Difference between revisions of "NaviTrack Tutorial:Integrating:Callback Module"
Line 8: | Line 8: | ||
This module offers callback mechanism to process recieved data on its arrival. | This module offers callback mechanism to process recieved data on its arrival. | ||
All we need to do is to define a callback function to process recieved data, and register it to CallbackModule. | All we need to do is to define a callback function to process recieved data, and register it to CallbackModule. | ||
+ | |||
Once a callback function has been registered, it is invoked every after events arrive at a corresponding node | Once a callback function has been registered, it is invoked every after events arrive at a corresponding node | ||
in NaviTrack data flow, which is defined in a configulation XML file. | in NaviTrack data flow, which is defined in a configulation XML file. | ||
+ | |||
+ | |||
+ | =Sending coordinate data= | ||
+ | See lxxxxx. | ||
+ | |||
+ | |||
+ | =Receiving coordinate data= | ||
+ | To receive and process the coordinate data, create a callback function and register it to CallbackModule. | ||
+ | |||
+ | ===Register callback function and start context of NaviTrack=== | ||
+ | In main() of pullpos_cbm.cxx. | ||
+ | |||
+ | CallbackModule* cbm = (CallbackModule*) context.getModule("CallbackConfig"); | ||
+ | if (cbm == NULL) { | ||
+ | cerr << "Failed to load CallbackConfig Module." << endl; | ||
+ | } | ||
+ | |||
+ | cbm->setCallback( "cb1", (OTCallbackFunction*)&callbackFunc , NULL); | ||
+ | context.runAtRate(1000.0/(double)interval); | ||
+ | |||
+ | ===Define callback function itself=== | ||
+ | |||
+ | void callbackFunc(Node&, Event &event, void *) | ||
+ | { | ||
+ | vector<float> position(3, 0.0); | ||
+ | vector<float> orientation(4, 0.0); | ||
+ | |||
+ | if (event.hasAttribute("position")) { | ||
+ | for(int i = 0; i < 3; i ++) | ||
+ | position[i]=event.getPosition()[i]; | ||
+ | } else { | ||
+ | position[0]=0.0; | ||
+ | position[1]=0.0; | ||
+ | position[2]=0.0; | ||
+ | } | ||
+ | |||
+ | if (event.hasAttribute("orientation")) { | ||
+ | for (int i = 0; i < 4; i ++) { | ||
+ | orientation[i]= event.getOrientation()[i]; | ||
+ | } | ||
+ | } else { | ||
+ | orientation[0]=0.0; | ||
+ | orientation[1]=0.0; | ||
+ | orientation[2]=0.0; | ||
+ | orientation[3]=0.0; | ||
+ | } | ||
+ | |||
+ | cout << "Received position = (" | ||
+ | << position[0] << ", " << position[1] << ", " << position[2] << "), "; | ||
+ | cout << "orientation = (" | ||
+ | << orientation[0] << ", " << orientation[1] << ", " << orientation[2] << ", " | ||
+ | << orientation[3] << ")" << endl; | ||
+ | |||
+ | } | ||
+ | |||
+ | |||
+ | ===Configure XML file=== | ||
+ | |||
+ | <OpenTracker> | ||
+ | |||
+ | <configuration> | ||
+ | <CallbackConfig/> | ||
+ | <NetworkSinkConfig name="Network"/> | ||
+ | </configuration> | ||
+ | |||
+ | <Callback name="cb1"> | ||
+ | <NetworkSource mode="unicast" number="1" address="b2_d4_7" port="12345"/> | ||
+ | </Callback> | ||
+ | |||
+ | </OpenTracker> | ||
+ | |||
+ | |||
+ | Go back to [[NaviTrack_Tutorial:Integrating_into_your_application]]. |
Revision as of 21:22, 14 June 2007
Home < NaviTrack Tutorial:Integrating:Callback ModuleContents
Overview of CallbackModule
In the previous pages, we have implemented data transfer using NaviTrack into our own programs. The problem here is that they need to poll MyTutorialModule frequently to check if new data have arrived. This couldn't be a serious problem in case of seding small piece of data such as coordinate values, but might cause a waste of CPU time when the data is large.
We can do the almost same thing by using CallbackModule instead of polling. This module offers callback mechanism to process recieved data on its arrival. All we need to do is to define a callback function to process recieved data, and register it to CallbackModule.
Once a callback function has been registered, it is invoked every after events arrive at a corresponding node in NaviTrack data flow, which is defined in a configulation XML file.
Sending coordinate data
See lxxxxx.
Receiving coordinate data
To receive and process the coordinate data, create a callback function and register it to CallbackModule.
In main() of pullpos_cbm.cxx.
CallbackModule* cbm = (CallbackModule*) context.getModule("CallbackConfig"); if (cbm == NULL) { cerr << "Failed to load CallbackConfig Module." << endl; } cbm->setCallback( "cb1", (OTCallbackFunction*)&callbackFunc , NULL); context.runAtRate(1000.0/(double)interval);
Define callback function itself
void callbackFunc(Node&, Event &event, void *) { vector<float> position(3, 0.0); vector<float> orientation(4, 0.0); if (event.hasAttribute("position")) { for(int i = 0; i < 3; i ++) position[i]=event.getPosition()[i]; } else { position[0]=0.0; position[1]=0.0; position[2]=0.0; } if (event.hasAttribute("orientation")) { for (int i = 0; i < 4; i ++) { orientation[i]= event.getOrientation()[i]; } } else { orientation[0]=0.0; orientation[1]=0.0; orientation[2]=0.0; orientation[3]=0.0; } cout << "Received position = (" << position[0] << ", " << position[1] << ", " << position[2] << "), "; cout << "orientation = (" << orientation[0] << ", " << orientation[1] << ", " << orientation[2] << ", " << orientation[3] << ")" << endl; }
Configure XML file
<OpenTracker> <configuration> <CallbackConfig/> <NetworkSinkConfig name="Network"/> </configuration> <Callback name="cb1"> <NetworkSource mode="unicast" number="1" address="b2_d4_7" port="12345"/> </Callback> </OpenTracker>
Go back to NaviTrack_Tutorial:Integrating_into_your_application.