fixes edge cases in Android Native App rendering

Squashed commit of the following:

commit ba7271f
Author: mgood7123 <[email protected]>
Date:   Sat Jul 3 03:12:45 2021 +1000

    use std::atomic instead of std::mutex

commit 54e3973
Author: mgood7123 <[email protected]>
Date:   Tue Jun 29 07:52:35 2021 +1000

    fixes edge cases in Android Native App rendering

Revert "fix possible rendering edge cases"

This reverts commit 3d76fb8.

fix possible rendering edge cases

Update AndroidMain.cpp

add functions for app status

apply validator suggestions

Update AndroidAppBase.hpp

Update AndroidAppBase.cpp

remove unused variables

Author: mgood7123

NativeApp/include/Android/AndroidAppBase.hpp

@@ -26,8 +26,10 @@
 #pragma once
 
 #include <memory>
+#include <atomic>
 
 #include <android_native_app_glue.h>
+#include "FlagEnum.h"
 #include "AppBase.hpp"
 
 #include "NDKHelper.h"
@@ -52,6 +54,31 @@ class AndroidAppBase : public AppBase
     static int32_t HandleInput(android_app* app, AInputEvent* event);
     static void    HandleCmd(android_app* app, int32_t cmd);
 
+    // Android lifecycle status flags.  Not app-specific
+    enum APP_STATUS_FLAGS
+    {
+        APP_STATUS_FLAG_NONE = 0x00000000,
+
+        // Set between onCreate and onDestroy
+        APP_STATUS_FLAG_RUNNING = 0x00000001,
+
+        // Set between onResume and onPause
+        APP_STATUS_FLAG_ACTIVE = 0x00000002,
+
+        // Set between onWindowFocusChanged(true) and (false)
+        APP_STATUS_FLAG_FOCUSED = 0x00000004,
+
+        // Set when the app's SurfaceHolder points to a
+        // valid, nonzero-sized surface
+        APP_STATUS_FLAG_HAS_REAL_SURFACE = 0x00000008
+    };
+
+    APP_STATUS_FLAGS GetAppStatus();
+    void             AddAppStatusFlag(APP_STATUS_FLAGS Flag);
+    void             RemoveAppStatusFlag(APP_STATUS_FLAGS Flag);
+    bool             ValueHasAppStatusFlag(APP_STATUS_FLAGS Value, APP_STATUS_FLAGS Flag);
+    bool             HasAppStatusFlag(APP_STATUS_FLAGS Flag);
+
 protected:
     virtual void Initialize()
     {
@@ -89,11 +116,14 @@ class AndroidAppBase : public AppBase
     void UpdateFPS(float fFPS);
 
     bool initialized_resources_ = false;
-    bool has_focus_             = false;
+
+    std::atomic<APP_STATUS_FLAGS> app_status_{APP_STATUS_FLAG_NONE};
 
     ASensorManager*    sensor_manager_       = nullptr;
     const ASensor*     accelerometer_sensor_ = nullptr;
     ASensorEventQueue* sensor_event_queue_   = nullptr;
 };
 
+DEFINE_FLAG_ENUM_OPERATORS(AndroidAppBase::APP_STATUS_FLAGS)
+
 } // namespace Diligent

NativeApp/src/Android/AndroidAppBase.cpp

@@ -24,6 +24,7 @@
  */
 
 #include "AndroidAppBase.hpp"
+#include "Errors.hpp"
 #include "Timer.hpp"
 
 #include <android/sensor.h>
@@ -118,22 +119,44 @@ void AndroidAppBase::HandleCmd(struct android_app* app, int32_t cmd)
     AndroidAppBase* eng = (AndroidAppBase*)app->userData;
     switch (cmd)
     {
-        case APP_CMD_SAVE_STATE:
-            break;
-
         case APP_CMD_INIT_WINDOW:
-            // The window is being shown, get it ready.
-            if (app->window != NULL)
+            LOG_INFO_MESSAGE("APP_CMD_INIT_WINDOW");
+            app->window = app->pendingWindow;
+            if (app->window &&
+                ANativeWindow_getWidth(app->window) &&
+                ANativeWindow_getHeight(app->window))
             {
+                LOG_INFO_MESSAGE("INIT DISPLAY - HAS SURFACE");
                 eng->InitDisplay();
                 eng->DrawFrame();
+                eng->AddAppStatusFlag(APP_STATUS_FLAG_HAS_REAL_SURFACE);
+            }
+            else
+            {
+                LOG_INFO_MESSAGE("NO SURFACE");
+                eng->RemoveAppStatusFlag(APP_STATUS_FLAG_HAS_REAL_SURFACE);
             }
             break;
 
