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Howto:Extending Canvas to support rendering 3D models: Difference between revisions
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Howto:Extending Canvas to support rendering 3D models (view source)
Revision as of 19:36, 7 March 2015
, 7 March 2015→Turning the filename into a property
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== Turning the filename into a property == | == Turning the filename into a property == | ||
So far, we really only have a proof-of-concept loading a hard-coded 3D model from disk and adding this to a Canvas scene-graph. | |||
However, to be really useful, the file name should not be hard-coded, but should be just a property living in the sub-tree of the corresponding Canvas element, which is what we're going to implement next. Again, it makes sense to look at existing/similar use-cases in FlightGear, and specifically the corresponding subsystem, i.e. Canvas in this case - for that, we can simply look at the implementation of CanvasImage, which already supports the notion of a "filename", which will update the whole element once modified: | |||
https://gitorious.org/fg/simgear/source/ca7acb1f2cb10e4a8db2434642f44f2eb23cce6e:simgear/canvas/elements/CanvasImage.cxx#L613 | |||
<syntaxhighlight lang="cpp"> | |||
if( name == "file" ) | |||
SG_LOG(SG_GL, SG_WARN, "'file' is deprecated. Use 'src' instead"); | |||
</syntaxhighlight> | |||
As can be seen here, the general idea is to use the <code>::childChanged(SGPropertyNode* child)</code> method to look for supported nodes and process updates accordingly. The main thing to keep in mind here is that Canvas/SimGear don't know anything about FlightGear-specific APIs, which is why the CanvasSystemAdapter needs to be used, and called, to expose/access the corresponding APIs: | |||
https://gitorious.org/fg/simgear/source/ca7acb1f2cb10e4a8db2434642f44f2eb23cce6e:simgear/canvas/elements/CanvasImage.cxx#L680 | |||
<syntaxhighlight lang="cpp"> | |||
Canvas::getSystemAdapter() | |||
->getHTTPClient() | |||
->load(url) | |||
// TODO handle capture of 'this' | |||
->done(this, &Image::handleImageLoadDone); | |||
</syntaxhighlight> | |||
== Using ProxyNode == | == Using ProxyNode == | ||
== Adding a PositionAttitudeTransform == | == Adding a PositionAttitudeTransform == | ||