From 25a2d9b5b5be2b6b7f204a747e3e0b95b3a36a0d Mon Sep 17 00:00:00 2001
From: jacob1 <jfu614@gmail.com>
Date: Sun, 13 Nov 2016 19:22:21 -0500
Subject: [PATCH] some modifications to ctrl+z/ctrl+y

allows infinite undoing / redoing, improvements when history limit is greater than one
---
 src/gui/game/GameController.cpp | 45 +++++++++++++++++----------------
 src/gui/game/GameModel.cpp      | 11 ++++++++
 src/gui/game/GameModel.h        |  3 +++
 3 files changed, 37 insertions(+), 22 deletions(-)

diff --git a/src/gui/game/GameController.cpp b/src/gui/game/GameController.cpp
index f65772fad..10e966d5f 100644
--- a/src/gui/game/GameController.cpp
+++ b/src/gui/game/GameController.cpp
@@ -233,18 +233,18 @@ void GameController::HistoryRestore()
 {
 	std::deque<Snapshot*> history = gameModel->GetHistory();
 	unsigned int historyPosition = gameModel->GetHistoryPosition();
-	if(historyPosition > 0 && historyPosition <= history.size())
+	unsigned int newHistoryPosition = std::max((int)historyPosition-1, 0);
+	// When undoing, save the current state as a final redo
+	// This way ctrl+y will always bring you back to the point right before your last ctrl+z
+	if (historyPosition == history.size())
 	{
-		if (historyPosition == history.size())
-		{
-			Snapshot * newSnap = gameModel->GetSimulation()->CreateSnapshot();
-			history.push_back(newSnap);
-		}
-		Snapshot * snap = history[historyPosition - 1];
-		gameModel->GetSimulation()->Restore(*snap);
-		gameModel->SetHistory(history);
-		gameModel->SetHistoryPosition(historyPosition - 1);
+		Snapshot * newSnap = gameModel->GetSimulation()->CreateSnapshot();
+		gameModel->SetRedoHistory(newSnap);
 	}
+	Snapshot * snap = history[newHistoryPosition];
+	gameModel->GetSimulation()->Restore(*snap);
+	gameModel->SetHistory(history);
+	gameModel->SetHistoryPosition(newHistoryPosition);
 }
 
 void GameController::HistorySnapshot()
@@ -252,7 +252,7 @@ void GameController::HistorySnapshot()
 	std::deque<Snapshot*> history = gameModel->GetHistory();
 	unsigned int historyPosition = gameModel->GetHistoryPosition();
 	Snapshot * newSnap = gameModel->GetSimulation()->CreateSnapshot();
-	if(newSnap)
+	if (newSnap)
 	{
 		while (historyPosition < history.size())
 		{
@@ -260,20 +260,17 @@ void GameController::HistorySnapshot()
 			history.pop_back();
 			delete snap;
 		}
-		if(history.size() >= 1) //History limit is current 1
+		if (history.size() >= 1)
 		{
 			Snapshot * snap = history.front();
 			history.pop_front();
-			//snap->Particles.clear();
 			delete snap;
 			if (historyPosition > history.size())
-			{
 				historyPosition--;
-			}
 		}
 		history.push_back(newSnap);
 		gameModel->SetHistory(history);
-		gameModel->SetHistoryPosition(historyPosition + 1);
+		gameModel->SetHistoryPosition(std::min((size_t)historyPosition+1, history.size()));
 	}
 }
 
@@ -281,12 +278,16 @@ void GameController::HistoryForward()
 {
 	std::deque<Snapshot*> history = gameModel->GetHistory();
 	unsigned int historyPosition = gameModel->GetHistoryPosition();
-	if(historyPosition < history.size() - 1)
-	{
-		Snapshot * snap = history[historyPosition + 1];
-		gameModel->GetSimulation()->Restore(*snap);
-		gameModel->SetHistoryPosition(historyPosition + 1);
-	}
+	unsigned int newHistoryPosition = std::min((size_t)historyPosition+1, history.size());
+	Snapshot *snap;
+	if (newHistoryPosition == history.size())
+		snap = gameModel->GetRedoHistory();
+	else
+		snap = history[newHistoryPosition];
+	if (!snap)
+		return;
+	gameModel->GetSimulation()->Restore(*snap);
+	gameModel->SetHistoryPosition(newHistoryPosition);
 }
 
 GameView * GameController::GetView()
diff --git a/src/gui/game/GameModel.cpp b/src/gui/game/GameModel.cpp
index eeb443dab..c44634a95 100644
--- a/src/gui/game/GameModel.cpp
+++ b/src/gui/game/GameModel.cpp
@@ -28,6 +28,7 @@ GameModel::GameModel():
 	currentFile(NULL),
 	currentUser(0, ""),
 	toolStrength(1.0f),
+	redoHistory(NULL),
 	historyPosition(0),
 	activeColourPreset(0),
 	colourSelector(false),
@@ -440,6 +441,16 @@ void GameModel::SetHistoryPosition(unsigned int newHistoryPosition)
 	historyPosition = newHistoryPosition;
 }
 
+Snapshot * GameModel::GetRedoHistory()
+{
+	return redoHistory;
+}
+
+void GameModel::SetRedoHistory(Snapshot * redo)
+{
+	redoHistory = redo;
+}
+
 void GameModel::SetVote(int direction)
 {
 	if(currentSave)
diff --git a/src/gui/game/GameModel.h b/src/gui/game/GameModel.h
index dd15a8766..ea0f7879d 100644
--- a/src/gui/game/GameModel.h
+++ b/src/gui/game/GameModel.h
@@ -65,6 +65,7 @@ private:
 	User currentUser;
 	float toolStrength;
 	std::deque<Snapshot*> history;
+	Snapshot *redoHistory;
 	unsigned int historyPosition;
 
 	size_t activeColourPreset;
@@ -133,6 +134,8 @@ public:
 	unsigned int GetHistoryPosition();
 	void SetHistory(std::deque<Snapshot*> newHistory);
 	void SetHistoryPosition(unsigned int newHistoryPosition);
+	Snapshot * GetRedoHistory();
+	void SetRedoHistory(Snapshot * redo);
 
 	void UpdateQuickOptions();