The observed behavior is that any nonzero timeout value would hang until the device was paused and resumed. And a zero timeout value would always return 0 frames written even when audio fragments could be heard. Making a manual timeout system unworkable.
None of the straightforward systems imply that there's a detectable problem before the call to AAudioStream_write(). And the callback set within AAudioStreamBuilder_setErrorCallback() does not get called as we enter the hang state.
I've found that AAudioStream_getTimestamp() will report an error state from another thread. So this change codifies that behavior a bit until a better fix or more root cause can be found.
Add hint SDL_HINT_ANDROID_BLOCK_ON_PAUSE_PAUSEAUDIO not to pause audio when
the app goes to background.
(It requires SDL_ANDROID_BLOCK_ON_PAUSE as "Non blocking")
Make sure the thread is actually paused, and context backep-up, before
SurfaceView is destroyed (eg surfaceDestroyed() actually returns).
Add a timeout when surfaceDestroyed() is called, and check 'backup_done' variable.
It prevents crashes like:
#00 pc 000000000000c0d0 /system/lib64/libutils.so (android::RefBase::incStrong(void const*) const+8)
#01 pc 000000000000c7f4 /vendor/lib64/egl/eglSubDriverAndroid.so (EglAndroidWindowSurface::UpdateBufferList(ANativeWindowBuffer*)+284)
#02 pc 000000000000c390 /vendor/lib64/egl/eglSubDriverAndroid.so (EglAndroidWindowSurface::DequeueBuffer()+240)
#03 pc 000000000000bb10 /vendor/lib64/egl/eglSubDriverAndroid.so (EglAndroidWindowSurface::GetBuffer(EglSubResource*, EglMemoryDesc*)+64)
#04 pc 000000000032732c /vendor/lib64/egl/libGLESv2_adreno.so (EglWindowSurface::UpdateResource(EsxContext*)+116)
#05 pc 0000000000326dd0 /vendor/lib64/egl/libGLESv2_adreno.so (EglWindowSurface::GetResource(EsxContext*, EsxResource**, EsxResource**, int)+56)
#06 pc 00000000002ae484 /vendor/lib64/egl/libGLESv2_adreno.so (EsxContext::AcquireBackBuffer(int)+364)
#07 pc 0000000000249680 /vendor/lib64/egl/libGLESv2_adreno.so (EsxContext::Clear(unsigned int, unsigned int, unsigned int, EsxClearValues*)+1800)
#08 pc 00000000002cb52c /vendor/lib64/egl/libGLESv2_adreno.so (EsxGlApiParamValidate::GlClear(EsxDispatch*, unsigned int)+132)
Message in the log, when going to background:
"call to OpenGL ES API with no current context (logged once per thread)"
Because of SDL_WINDOWEVENT_MINIMIZED is sent from the Java Activity thread.
It calls SDL_RendererEventWatch(), _WindowEvent() and glFinish() without context.
Solution is to move sending of SDL_WINDOWEVENT_MINIMIZED to the SDL thread.
Aaron Barany
Add SDL_HINT_VIDEO_EXTERNAL_CONTEXT hint to notify SDL that the graphics context is external. This disables the automatic context save/restore behavior on Android and avoids using OpenGL by default when SDL_WINDOW_VUKLAN isn't set.
When the application wishes to manage the OpenGL contexts on Android, this avoids cases where SDL unbinds the context and creates new contexts, which can interfere with the application's operation.
When using Vulkan and Metal renderer implementations, this avoids SDL forcing OpenGL to be enabled on certain platforms. While using the SDL_WINDOW_VULKAN flag can be used to achieve the same thing, it also causes Vulkan to be loaded. If the application uses Vulkan directly, this is not necessary, and fails window creation when using Metal due to Vulkan not being present. (assuming MoltenVK isn't installed)
It may happen to have the sequence pause()/resume()/pause(), before polling
any events.
Before, it ends in 'resumed' state because as the check is greedy.
Now, always increase the Pause semaphore, and stop at each pause.
It ends in 'paused' state.
Related to bug 3250: set up a reconfiguration of SurfaceView holder.
Turn the screen off manually before the app starts
(repro rate is not 100%..)
"Pause" transition will add events:
SDL_WINDOWEVENT_ENTER
SDL_WINDOWEVENT_FOCUS_LOST
SDL_WINDOWEVENT_MINIMIZED
SDL_APP_WILL ENTER BACKGROUND
SDL_APP_DID ENTER BACKGROUND
"Resume" transition will add events:
SDL_APP_WILL ENTER FOREGROUND
SDL_APP_DID ENTER FOREGROUND
SDL_WINDOWEVENT_FOCUS_GAINED
SDL_WINDOWEVENT_RESTORED
If Android application doesn't empty the event loop in between, it enters in
"paused" state when SDL_WINDOWEVENT_RESTORED is fetched.
See bug 3250 for pratical case.
Use a semaphore to prevent concurrency issues between Java Activity and Native thread code, when using 'Android_Window'.
(Eg. Java sending Touch events, while native code is destroying the main SDL_Window. )
Manuel Sabogal
If SDL is compiled with the Audio subsystem disabled there are some undefined references to the functions ANDROIDAUDIO_ResumeDevices and ANDROIDAUDIO_PauseDevices in the file src/video/android/SDL_androidevents.c.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
