background processing

android/app/AndroidManifest.xml

@@ -76,9 +76,8 @@
         android:theme="@style/AppTheme"
         android:hardwareAccelerated="true" >
 
-        <!-- Example of setting SDL hints from AndroidManifest.xml:
-        <meta-data android:name="SDL_ENV.SDL_ANDROID_TRAP_BACK_BUTTON" android:value="0"/>
-         -->
+		<!-- setting sdl hints. uses the string value -->
+		<meta-data android:name="SDL_ENV.SDL_ANDROID_BLOCK_ON_PAUSE" android:value="0"/>
 
         <activity android:name="TomatoActivity"
             android:label="@string/app_name"

src/main.cpp

@@ -106,7 +106,7 @@ int main(int argc, char** argv) {
 
 	std::unique_ptr<Screen> screen = std::make_unique<StartScreen>(args, renderer.get(), theme);
 
-
+	bool is_background = false;
 	bool quit = false;
 	while (!quit) {
 		auto new_time = std::chrono::steady_clock::now();
@@ -131,6 +131,10 @@ int main(int argc, char** argv) {
 			if (event.type == SDL_EVENT_QUIT) {
 				quit = true;
 				break;
+			} else if (event.type == SDL_EVENT_WILL_ENTER_BACKGROUND) {
+				is_background = true;
+			} else if (event.type == SDL_EVENT_DID_ENTER_FOREGROUND) {
+				is_background = false;
 			}
 
 			if (screen->handleEvent(event)) {
@@ -143,6 +147,10 @@ int main(int argc, char** argv) {
 			break;
 		}
 
+		if (is_background) {
+			render = false;
+		}
+
 		// can do both in the same loop
 		if (render) {
 			ImGui_ImplSDLRenderer3_NewFrame();