Several things are accomplished in this commit, including:
- Use OIIO instead of our own functions for pixel format conversions
(cleaner code/less for us to maintain)
- Fold all PixelService functions into the PixelFormat class
(cleaner code)
- Moved OpenGL pixel definitions to OpenGL classes and out of the
global classes.
- Add support for RGB buffers as well as RGBA (optimization)
context
More intuitive code flow and allows the user to undock the viewer (which
forcibly destroys and recreates the context) and the viewer will handle
creation of the new texture in said new context.
OIIO 2.x uses std::unique_ptr while 1.x uses raw pointers. Olive can now handle
both, manually destroying the raw pointers when necessary if running on OIIO
1.x.
The workers run in separate threads meaning if any significant change is made
(e.g. parameters changing, or even closing the program), these workers may still
be mid-render. This is particularly problematic when closing since the nodes a
worker is rendering may be deleted mid-render. Render backends now have a
function that pauses the main thread (but starts a second event loop so the UI
isn't frozen) until the worker threads are all finished. This way, massive
changes can be made safely without race conditions.
Implementation isn't perfect yet, viewer/renderer doesn't update yet when
the preference is changed so a sequence needs to be re-opened for the change to
take effect.
A few commits ago, the render behavior was changed to only render within a
user-specified range of the playhead. This works well, but it would still
render from the start of the range (usually before the playhead) to the end,
meaning it couldn't keep up with the playhead as well as it should. This
commit prioritizes frames close to the playhead and renders outwards to
address this.
Previously we had no disk management whatsoever, so we cleared the cache on
every close just to prevent clogging up tester disk space. Now that we are
implementing disk management, there are better things to do on close regarding
disk cache. However, some users may still wish for the app to delete the cache
on close, so it's provided as an option.
frames
Previously, when the video renderer received a dirty cache signal, it would
proceed to extract all frames from the range and queue them. However, this could
be extremely slow for long ranges since it had to iterate through the entire
range and calculate the individual frames it contained. Now, we use the same
range combining system as audio and automatically calculate the next frame
within the range only when necessary. Essentially the same work, but split up
over time and done only when needed leading to no discernible UI pause when
invalidating cache.
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.
Since EmitCachedFrameReady() makes a copy of the texture, we can economize a lot
by re-using the same copied texture for all the times rather than making a
separate copy for each time.
Various backend improvements are included in this commit, mostly for the
benefit of exporting. These include:
- Moving more non-GL code from OpenGL derivatives into base classes
- An "export mode" that changes the cache behavior of video backends
- Using the Viewer's UUID introduced a few commits ago
- No longer hardcoding the pixel format/render mode in the backend (since
they'll inevitably differ when exporting vs previewing)
- Improved signalling for frames that are completed
This was many changes that were largely fundamentally related. They included:
- More const modifiers to enforce read only node graphs
- Support for fragment and vertex shaders from the nodes
- Support for node code loaded externally (embedded into the binary)
- Fixed issue preventing two textures from being used in a shader
- Removed several unused functions and cleaned up code
- Fixed video media node misreading its matrix input
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.
Previous iteration had params attached to the backend and the params couldn't
change without being destroyed and re-instantiated. This is not necessary in
this iteration so doing so only wastes resources.
Since we're now working with a separate proxy copy of the original node graph,
if the user changes a parameter in one of those nodes (triggering an
InvalidateCache signal), the values in our copied graph need to be updated
with these new values too.
Previous iterations would use mutexes to prevent changing of the graph
mid-render, however several user actions would need to capture these mutexes
causing the main thread to hang until the current render job (frame/range of
samples) was complete. We now copy the nodes necessary as part of the "compile"
process so that the main thread shouldn't need nearly as much blocking while
caching occurs.
Updating values rapidly would cause strange jitters as a
byproduct of the viewer trying to update from the renderer while
it was still working. Rather than the viewer trying to access the
the renderer, we now send textures in the initial update signal
to keep everything synchronized.
Both audio and video renderers were working off the same invalidation signal
(i.e. changing audio would also trigger a re-render of the video). This is
obviously suboptimal and now they are separate.
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.
Once again, conceptually this system should work, however it does not seem to
be the most efficient and it wouldn't surprise me if the multithreading was
eventually upgraded to an even more coherent system one day. However for
"core principles" this should be fairly decent.
The previous iteration was fairly OpenGL-heavy. It's now been separated into
a base class that is OpenGL independent and a derived class that is
OpenGL-based. Over time this should allow for portability away from OpenGL
if necessary.
itsmattkc