All data retrieval, even retrieval from disk, is performed on background threads. It can be pruned programmatically by the application. As remote data is retrieved it is stored in a local disk cache and subsequently used from there. Retrieval and local caching of that data is therefore a necessary and primary feature of WorldWind. WorldWind works with enormous quantities of data and information, all of which exist primarily on remote data servers. Objects implementing a particular interface may be used wherever that interface is called for. The WorldWindow’s scene controller subsequently manages the display of the globe and its layers, in conjunction with an interactive view that defines the user’s view of the planet.Īll the objects above can be those provided by WorldWind or those developed by application developers. They also create a WorldWindow and pass the model to it. In typical usage, applications create a globe and layers for their data and combine them into a model. SceneController controls the rendering of a Model and the timing of the rendering.View determines the user’s view of the model and is driven by input events from the user via the InputHandler.Model aggregates the globe and its layers, including in-screen layers.Layers also provide in-screen shapes that lie in the plane of the screen and do not move with the globe. These items all retain their position relative to the globe as the user navigates through the geography. Layer applies application imagery, shapes or other information to the globe.The globe has a Tessellator that generates the terrain. Globe represents a planet’s shape and terrain.In addition to WorldWindow, there are several major WorldWind interfaces, all shown in the following diagram. Extensibility is a fundamental objective of WorldWind. Concrete classes can also be replaced or extended. The API is defined primarily by interfaces, so components can be selectively replaced by alternative components. That WorldWindow provide the 3D geographic context for the application’s information and behaviors. Applications use WorldWind by placing one or more WorldWindow objects in their user interface. WorldWind is a collection of components that interactively display 3D geographic information within Java applications.
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