Allow layers to play animations

src/gmenu2x.cpp

@@ -596,6 +596,24 @@ void GMenu2X::main() {
 
 	bool quit = false;
 	while (!quit) {
+		// Check whether any layers are animating and remove dismissed layers
+		// from the stack.
+		bool animating = false;
+		for (auto it = layers.begin(); it != layers.end(); ) {
+			auto layer = *it;
+			switch (layer->getStatus()) {
+				case Layer::Status::DISMISSED:
+					it = layers.erase(it);
+					break;
+				case Layer::Status::ANIMATING:
+					animating = true;
+					// fall through
+				case Layer::Status::PASSIVE:
+					++it;
+					break;
+			}
+		}
+
 		// Paint layers.
 		for (auto layer : layers) {
 			layer->paint(*s);
@@ -613,20 +631,19 @@ void GMenu2X::main() {
 		}
 
 		// Handle other input events.
-		InputManager::Button button = input.waitForPressedButton();
-		for (auto it = layers.rbegin(); it != layers.rend(); ++it) {
-			if ((*it)->handleButtonPress(button)) {
-				break;
-			}
-		}
-
-		// Remove dismissed layers from the stack.
-		for (auto it = layers.begin(); it != layers.end(); ) {
-			auto layer = *it;
-			if (layer->wasDismissed()) {
-				it = layers.erase(it);
-			} else {
-				++it;
+		InputManager::ButtonEvent event;
+		bool gotEvent;
+		const bool wait = !animating;
+		do {
+			do {
+				gotEvent = input.getEvent(&event, wait);
+			} while (gotEvent && event.state != InputManager::PRESSED);
+		} while (wait && !gotEvent);
+		if (gotEvent) {
+			for (auto it = layers.rbegin(); it != layers.rend(); ++it) {
+				if ((*it)->handleButtonPress(event.button)) {
+					break;
+				}
 			}
 		}
 	}

src/helppopup.cpp

@@ -32,14 +32,14 @@ void HelpPopup::paint(Surface &s) {
 
 bool HelpPopup::handleButtonPress(InputManager::Button button) {
 	if (button == InputManager::CANCEL) {
-		dismissed = true;
+		dismiss();
 	}
 	return true;
 }
 
 bool HelpPopup::handleTouchscreen(Touchscreen &ts) {
 	if (ts.pressed()) {
-		dismissed = true;
+		dismiss();
 		ts.setHandled();
 	}
 	return true;

src/inputmanager.h

@@ -58,6 +58,7 @@ public:
 	bool waitForEvent(ButtonEvent *event);
 	Button waitForPressedButton();
 	bool pollEvent(ButtonEvent *event);
+	bool getEvent(ButtonEvent *bevent, bool wait);
 
 private:
 	enum ButtonSource { UNMAPPED, KEYBOARD, JOYSTICK };
@@ -69,7 +70,6 @@ private:
 	Menu *menu;
 
 	void readConfFile(const std::string &conffile);
-	bool getEvent(ButtonEvent *bevent, bool wait);
 
 	ButtonMapEntry buttonMap[BUTTON_TYPE_SIZE];
 #ifndef SDL_JOYSTICK_DISABLED

src/layer.h

@@ -16,6 +16,8 @@ class Touchscreen;
  */
 class Layer {
 public:
+	enum class Status { PASSIVE, ANIMATING, DISMISSED };
+
 	virtual ~Layer() {}
 
 	/**
@@ -36,13 +38,34 @@ public:
 	 */
 	virtual bool handleTouchscreen(Touchscreen &ts) = 0;
 
-	bool wasDismissed() { return dismissed; }
+	Status getStatus() { return status; }
 
 protected:
 	/**
-	 * Set this to true to request the layer to be removed from the stack.
+	 * Request the Layer to be removed from the stack.
+	 * There could be a few more calls to the Layer before it is actually
+	 * removed, so be prepared to handle those.
 	 */
-	bool dismissed = false;
+	void dismiss() {
+		status = Status::DISMISSED;
+	}
+
+	/**
+	 * Request that this layer be repainted every frame.
+	 */
+	void startAnimating() {
+		if (status == Status::PASSIVE) status = Status::ANIMATING;
+	}
+
+	/**
+	 * Request that this layer be repainted only after an event.
+	 */
+	void stopAnimating() {
+		if (status == Status::ANIMATING) status = Status::PASSIVE;
+	}
+
+private:
+	Status status = Status::PASSIVE;
 };
 
 #endif // LAYER_H