than overwritten on some platforms
Despite the fact we don't actually do any reading here, using
QFile::WriteOnly on its own will truncate the file to 0 bytes which is
undesirable. The documentation says QFile::ReadOnly, Append or NewOnly
will prevent this. NewOnly won't work and reads are unnecessary, so
Append was used initially. However on some platforms, Append will _only_
allow writing at the end of the file (ignoring the seek() function)
meaning bytes won't be written where they're meant to be (this behavior
happens on Linux and not on Windows, the platform discrepancy is likely
a Qt bug). Using ReadWrite instead, despite not reading anything,
prevents truncation and allows for writing not at the end of the file.
The renderer backend can now distinguish between jobs. Previously if two jobs
of the same frame were started (which is legal if the user made a change while
frames were still being rendered), an earlier job in some situations could
finish AFTER a later job, and the backend would have no way of distinguishing
between them. This meant a frame could be erroneously set to an old value
rather than the newest. This commit introduces job identification so that old
jobs are automatically discarded.
Workers run in different threads and the backends can poll whether the worker
is currently busy or not. However the previous iteration has the worker (and an
atomic int) provide the busy state which could easily desync with the main
thread (since all workers run in different threads). By holding the busy states
in the main thread, the main thread will always be able to poll the busy state
accurately.
If the nodes are now stateless, there's nothing stopping the renderer from
rendering multiple frames at once. Earlier since the nodes held some of their
input/output data (and that data could change per frame), it was not possible
to render multiple frames at once without conflicts. Now that the node state is
held in render threads, they can do whatever they want at any time.
Largely conforming renderers to new NodeValue system. Code seems a lot cleaner
this way which is a nice advantage. Likely non-functional as this won't
compile just yet and still needs probably another day or two of testing to get
it back to where it was before.
If the bytes retrieved is less than the bytes we expected for the time period
we're rendering, we fill the remainder with silence. Fixes segfault trying to
copy bytes that aren't actually allocated.
Major refactoring work to try sharing as much code as possible between the
video renderers and audio renderers, as well as make them as
platform-independent as possible.
itsmattkc