  bu_log("Units: %s\n", bu_units_string(dbip->dbi_local2base));
  
 
   if (db_lookup(dbip, argv[2], 1) == NULL) {
 
   if (db_lookup(dbip, argv[2], 1) == NULL) {
Line 54: Line 48:
  
 
   db_walk_tree(dbip, 1, (const char **)argv+2, 1, &state, incr_region, NULL, NULL, &counter);
 
   db_walk_tree(dbip, 1, (const char **)argv+2, 1, &state, incr_region, NULL, NULL, &counter);
 +
 +
  
 
   bu_log("counter is %d\n", counter);
 
   bu_log("counter is %d\n", counter);
 
 
   return 0;
 
   return 0;
}
 
  
 +
}
 
</source>
 
</source>
  
 
If we compile this program and run it on a sample geometry database, we get the following:
 
If we compile this program and run it on a sample geometry database, we get the following:
  
 +
<source lang="bash">
 +
# you may need to replace /usr/brlcad with the path to where BRL-CAD is installed on your system
 +
$ gcc -o db_walk_tree_example -I/usr/brlcad/include -I/usr/brlcad/include/brlcad db_walk_tree_example.c -L/usr/brlcad/lib -lrt -lbu
  
<source lang="bash">
+
$ ./db_walk_tree_example db/ktank.g tank
$ gcc db_walk_tree_example.c -L/usr/brlcad/lib -lrt -lbu -I/usr/brlcad/include -I/usr/brlcad/include/brlcad
+
$ ./a.out db/ktank.g tank
+
 
Database title is:
 
Database title is:
 
Keith's Tank
 
Keith's Tank
Units: in
+
 
 
...incrementing...
 
...incrementing...
 
<... trimmed output ...>
 
<... trimmed output ...>
 
...incrementing...
 
...incrementing...
counter is 80
+
counter is 83
 
+
 
</source>
 
</source>

Latest revision as of 19:52, 15 August 2016

This is a simple example program that shows how to walk a geometry database while performing some operation on geometry as it is encountered. In this particular example, we iterate just over regions and simply count them:

#include "common.h"
#include "raytrace.h"
 
int incr_region(struct db_tree_state *tsp, struct db_full_path *pathp, const struct rt_comb_internal *combp, void *data)
{
  int *counter = (int*)data;
  bu_log("...incrementing...\n");
  (*counter)++;
  return 0;
}
 
int main(int argc, char *argv[]){
 
  struct db_i *dbip;
  int counter = 0;
  struct db_tree_state state = rt_initial_tree_state;
 
  if (argc < 2) {
    bu_exit(0, "need more, db.g obj\n");
  }
 
  dbip = db_open(argv[1], "r");
  if (dbip == NULL) {
    bu_exit(1, "Unable to open %s\n", argv[1]);
  }
 
  if (db_dirbuild(dbip) < 0) {
    db_close(dbip);
    bu_exit(1, "Unable to load %s\n", argv[1]);
  }
 
  bu_log("Database title is:\n%s\n", dbip->dbi_title);
//  bu_log("Units: %s\n", bu_units_string(dbip->dbi_local2base));
 
  if (db_lookup(dbip, argv[2], 1) == NULL) {
    db_close(dbip);
    bu_exit(1, "Unable to find %s\n", argv[2]);
  }
 
  state.ts_dbip = dbip;
  state.ts_resp = &rt_uniresource;
  rt_init_resource( &rt_uniresource, 0, NULL );
 
  db_walk_tree(dbip, 1, (const char **)argv+2, 1, &state, incr_region, NULL, NULL, &counter);
 
 
 
  bu_log("counter is %d\n", counter);
  return 0;
 
}

If we compile this program and run it on a sample geometry database, we get the following:

# you may need to replace /usr/brlcad with the path to where BRL-CAD is installed on your system
$ gcc -o db_walk_tree_example -I/usr/brlcad/include -I/usr/brlcad/include/brlcad db_walk_tree_example.c -L/usr/brlcad/lib -lrt -lbu
 
$ ./db_walk_tree_example db/ktank.g tank
Database title is:
Keith's Tank
 
...incrementing...
<... trimmed output ...>
...incrementing...
counter is 83