AGI: Fix priority band handling

- Fix saving/loading priority bands table. Now saving the actual raw
  data
- Now also saving the flag, that defines if the priority table got
  modified by scripts
- For older saved games it will try to figure out the state of that
  flag
- Blocking set.pri.base for AGI below 2.936
- set.pri.base was actually introduced in 2.936 and not AGI3
- The set.pri.base bug was present in 2.936 as well
- Saved games created between the graphics rewrite and this
  commit may have priority issues for games, that used AGI2.936+

5 files changed, 83 insertions, 25 deletions

diff --git a/engines/agi/graphics.cpp b/engines/agi/graphics.cpp
index b0165154c8..abe3dc707e 100644
--- a/engines/agi/graphics.cpp
+++ b/engines/agi/graphics.cpp
@@ -750,10 +750,15 @@ void GfxMgr::updateScreen() {
 }
 
 void GfxMgr::initPriorityTable() {
+	_priorityTableSet = false;
+
+	createDefaultPriorityTable(_priorityTable);
+}
+
+void GfxMgr::createDefaultPriorityTable(uint8 *priorityTable) {
 	int16 priority, step;
 	int16 yPos = 0;
 
-	_priorityTableSet = false;
 	for (priority = 1; priority < 15; priority++) {
 		for (step = 0; step < 12; step++) {
 			_priorityTable[yPos++] = priority < 4 ? 4 : priority;
@@ -775,11 +780,35 @@ void GfxMgr::setPriorityTable(int16 priorityBase) {
 	}
 }
 
+// used for saving
+int16 GfxMgr::saveLoadGetPriority(int16 yPos) {
+	assert(yPos < SCRIPT_HEIGHT);
+	return _priorityTable[yPos];
+}
+bool GfxMgr::saveLoadWasPriorityTableModified() {
+	return _priorityTableSet;
+}
+
 // used for restoring
-void GfxMgr::setPriority(int16 yPos, int16 priority) {
+void GfxMgr::saveLoadSetPriority(int16 yPos, int16 priority) {
 	assert(yPos < SCRIPT_HEIGHT);
 	_priorityTable[yPos] = priority;
 }
+void GfxMgr::saveLoadSetPriorityTableModifiedBool(bool wasModified) {
+	_priorityTableSet = wasModified;
+}
+void GfxMgr::saveLoadFigureOutPriorityTableModifiedBool() {
+	uint8 defaultPriorityTable[SCRIPT_HEIGHT]; /**< priority table */
+
+	createDefaultPriorityTable(defaultPriorityTable);
+
+	if (memcmp(defaultPriorityTable, _priorityTable, sizeof(_priorityTable)) == 0) {
+		// Match, it is the default table, so reset the flag
+		_priorityTableSet = false;
+	} else {
+		_priorityTableSet = true;
+	}
+}
 
 /**
  * Convert sprite priority to y value.
@@ -792,7 +821,7 @@ int16 GfxMgr::priorityToY(int16 priority) {
 		return (priority - 5) * 12 + 48;
 	}
 
-	// dynamic priority bands were introduced in 3.002.086 (effectively AGI3)
+	// dynamic priority bands were introduced in 2.936 (effectively last version of AGI2)
 	// It seems there was a glitch, that caused priority bands to not get calculated properly.
 	// It was caused by this function starting with Y = 168 instead of 167, which meant it always
 	// returned with 168 as result.
diff --git a/engines/agi/graphics.h b/engines/agi/graphics.h
index 6f6a1656f4..3f94b3e950 100644
--- a/engines/agi/graphics.h
+++ b/engines/agi/graphics.h
@@ -140,8 +140,14 @@ public:
 	void updateScreen();
 
 	void initPriorityTable();
+	void createDefaultPriorityTable(uint8 *priorityTable);
 	void setPriorityTable(int16 priorityBase);
-	void setPriority(int16 yPos, int16 priority);
+	bool saveLoadWasPriorityTableModified();
+	int16 saveLoadGetPriority(int16 yPos);
+	void saveLoadSetPriorityTableModifiedBool(bool wasModified);
+	void saveLoadSetPriority(int16 yPos, int16 priority);
+	void saveLoadFigureOutPriorityTableModifiedBool();
+
 	int16 priorityToY(int16 priority);
 	int16 priorityFromY(int16 yPos);
 };
diff --git a/engines/agi/op_cmd.cpp b/engines/agi/op_cmd.cpp
index 4339bf2712..8b24d250b1 100644
--- a/engines/agi/op_cmd.cpp
+++ b/engines/agi/op_cmd.cpp
@@ -2180,6 +2180,12 @@ void cmdPushScript(AgiGame *state, AgiEngine *vm, uint8 *parameter) {
 }
 
 void cmdSetPriBase(AgiGame *state, AgiEngine *vm, uint8 *parameter) {
+	if (getVersion() < 0x2936) {
+		// was not available before 2.936 (last AGI2 version)
+		warning("set.pri.base called, although not available for current AGI version");
+		return;
+	}
+
 	uint16 priorityBase = parameter[0];
 