-        case APP_CMD_CONFIG_CHANGED:
+        case APP_CMD_TERM_WINDOW:
+            LOG_INFO_MESSAGE("APP_CMD_TERM_WINDOW - LOST SURFACE - TERM DISPLAY");
+            {
+                eng->RemoveAppStatusFlag(APP_STATUS_FLAG_HAS_REAL_SURFACE);
+            }
+            eng->TermDisplay();
+            break;
+
+        // Note that as of NDK r21b (21.1.6352462), APP_CMD_CONTENT_RECT_CHANGED event is never
+        // generated by android_native_app_glue
+        case APP_CMD_CONTENT_RECT_CHANGED:
         {
-            // This callback is not reliable for handling orientation changes. Depending on the
-            // device, it may be called before or after the surface has been actually resized.
+            LOG_INFO_MESSAGE("APP_CMD_CONTENT_RECT_CHANGED");
+
+            int32_t new_window_width =
+                app->contentRect.right - app->contentRect.left;
+            int32_t new_window_height =
+                app->contentRect.bottom - app->contentRect.top;
+            eng->WindowResize(new_window_width, new_window_height);
             break;
         }
 
@@ -144,45 +167,82 @@ void AndroidAppBase::HandleCmd(struct android_app* app, int32_t cmd)
         // does not work either - the callback is only called once after the window has been created.
         case APP_CMD_WINDOW_RESIZED:
         {
-            auto new_window_width  = ANativeWindow_getWidth(app->window);
-            auto new_window_height = ANativeWindow_getHeight(app->window);
-            eng->WindowResize(new_window_width, new_window_height);
+            LOG_INFO_MESSAGE("APP_CMD_WINDOW_RESIZED");
+            if (app->window)
+            {
+                int32_t new_window_width  = ANativeWindow_getWidth(app->window);
+                int32_t new_window_height = ANativeWindow_getHeight(app->window);
+                if (new_window_width && new_window_height)
+                {
+                    eng->WindowResize(new_window_width, new_window_height);
+                }
+            }
             break;
         }
 
-        // Note that as of NDK r21b (21.1.6352462), APP_CMD_CONTENT_RECT_CHANGED event is never
-        // generated by android_native_app_glue
-        case APP_CMD_CONTENT_RECT_CHANGED:
-        {
-            auto new_window_width  = app->contentRect.right - app->contentRect.left;
-            auto new_window_height = app->contentRect.bottom - app->contentRect.top;
-            eng->WindowResize(new_window_width, new_window_height);
+        case APP_CMD_GAINED_FOCUS:
+            LOG_INFO_MESSAGE("APP_CMD_GAINED_FOCUS - HAS FOCUS");
+            {
+                eng->AddAppStatusFlag(APP_STATUS_FLAG_FOCUSED);
+            }
+            eng->ResumeSensors();
+            break;
+
+        case APP_CMD_LOST_FOCUS:
+            LOG_INFO_MESSAGE("APP_CMD_LOST_FOCUS - LOST FOCUS");
+            {
+                eng->RemoveAppStatusFlag(APP_STATUS_FLAG_FOCUSED);
+            }
+            eng->SuspendSensors();
+            break;
+
+        case APP_CMD_RESUME:
+            LOG_INFO_MESSAGE("APP_CMD_RESUME - IS ACTIVE");
+            {
+                eng->AddAppStatusFlag(APP_STATUS_FLAG_ACTIVE);
+            }
+            break;
+
+        case APP_CMD_START:
+            LOG_INFO_MESSAGE("APP_CMD_START");
             break;
-        }
 
-        case APP_CMD_TERM_WINDOW:
         case APP_CMD_PAUSE:
-            // The window is being hidden or closed, clean it up.
-            eng->TermDisplay();
-            eng->has_focus_ = false;
+            LOG_INFO_MESSAGE("APP_CMD_PAUSE - IS NOT ACTIVE");
+            {
+                eng->RemoveAppStatusFlag(APP_STATUS_FLAG_ACTIVE);
+            }
             break;
 
         case APP_CMD_STOP:
+            LOG_INFO_MESSAGE("APP_CMD_STOP");
             break;
 
