Fixup destroyTriangleBatch batch type

[kcbanner]

This commit was intended to be part of #12

[hazeycode]

Sorry, I changed this to be typed to get the sample apps to work. Why does this need to be type erased?

[kcbanner]

The create functions return a DebugRendererImpl::BatchImpl instance which is constructed via JPC_DebugRenderer_TriangleBatch_Create. BatchImpl is a reference counted wrapper around the user-code batch pointer.

When the destructor for BatchImpl runs, it calls the destroyTriangleBatch function with the user-code batch pointer as the parameter, not the TriangleBatch (aka the BatchImpl) itself. Essentially it's unwrapping the reference to hand the callback the original user-code pointer (instead of needing a getter for it).

[hazeycode]

Ah, thanks for the explanation