ANDROID_swap_rectangle allows to specify the rectangle affected by eglSwapBuffers(), anything outside of this rectangle is unchanged. in particular EGL_BUFFER_DESTROYED only applies to that rectangle. This extension as well as EGL_BUFFER_PRESERVED allow major optimizations on surfaceflinger, which can redraw only the dirty area during compositing.
However, ANDROID_swap_rectangle allows further optimizations in EGL by reducing the amount of copy-back needed. ANDROID_swap_rectangle is particularily important for software implementations.
- Currently the lock/unlock path is naive and is done for each drawing operation (glDrawElements and glDrawArrays). this should be improved eventually.
- factor all the lock/unlock code in SurfaceBuffer.
- fixed "showupdate" so it works even when we don't have preserving eglSwapBuffers().
- improved the situation with the dirty-region and fixed a problem that caused GL apps to not update.
- make use of LightRefBase() where needed, instead of duplicating its implementation
- add LightRefBase::getStrongCount()
- renamed EGLNativeWindowSurface.cpp to FramebufferNativeWindow.cpp
- disabled copybits test, since it clashes with the new gralloc api
- Camera/Video will be fixed later when we rework the overlay apis
First, the window manager tells us when a surface is no longer needed. At this point, several things happen:
- the surface is removed from the active/visible list
- it is added to a purgatory list, where it waits for all clients to release their reference
- it destroys all data/state that can be spared
Later, when all clients are done, the remains of the Surface are disposed off: it is removed from the purgatory and destroyed.
In particular its gralloc buffers are destroyed at that point (when we're sure nobody is using them anymore).
Surfaces are now destroyed once all references from the clients are gone, but they go through a partial destruction as soon as the window manager requests it.
This last part is still buggy. see comments in SurfaceFlinger::destroySurface()
The WindowManager side of Surface.java holds a SurfaceControl, while the client-side holds a Surface. When the client is in the system process, Surface.java holds both (which is a problem we'll try to fix later).
