At best, it doesn't do anything other than some queue some viewport
changes via SDL_RendererEventWatch(). At worst, it can race with
the render thread and cause trouble.
This significantly hurts performance on slower GPUs by preventing
the pipelining required when frametimes exceed the video frame
interval.
This reverts commit c26e437f40.
The platforms that would most benefit (embedded V4L2 decoders)
either don't use frame pooling or don't synchronize with
modified DMA-BUFs unless eglCreateImage() is called each time.
We can avoid disabling EGL entirely by forcing Qt to use GLES,
which is not impacted by the black window issue. This lets us
simplify back to EGL everywhere.
The latter will still match on a hybrid system when the iGPU's EGL
implementation is in use. This scenario works properly with EGL
rendering in Qt and SDL, so we want to allow that.
Uniforms are attached to the program object, so they don't need to
be set each time we swap between the YUV shader and the overlay
shader.
Since 0 overlays is by far the most common case and > 1 is highly
unlikely, move the glViewport() call into renderOverlay() to let
us skip it in the common case (and be no worse than today in the
2nd most common case of 1 overlay).
Vulkan H.264/HEVC video decoding isn't supported with Fedora's Mesa binaries due to
patent issues, so only the VAAPI/DRM-PRIME import path was tested locally with ANV.
HDR video is getting tonemapped to my SDR monitor reasonably, so HDR output probably
works with GameScope but I haven't confirmed yet.
See #1117
Previously we opted to just lie to SDL and tell it that the current
GL context is actually GLES 3.0 when it wasn't. This meant that
we avoided our window being recreated for GLES usage on Wayland
and KMSDRM, but that meant our 10-bit color change didn't apply
either. I suspect this hackery is what led EGLRenderer to get
stuck in a state where SDL_CreateRenderer() always failed.
Now SDL will recreate our window once to configure a compatible GL
API for our renderer. If that fails, we'll move on to a different
renderer (which may recreate the window again).