 	debug(0, "Priority base set to %d", priorityBase);
diff --git a/engines/agi/opcodes.cpp b/engines/agi/opcodes.cpp
index 359d79ee4a..78beb475ee 100644
--- a/engines/agi/opcodes.cpp
+++ b/engines/agi/opcodes.cpp
@@ -347,9 +347,9 @@ AgiInstruction insV2[] = {
 	{ "push.script",        "",         &cmdPushScript },       // BB
 	{ "pop.script",         "",         &cmdPopScript },        // BC
 	{ "hold.key",           "",         &cmdHoldKey },          // BD
-	{ "set.pri.base",       "n",        &cmdSetPriBase },       // BE
+	{ "set.pri.base",       "n",        &cmdSetPriBase },       // BE // AGI2.936+
 	{ "discard.sound",      "n",        &cmdDiscardSound },     // BF
-	{ "hide.mouse",         "",         &cmdHideMouse }, // 1 arg for AGI version 3.002.086
+	{ "hide.mouse",         "",         &cmdHideMouse }, // 1 arg for AGI version 3.002.086 AGI3+ only starts here
 	{ "allow.menu",         "n",        &cmdAllowMenu },        // C1
 	{ "show.mouse",         "",         &cmdShowMouse },        // C2
 	{ "fence.mouse",        "nnnn",     &cmdFenceMouse },       // C3
diff --git a/engines/agi/saveload.cpp b/engines/agi/saveload.cpp
index e22b127021..5f1c5112cd 100644
--- a/engines/agi/saveload.cpp
+++ b/engines/agi/saveload.cpp
@@ -45,24 +45,25 @@
 #include "agi/systemui.h"
 #include "agi/words.h"
 
-#define SAVEGAME_CURRENT_VERSION 9
+#define SAVEGAME_CURRENT_VERSION 10
 
 //
-// Version 0 (Sarien): view table has 64 entries
-// Version 1 (Sarien): view table has 256 entries (needed in KQ3)
-// Version 2 (ScummVM): first ScummVM version
-// Version 3 (ScummVM): added AGIPAL save/load support
-// Version 4 (ScummVM): added thumbnails and save creation date/time
-// Version 5 (ScummVM): Added game md5
-// Version 6 (ScummVM): Added game played time
-// Version 7 (ScummVM): Added controller key mappings
-//                       required for some games for quick-loading from ScummVM main menu
-//                       for games, that do not set all key mappings right at the start
-//                      Added automatic save data (for command SetSimple)
-// Version 8 (ScummVM): Added Hold-Key-Mode boolean
-//                       required for at least Mixed Up Mother Goose
-//                       gets set at the start of the game only
-// Version 9 (ScummVM): Added seconds to saved game time stamp
+// Version 0 (Sarien):   view table has 64 entries
+// Version 1 (Sarien):   view table has 256 entries (needed in KQ3)
+// Version 2 (ScummVM):  first ScummVM version
+// Version 3 (ScummVM):  added AGIPAL save/load support
+// Version 4 (ScummVM):  added thumbnails and save creation date/time
+// Version 5 (ScummVM):  Added game md5
+// Version 6 (ScummVM):  Added game played time
+// Version 7 (ScummVM):  Added controller key mappings
+//                        required for some games for quick-loading from ScummVM main menu
+//                        for games, that do not set all key mappings right at the start
+//                       Added automatic save data (for command SetSimple)
+// Version 8 (ScummVM):  Added Hold-Key-Mode boolean
+//                        required for at least Mixed Up Mother Goose
+//                        gets set at the start of the game only
+// Version 9 (ScummVM):  Added seconds to saved game time stamp
+// Version 10 (ScummVM): Added priorityTableSet boolean
 
 namespace Agi {
 
@@ -174,9 +175,11 @@ int AgiEngine::saveGame(const Common::String &fileName, const Common::String &de
 		out->writeSint16BE(0);
 	}
 
-	// TODO: save if priority table was modified
 	for (i = 0; i < SCRIPT_HEIGHT; i++)
-		out->writeByte(_gfx->priorityFromY(i));
+		out->writeByte(_gfx->saveLoadGetPriority(i));
+
+	// Version 10+: Save, if priority table got modified (set.pri.base opcode)
+	out->writeSint16BE((int16)_gfx->saveLoadWasPriorityTableModified());
 
 	out->writeSint16BE((int16)_game.gfxMode);
 	out->writeByte(_text->inputGetCursorChar());
@@ -500,7 +503,21 @@ int AgiEngine::loadGame(const Common::String &fileName, bool checkId) {
 	}
 
 	for (i = 0; i < SCRIPT_HEIGHT; i++)
-		_gfx->setPriority(i, in->readByte());
+		_gfx->saveLoadSetPriority(i, in->readByte());
+
+	if (saveVersion >= 10) {
+		// Version 10+: priority table was modified by scripts
+		int16 priorityTableWasModified = in->readSint16BE();
+
+		if (priorityTableWasModified) {
+			_gfx->saveLoadSetPriorityTableModifiedBool(true);
+		} else {
+			_gfx->saveLoadSetPriorityTableModifiedBool(false);
+		}
+	} else {
+		// Try to figure it out by ourselves
+		_gfx->saveLoadFigureOutPriorityTableModifiedBool();
+	}
 
 	_text->closeWindow();