982
edits
User:Callahanp: Difference between revisions
Jump to navigation
Jump to search
small edit removing incomplete sentance
(small edit removing incomplete sentance) |
|||
| Line 99: | Line 99: | ||
In FlightGear's C++ code, there are, of course, classes and objects that represent some dataflows. There's a problem, though. Many of the classes are about processing data into ad-hoc structures within the property tree. How can we define a data flow for these ad-hoc structures? (Note: need a way to describe two dataflows. The one that creates the infrastructure as properties in the tree, and a second one implied by the existence of the property.) | In FlightGear's C++ code, there are, of course, classes and objects that represent some dataflows. There's a problem, though. Many of the classes are about processing data into ad-hoc structures within the property tree. How can we define a data flow for these ad-hoc structures? (Note: need a way to describe two dataflows. The one that creates the infrastructure as properties in the tree, and a second one implied by the existence of the property.) | ||
There is no C++ class for an Altimeter or a Heading Indicator. Instead, these are represented by a set of properties and data loaded via XML and other formats. The numerical data, stored in the property tree has a path indicating that the properties underneath a node are for the altimeter or the heading indicator. The actual paths in this case are /instrumentation/altimeter and /instrumentation/heading-indicator. Each node in the tree can have properties as child nodes, as well as child nodes that contain additional properties, such as /instrumentation/heading-indicator/gyro. | There is no C++ class for an Altimeter or a Heading Indicator. Instead, these are represented by a set of properties and data loaded via XML and other formats. The numerical data, stored in the property tree has a path indicating that the properties underneath a node are for the altimeter or the heading indicator. The actual paths in this case are /instrumentation/altimeter and /instrumentation/heading-indicator. Each node in the tree can have properties as child nodes, as well as child nodes that contain additional properties, such as /instrumentation/heading-indicator/gyro. | ||
Properties are created on the fly, once the property tree's root node is instantiated. Properties are specified in XML data, created by a Nasal script, or by C++ code. The actual property mechanism is implemented in a C++ class. | Properties are created on the fly, once the property tree's root node is instantiated. Properties are specified in XML data, created by a Nasal script, or by C++ code. The actual property mechanism is implemented in a C++ class. | ||