-        case APP_CMD_GAINED_FOCUS:
-            eng->ResumeSensors();
-            //Start animation
-            eng->has_focus_ = true;
+        case APP_CMD_CONFIG_CHANGED:
+            LOG_INFO_MESSAGE("APP_CMD_CONFIG_CHANGED");
+            // AConfiguration_fromAssetManager(app->config, app->activity->assetManager);
+            // This callback is not reliable for handling orientation changes. Depending on the
+            // device, it may be called before or after the surface has been actually resized.
             break;
 
-        case APP_CMD_LOST_FOCUS:
-            eng->SuspendSensors();
-            // Also stop animating.
-            eng->has_focus_ = false;
+        case APP_CMD_DESTROY:
+            LOG_INFO_MESSAGE("APP_CMD_DESTROY - IS NOT RUNNING");
+            {
+                eng->RemoveAppStatusFlag(APP_STATUS_FLAG_RUNNING);
+            }
+            break;
+
+        case APP_CMD_WINDOW_REDRAW_NEEDED:
+            LOG_INFO_MESSAGE("APP_CMD_WINDOW_REDRAW_NEEDED");
+            if (eng->IsReady()) eng->DrawFrame();
+            break;
+
+        case APP_CMD_SAVE_STATE:
+            LOG_INFO_MESSAGE("APP_CMD_SAVE_STATE");
             break;
 
         case APP_CMD_LOW_MEMORY:
+            LOG_INFO_MESSAGE("APP_CMD_LOW_MEMORY");
             //Free up GL resources
             eng->TrimMemory();
             break;
@@ -244,10 +304,11 @@ void AndroidAppBase::SetState(android_app* state, const char* native_activity_cl
 
 bool AndroidAppBase::IsReady()
 {
-    if (has_focus_)
-        return true;
-
-    return false;
+    APP_STATUS_FLAGS app_status = GetAppStatus();
+    return ValueHasAppStatusFlag(app_status, APP_STATUS_FLAG_RUNNING) &&
+        ValueHasAppStatusFlag(app_status, APP_STATUS_FLAG_ACTIVE) &&
+        ValueHasAppStatusFlag(app_status, APP_STATUS_FLAG_FOCUSED) &&
+        ValueHasAppStatusFlag(app_status, APP_STATUS_FLAG_HAS_REAL_SURFACE);
 }
 
 //void Engine::TransformPosition( ndk_helper::Vec2& vec )
@@ -285,4 +346,37 @@ void AndroidAppBase::UpdateFPS(float fFPS)
     return;
 }
 
+AndroidAppBase::APP_STATUS_FLAGS AndroidAppBase::GetAppStatus()
+{
+    return app_status_.load();
+}
+
+void AndroidAppBase::AddAppStatusFlag(AndroidAppBase::APP_STATUS_FLAGS Flag)
+{
+    auto LastStoredValue = app_status_.load();
+    while (!app_status_.compare_exchange_weak(LastStoredValue, static_cast<APP_STATUS_FLAGS>(LastStoredValue | Flag)))
+    {
+        // If exchange fails, LastStoredValue will hold the actual value of app_status_.
+    }
+}
+
+void AndroidAppBase::RemoveAppStatusFlag(AndroidAppBase::APP_STATUS_FLAGS Flag)
+{
+    auto LastStoredValue = app_status_.load();
+    while (!app_status_.compare_exchange_weak(LastStoredValue, static_cast<APP_STATUS_FLAGS>(LastStoredValue & ~Flag)))
+    {
+        // If exchange fails, LastStoredValue will hold the actual value of app_status_.
+    }
+}
+
+bool AndroidAppBase::ValueHasAppStatusFlag(AndroidAppBase::APP_STATUS_FLAGS Value, AndroidAppBase::APP_STATUS_FLAGS Flag)
+{
+    return (Value & Flag) != APP_STATUS_FLAG_NONE;
+}
+
+bool AndroidAppBase::HasAppStatusFlag(AndroidAppBase::APP_STATUS_FLAGS Flag)
+{
+    return ValueHasAppStatusFlag(app_status_.load(), Flag);
+}
+
 } // namespace Diligent

NativeApp/src/Android/AndroidMain.cpp

@@ -42,6 +42,9 @@ using namespace Diligent;
 void android_main(android_app* state)
 {
     std::unique_ptr<AndroidAppBase> theApp(CreateApplication());
+
+    theApp->AddAppStatusFlag(AndroidAppBase::APP_STATUS_FLAG_RUNNING);
+
     theApp->SetState(state, NATIVEACTIVITY_CLASS_NAME);
 
     //Init helper functions