From 1dbdcc206561fb84c0ecb12c1b1f351b2403ec71 Mon Sep 17 00:00:00 2001
From: flan <flan@flande.re>
Date: Sun, 21 Sep 2025 20:49:50 +0200
Subject: [PATCH] Don't treat two different consecutive flashes as repeating

Caused by not comparing the previous frame's flash parameters
during the repeating flash check.

The issue can be reproduced in maps with parallel flash+wait
by using a flashing effect action like the rat form toggle in
Collective Unconscious or rainbow/fairy in Yume 2kki. The effect
action triggers the repeating flash condition, even though the
two flashes have different parameters.

Examples of affected maps:
 - Yume 2kki: MAP0160 (Monochrome Street)
 - Yume 2kki: MAP0703 (Florist)
 - Yume 2kki: MAP3594 (Firefly Lake)
 - Collective Unconscious: MAP1407 (Forest)

Regression introduced in a545830a8debcb9c30bda83efb21796fb364982d.
---
 src/multiplayer/game_multiplayer.cpp | 18 +++++++++---------
 src/multiplayer/game_multiplayer.h   |  3 ++-
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/multiplayer/game_multiplayer.cpp b/src/multiplayer/game_multiplayer.cpp
index ccd8688e9..47d0ed97f 100644
--- a/src/multiplayer/game_multiplayer.cpp
+++ b/src/multiplayer/game_multiplayer.cpp
@@ -112,9 +112,10 @@ static bool MovePlayerToPos(Game_PlayerOther& player, int x, int y) {
 }
 
 void Game_Multiplayer::ResetRepeatingFlash() {
+	repeating_flash_active = false;
 	frame_index = 0;
 	last_flash_frame_index = -1;
-	last_frame_flash.reset();
+	last_flash_frame_flash.fill(0);
 	repeating_flashes.clear();
 }
 
@@ -593,16 +594,16 @@ void Game_Multiplayer::MainPlayerFlashed(int r, int g, int b, int p, int f) {
 	std::array<int, 5> flash_array = std::array<int, 5>{ r, g, b, p, f };
 	if (last_flash_frame_index > -1
 			&& frame_index - last_flash_frame_index <= 1
-			&& (last_frame_flash.get() == nullptr || *last_frame_flash == flash_array)) {
-		if (last_frame_flash.get() == nullptr) {
-			last_frame_flash = std::make_unique<std::array<int, 5>>(flash_array);
+			&& last_flash_frame_flash == flash_array) {
+		if (!repeating_flash_active) {
+			repeating_flash_active = true;
 			connection.SendPacketAsync<RepeatingFlashPacket>(r, g, b, p, f);
 		}
 	} else {
 		connection.SendPacketAsync<FlashPacket>(r, g, b, p, f);
-		last_frame_flash.reset();
 	}
 	last_flash_frame_index = frame_index;
+	last_flash_frame_flash = flash_array;
 }
 
 void Game_Multiplayer::MainPlayerChangedTransparency(int transparency) {
@@ -804,12 +805,11 @@ void Game_Multiplayer::UpdateServerVariables() {
 
 void Game_Multiplayer::Update() {
 	if (session_active) {
-		if (last_flash_frame_index > -1
-				&& last_frame_flash.get() != nullptr
-				&& frame_index > last_flash_frame_index) {
+		if (repeating_flash_active && frame_index > last_flash_frame_index) {
 			connection.SendPacketAsync<RemoveRepeatingFlashPacket>();
+			repeating_flash_active = false;
 			last_flash_frame_index = -1;
-			last_frame_flash.reset();
+			last_flash_frame_flash.fill(0);
 		}
 
 		++frame_index;
diff --git a/src/multiplayer/game_multiplayer.h b/src/multiplayer/game_multiplayer.h
index c3435c3a3..955fbe48b 100644
--- a/src/multiplayer/game_multiplayer.h
+++ b/src/multiplayer/game_multiplayer.h
@@ -108,8 +108,9 @@ class Game_Multiplayer {
 	std::vector<std::string> global_sync_picture_prefixes;
 	std::map<int, bool> sync_picture_cache;
 	std::vector<int> sync_battle_anim_ids;
+	bool repeating_flash_active;
 	int last_flash_frame_index{-1};
-	std::unique_ptr<std::array<int, 5>> last_frame_flash;
+	std::array<int, 5> last_flash_frame_flash;
 	std::map<int, std::array<int, 5>> repeating_flashes;
 
 	std::unordered_set<std::string> hrs_set{