Texture handles were resolved to pointers when updating a SamplerGroup,
as that point the handle was checked for use-after-free. However, the
texture could be destroyed later while still active in the SamplerGroup,
this would result in using the pointer which now contains garbage.
We now keep the handle and resolve the texture when binding samplers
to the program; which will also perform the use-after-free check.
If a user is using `setFrameScheduledCallback()`, managing the provided PresentCallable during engine shutdown is tricky -- we'll likely get a final frame scheduled when we flush the engine's work queue, but the PresentCallable will schedule the final CAMetalDrawable to be released on main thread afterwards, even if we call `present(false)` to skip it. If the swap chain is destroyed before that main queue block gets executed, the mutex presenting that drawable will no longer exist, causing a crash.
To make things easier, store the std::mutex in a shared_ptr, so that a PresentCallable can safely outlive the FSwapChain instance that created it and clean itself up afterwards.
Alternatives considered, all of which seem unfortunate:
* Require users to clear out the callback before shutting down the engine, so that any final drawables are immediately discarded instead of using PresentCallable
* Require users to split up the engine teardown across two main queue blocks, ensuring that the PresentCallable cleanup executes before swapchains are destroyed
* Drop the PresentCallable on the ground and leak the memory
When a user drags and drops a gltf file to the gltf_viewer window, it
loads the new asset.
While this happens, the function `checkAsset` tries parsing the gltf
file, but it doesn't free it. Fix this.
The number of SH bands used for the indirect light irradiance
computations can be set to 1, 2 or 3 (default) in Material::Builder.
For e.g. in lower-end devices w/ non HDR content, it might be
beneficial to set this value to 2.
BUGS=[341971013]
Abstracts the synchronization of the vulkan swapchain so that it is easier to override during the acquisition and presentation of images. A new structure (ImageSyncData) is created to hold swapchain synchronization data.
FIXES=[338303279]
Ben Doherty
Sungun Park
Tibor Hencz
Mathias Agopian
Ryan
Grant Commodore
Hanno J. Gödecke
Powei Feng
Serge Metral
Romain Guy