物理引擎系统-ode

 // now do something with body and joint lists
    dInternalStepIsland (world,body,bcount,joint,jcount,stepsize);

    // what we've just done may have altered the body/joint tag values.
    // we must make sure that these tags are nonzero.
    // also make sure all bodies are in the enabled state.
    int i;
    for (i=0; i       body[i]->tag = 1;
      body[i]->flags &= ~dxBodyDisabled;
    }
    for (i=0; itag = 1;
  }

  // if debugging, check that all objects (except for disabled bodies,
  // unconnected joints, and joints that are connected to disabled bodies)
  // were tagged.
# ifndef dNODEBUG
  for (b=world->firstbody; b; b=(dxBody*)b->next) {
    if (b->flags & dxBodyDisabled) {
      if (b->tag) dDebug (0,"disabled body tagged");
    }
    else {
      if (!b->tag) dDebug (0,"enabled body not tagged");
    }
  }
  for (j=world->firstjoint; j; j=(dxJoint*)j->next) {
    if ((j->node[0].body && (j->node[0].body->flags & dxBodyDisabled)==0) ||
    (j->node[1].body && (j->node[1].body->flags & dxBodyDisabled)==0)) {
      if (!j->tag) dDebug (0,"attached enabled joint not tagged");
    }
    else {
      if (j->tag) dDebug (0,"unattached or disabled joint tagged");
    }
  }
# endif

  /******************** breakable joint contribution ***********************/