WebWorker support for MeshLoader plug-ins

[ksons]

Exploit WebWorker to decode mesh data in handlers. This is in particular important for mesh formats that are expensive to deccode, for instance LZMA encoded OpenCTM resources.

Shoudn't be a big issue as Xflow has the capabilities to asychronously fill the data.

[ksons]

We double-checked. this. One could use the Xflow capbabilities already today (set state of Xflow node to loading and will the data in asychronously). However, a better integration into the resource management would be favourable.

[jonnenauha]

Does this also address that custom loaders don't have to return the results right away but instead call a function when its ready. I guess this implies that it would be added to the loader interface, but wasn't sure.

[ksons]

That is exactly the main chnage. Instead of returning the adapter imeediatly, the plug-in would use a callback. Then the resource is considered as pending during encoding and all elements get informed once the decoded resource is available.

[ksons]

This enhancement is implemented and available in 4.5 (c188de3). Here is a running example using the OpenCTM plugin.

Plug-ins are also now part of the repository.