Factories

Created by: joansola

Hello. Factories for the following objects are ready and working in branch 'master':

• SensorXxx
• ProcessorXxx
• IntrinsicsXxx
• ProcessorParamsXxx

It is now interesting that you take your objects and make them factory-enabled. Basically, using these factories serves to create these objects easily from information provided either from text, or from configuration files. This is useful in the main() functions of our applications, or in the ROS nodes.

It is therefore convenient that you upgrade your main() and ROS nodes to make use of this functionality.

Please look at test_yaml.cpp, test_wolf_factories.cpp, and test_image.cpp for examples of use. In particular, look at the way to add sensors and processors to Problem:

• Problem::installSensor()
• Problem::installProcessor()

Please read the documentation in sensor_factory.h for a thorough explanation of the use of the factories. In particular, you need to ensure that:

• You create methods SensorXxx::create(...) and ProcessorXxx::create(...) to create sensors and processors from the factory. Look at SensorCamera and ProcessorImage for complete examples.
• Register these methods to the factory. Look at sensor_camera.cpp for an example of a registration instruction.
• You create methods createIntrinsicsXxx(...) and createProcessorParamsXxxx(...) to create parameters for your objects from YAML or XML files. Look at yaml/sensor_camera_yaml.cpp for en example. Look also at yaml/processor_image_yaml.cpp.
• You register these methods into the factories. See .cpp files in the directory yaml/

Created by: joansola

@JaimeTarraso I completed most of the actions for your classes to use the Factory. You should now use it in the ROS node. Please look at test_image.cpp to see what you have to do. You can use the current state of your branch 'image'.

@joanvallve You'll probably have to merge master to you branch before.

@AtDinesh you probably do not need to bother about this by now. If you do, you can ask Nicolas in case of any difficulties -- he is aware of the design of the Factories.

Created by: joanvallve

Have you removed the processor installer from the sensor name and the instrinsics ptr?

Created by: joansola

Yes, because it lies halfway between the all-code API and the all-text API and I thought it was misleading. Do you need it, or can you work with the current API?

There is an example in test_image.cpp that should be clear on how to use it. Also in test_wolf_factories.cpp you have different ways of accessing the installers.

Created by: joansola

By now, the way to bind captures to sensors is by returning a pointer to the base sensor when calling installSensor(), and then casting it to derived type if needed. However, you can obtain this pointer from a sensor name using problem.getSensorPtr("Sensor Name").

Created by: joanvallve

I like the all-text API, however, in ROS it is not aplicable.. right? BTW: merged and working in tests and node ;)

Created by: joansola

The IntrinsicsFactory and the ProcessorParamsFactory can be loaded with any creator method that agrees with this:

IntrinsicsBase * create(std::string type, std::string filename);

Therefore, it can be used with ROS' rosparams probably.

At this time, creators from YAML files (wolf style) are automatically registered to the factory. But this will be removed in the future, and registration will be done according to the application needs (WOLF or ROS or other). In fact, each set of params can be created with a different method: just register each creator as desired.

Created by: joanvallve

I don't know which way will be the best..

I found an error (i think), in Problem::installProcessor, there is the option of not passing the parameters (it is nullptr by default), but then it is used in ProcesorFactory::create. So if you call installProcessor without the parameters, it doesn't compile.

Created by: joansola

The default is for constructors that do not need parameters. If you need parameters, then you cannot give a nullptr.

The create() method in Factory also has default mullptr. It calls the derived constructor. If nullptr is entered, it means the derived constructor does not need params.

I think it works... in test_wolf_factories there are tests for different similar situations :

// Install processors and bind them to sensors -- by sensor name!
problem.installProcessor("ODOM 2D", "main odometry",    "main odometer");
problem.installProcessor("ODOM 3D", "sec. odometry",    "aux odometer");
problem.installProcessor("IMU",     "pre-integrated",   "inertial");
problem.installProcessor("IMAGE", "ORB", "front left camera", "/home/jsola/dev/wolf/src/examples/processor_image_ORB.yaml");

Created by: joanvallve

Sorry.. Yes I know, in ProcessorOdom2D, I used this option. But this morning the compiler complained about line 41 in processor_factory.cpp where this is used. But not now, it compiles. Weird..

Closing. I'll open a new issue on Factories.

Status changed to closed