Working on tutorial refactoring

src/UiManager.cpp

@@ -5,6 +5,7 @@
 #include <iostream>
 #include <algorithm>
 #include <sstream>
+#include <unordered_set>
 #include "GameConstants.h"
 
 namespace FRG {
@@ -1535,6 +1536,14 @@ namespace FRG {
 		renderer.PopProjectionMatrix();
 	}
 
+	// Buttons under a hidden node (the node itself or any ancestor) must not react to touches.
+	static void collectVisibleInteractives(const std::shared_ptr<UiNode>& node, std::unordered_set<const void*>& out) {
+		if (!node || !node->visible) return;
+		if (node->button) out.insert(node->button.get());
+		if (node->textButton) out.insert(node->textButton.get());
+		for (auto& c : node->children) collectVisibleInteractives(c, out);
+	}
+
 	static std::shared_ptr<UiNode> findNodeByName(const std::shared_ptr<UiNode>& node, const std::string& name) {
 		if (!node) return nullptr;
 		if (!name.empty() && node->name == name) return node;
@@ -1847,11 +1856,13 @@ namespace FRG {
 	void UiManager::onTouchDown(int64_t fingerId, int x, int y) {
 		// Iterate allInteractives in reverse DFS order: later-declared elements have higher priority.
 		// At most one button or textButton is pressed per touch.
+		std::unordered_set<const void*> visibleInteractives;
+		collectVisibleInteractives(root, visibleInteractives);
 		for (auto it = allInteractives.rbegin(); it != allInteractives.rend(); ++it) {
 			if (std::holds_alternative<std::shared_ptr<UiButton>>(*it)) {
 				auto& b = std::get<std::shared_ptr<UiButton>>(*it);
 				//logger() << "onTouchDown found the button: " << b->name << std::endl;
-				if (b->state != ButtonState::Disabled &&
+				if (visibleInteractives.count(b.get()) && b->state != ButtonState::Disabled &&
 					b->getClickZoneRect().containsConsideringBorder((float)x, (float)y, b->border)) {
 					b->state = ButtonState::Pressed;
 					pressedButtons[fingerId] = b;
@@ -1861,7 +1872,7 @@ namespace FRG {
 				}
 			} else {
 				auto& tb = std::get<std::shared_ptr<UiTextButton>>(*it);
-				if (tb->state != ButtonState::Disabled &&
+				if (visibleInteractives.count(tb.get()) && tb->state != ButtonState::Disabled &&
 					tb->getClickZoneRect().containsConsideringBorder((float)x, (float)y, tb->border)) {
 					tb->state = ButtonState::Pressed;
 					pressedTextButtons[fingerId] = tb;
@@ -2197,6 +2208,9 @@ namespace FRG {
 		if (!root) return false;
 		auto node = findNodeByName(root, nodeName);
 		if (!node) return false;
+		// Replay the fade-in when a hidden image is revealed, as if its screen was just shown.
+		if (visible && !node->visible && node->staticImage && node->staticImage->fadeInEnabled)
+			node->staticImage->fadeInElapsedMs = 0.0f;
 		node->visible = visible;
 		return true;
 	}