The next thing that needs to be done is to detect the device’s screen resolution that is associated with the VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR as this resolution is the one that the Swapchain will always need to be set to. Get the Identity Screen Resolution and Camera Parameters Also if your application uses a fixed orientation then it will only need to setup the swapchain once on application startup/resume. If your application fixes its screen orientation using the screenOrientation attribute you do not need to do this. This is done by adding the orientation (to support API level #How to rotate screen in andy emulator mac androidThis prevents Android from destroying and recreating the Android activity and calling the onDestroy() function on the existing window surface when an orientation change occurs. To handle device rotation in your app, change the application’s AndroidManifest.xml to tell Android that your app will handle orientation and screen size changes. #How to rotate screen in andy emulator mac how toIn this post we will describe in detail how to implement pre-rotation and handle device rotation in your Vulkan application. Knowing how to set the surface transform flag is important for every Vulkan application, since applications tend to either support multiple orientations, or support a single orientation where its render surface is in a different orientation to what the device considers its identity orientation For example a landscape-only application on a portrait-identity phone, or a portrait-only application on a landscape-identity tablet. The primary mechanism with which this works is by telling the Android OS that we are handling the surface rotation by specifying in the orientation during swapchain creation through the passed in surface transform flags, which stops the Android Compositor from doing the rotation itself. To ensure surface rotations are handled properly with as little overhead as possible (as seen in the case above) we recommend implementing method 3 - this is known as pre-rotation. Handling orientation properly stops GPU preemption by SurfaceFlinger almost entirely, as well as sees the GPU frequency drop 40% as the boosted frequency used by the Android Compositor is no longer needed. On Pixel 4XL, we have seen on shipping titles that SurfaceFlinger (the higher-priority task that drives the Android Compositor) both regularly preempts the application’s work causing 1-3ms hits to frametimes, as well as puts increased pressure on the GPU’s vertex/texture memory as the Compositor has to read the frame to do its composition work. If your application is CPU bound, this becomes a huge power issue due to the increased GPU usage by the Android Compositor which usually is running at a boosted frequency as well and if your application is GPU bound, then it becomes a potentially large performance issue on top of that as the Android Compositor will preempt your application's GPU work causing your application to drop its frame rate. Even if there is a DPU to take care of this for us, there will still likely be a measurable performance penalty to pay. There currently isn't a way for an application to know whether surface rotation handled outside of the application will be free.
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