When your application receives a request to move to the background, it must release the foreground.
The request is in the form of the system message
For more information, see
and the ProcUI Library.
After your application has received the message, it must perform the following.
When your application is prepared to move to the background, you must call
OS function on each and all cores. All cores synchronize inside the kernel
on this call to have the foreground switch take place.
While a process transitions to the background (i.e., it is in the "RELEASING" state), it may continue to use GX2 and MEM1 as normal. However, it should complete all drawing activity, display its final frame, and release all MEM1 resources before doing its final transition to the background state. Prior to releasing the foreground, the main graphics core (the one which called GX2Init) must call GX2DrawDone after all rendering is complete. This guarantees that all command buffer data has been dispatched to the GPU and completed. There are two ways to perform this using the ProcUI system:
ProcUIRegisterCallbackthat performs the following.
In addition to guaranteeing that the main core's command buffer has been flushed, all display list generation on the other threads/cores must also stop. Therefore the application must call GX2EndDisplayList in all other rendering threads/cores if a display list is being generated prior to switching to the background. While in the background state, no further GX2 operations should be performed until the main core has reentered the foreground. After the main core switches to the background, other threads/cores may partially overrun their time slice. To avoid overrunning and writing new GX2 commands on these cores, stop all threads that issue GX2 commands prior to calling GX2DrawDone in the above sequence.
After performing a process switch using the
ProcUIProcessMessages function, threads overrun slightly, except the thread that called
ProcUIProcessMessages. To avoid the overrun when calling
ProcUIProcessMessages, stop the thread on which a GX2 command is issued.
For example, if you have an asynchronous thread for loading that also creates a display list, you must use a mutex or other exclusive locking construct to lock the place where the display list is created and the place where
ProcUIProcessMessages is called.
The GX2SetTVEnable and GX2SetDRCEnable functions sets a flag after the last frame is cleared that instructs the system that the application allowed rendering to occur. When a process releases the foreground, GX2 can store the last frame that the application displayed. The flag that these functions set determines whether the frame is stored.
In addition, under the current implementation, at each process switch, this flag is cleared after the last frame is stored. Although the black screen is cleared when the application acquires the foreground, the application must pass
TRUE to these functions every time.
To simplify your implementation:
GX2_TRUEwhen you call GX2SetTVEnable and GX2SetDRCEnable. Never pass
GX2_FALSEwhen you call these functions.
ProcUIDrawDoneReleasefunction with GX2SetTVEnable and GX2SetDRCEnable before switching processes.
When a user presses the HOME Button during gameplay, the game moves to the background. Some games continue to run in the background. For example, an online game might communicate in the background to maintain its connection. Only Core 2 is available in the background. Core 0 and Core 1 are not available.
If the game moves to the background with a thread on Core 0 or Core 1, and the thread leaves a mutex locked:
See Foreground Resources for a list of all foreground-only resources.
OSSetScreenCapturePermission to enable/disable the ability for the
system to save a screen capture.
OSReleaseForeground from all three cores.
To switch which process is in the foreground, two transitions occur:
The more complex transition of the two is switching from the foreground to the background.
A foreground switch is cooperative with both the current and next foreground processes. First, the current foreground process will receive a message from the system message queue to release the foreground. When the process responds to this message it will allow the next foreground process to acquire the foreground. A process does not have the foreground taken away without its knowledge and a background process cannot force itself into the foreground.
To switch which process is in the foreground, the current foreground process must first release the foreground before the next foreground process can move to the foreground.
If not using ProcUI, to begin this process, the current foreground process receives a message from the system
message queue with
If using ProcUI, at every frame, the current foreground process should call
ProcUIProcessMessages. This function
will handle any system messages, call
PROCUI_MESSAGE_RELEASE callbacks as appropriate, and block while in the
RELEASE_FORGROUND message is received, or in the
PROCUI_MESSAGE_RELEASE callbacks, the process must:
OSReleaseForegroundfrom all three cores
When a process releases the foreground, the controller states as used by WPAD and KPAD are saved, and when the foreground is again acquired, WPAD and KPAD try to restore these states. This is helpful because the controller setup may change in the other process, for example, turning on or off DPD or MPLS.
Here are some issues to consider after a process switch:
There are only a few reasons for a process to receive the
What happens when a game is in the middle of a file system (FS) or network (NET) API call during the switch from foreground to background modes? Consider two cases:
2014/01/23 Terminology fix.