Preparing
Before performing a compositing operation on the pre-rendered data some preparation work needs to be done. This is done with the composite_prepare_composite command. The command takes several parameters but the only mandatory one is the composite_name which should match the name used when you rendered the components originally. So, if preparing one of our earlier examples this would be:
{"jsonrpc": "2.0", "method": "compositor_prepare_composite", "params": { "composite_name" : "ex_composite" }, "id": 1}
This will return the existing composite data again for reference but as long as the command does not give an error you can proceed to compositing. You must call this command prior compositing. If you call prepare and the composite is already prepared it will return immediately with the already prepared data.
A prepared composite is ready to perform compositing operations on. You only need to call the prepare command on a composite if it has not already been called since starting RealityServer. If the compositing data is not already in memory it will attempt to load it from disk.