SCI: Fix pseudo mouse in various SCI1 games like e.g. Larry5

Pseudo mouse was functionality in SCI1+ games, that allowed the
user to control the mouse via keyboard cursor keys.

This new class only worked, when a tiny difference inside
the keyboard driver happened on kMapKeyToDir calls. We previously
tried to enable this behavior depending on cursor type, but
this didn't work correctly (Larry 5 for example was not detected
as such, but had PseudoMouse support).

3 files changed, 66 insertions, 4 deletions

diff --git a/engines/sci/engine/features.cpp b/engines/sci/engine/features.cpp
index a993506f7a..e37a1651ef 100644
--- a/engines/sci/engine/features.cpp
+++ b/engines/sci/engine/features.cpp
@@ -45,6 +45,7 @@ GameFeatures::GameFeatures(SegManager *segMan, Kernel *kernel) : _segMan(segMan)
 	if (!ConfMan.getBool("use_cdaudio"))
 		_usesCdTrack = false;
 	_forceDOSTracks = false;
+	_pseudoMouseAbility = kPseudoMouseAbilityUninitialized;
 }
 
 reg_t GameFeatures::getDetectionAddr(const Common::String &objName, Selector slc, int methodNum) {
@@ -605,4 +606,50 @@ bool GameFeatures::useAltWinGMSound() {
 	}
 }
 
+// PseudoMouse was added during SCI1
+// PseudoMouseAbility is about a tiny difference in the keyboard driver, which sets the event type to either
+// 40h (old behaviour) or 44h (the keyboard driver actually added 40h to the existing value).
+// See engine/kevent.cpp, kMapKeyToDir - also script 933
+
+// SCI1EGA:
+// Quest for Glory 2 still used the old way.
+//
+// SCI1EARLY:
+// King's Quest 5 0.000.062 uses the old way.
+// Leisure Suit Larry 1 demo uses the new way, but no PseudoMouse class.
+// Fairy Tales uses the new way.
+// X-Mas 1990 uses the old way, no PseudoMouse class.
+// Space Quest 4 floppy (1.1) uses the new way.
+// Mixed Up Mother Goose uses the old way, no PseudoMouse class.
+//
+// SCI1MIDDLE:
+// Leisure Suit Larry 5 demo uses the new way.
+// Conquests of the Longbow demo uses the new way.
+// Leisure Suit Larry 1 (2.0) uses the new way.
+// Astro Chicken II uses the new way.
+PseudoMouseAbilityType GameFeatures::detectPseudoMouseAbility() {
+	if (_pseudoMouseAbility == kPseudoMouseAbilityUninitialized) {
+		if (getSciVersion() < SCI_VERSION_1_EARLY) {
+			// SCI1 EGA or earlier -> pseudo mouse ability is always disabled
+			_pseudoMouseAbility = kPseudoMouseAbilityFalse;
+
+		} else if (getSciVersion() == SCI_VERSION_1_EARLY) {
+			// For SCI1 early some games had it enabled, some others didn't.
+			// We try to find an object called "PseudoMouse". If it's found, we enable the ability otherwise we don't.
+			reg_t pseudoMouseAddr = _segMan->findObjectByName("PseudoMouse", 0);
+
+			if (pseudoMouseAddr != NULL_REG) {
+				_pseudoMouseAbility = kPseudoMouseAbilityTrue;
+			} else {
+				_pseudoMouseAbility = kPseudoMouseAbilityFalse;
+			}
+
+		} else {
+			// SCI1 middle or later -> pseudo mouse ability is always enabled
+			_pseudoMouseAbility = kPseudoMouseAbilityTrue;
+		}
+	}
+	return _pseudoMouseAbility;
+}
+
 } // End of namespace Sci
diff --git a/engines/sci/engine/features.h b/engines/sci/engine/features.h
index 1c410267e6..b2d40f400f 100644
--- a/engines/sci/engine/features.h
+++ b/engines/sci/engine/features.h
@@ -34,6 +34,12 @@ enum MoveCountType {
 	kIncrementMoveCount
 };
 
+enum PseudoMouseAbilityType {
+	kPseudoMouseAbilityUninitialized,
+	kPseudoMouseAbilityFalse,
+	kPseudoMouseAbilityTrue
+};
+
 class GameFeatures {
 public:
 	GameFeatures(SegManager *segMan, Kernel *kernel);
@@ -110,6 +116,12 @@ public:
 	 */
 	void forceDOSTracks() { _forceDOSTracks = true; }
 
+	/**
+	 * Autodetects, if Pseudo Mouse ability is enabled (different behavior in keyboard driver)
+	 * @return kPseudoMouseAbilityTrue or kPseudoMouseAbilityFalse
+	 */
+	PseudoMouseAbilityType detectPseudoMouseAbility();
+
 private:
 	reg_t getDetectionAddr(const Common::String &objName, Selector slc, int methodNum = -1);
 
@@ -130,6 +142,8 @@ private:
 	bool _usesCdTrack;
 	bool _forceDOSTracks;
 
+	PseudoMouseAbilityType _pseudoMouseAbility;
+
 	SegManager *_segMan;
 	Kernel *_kernel;
 };
diff --git a/engines/sci/engine/kevent.cpp b/engines/sci/engine/kevent.cpp
index 534d9ce713..d7a716a504 100644
--- a/engines/sci/engine/kevent.cpp
+++ b/engines/sci/engine/kevent.cpp
@@ -258,11 +258,12 @@ reg_t kMapKeyToDir(EngineState *s, int argc, reg_t *argv) {
 	if (readSelectorValue(segMan, obj, SELECTOR(type)) == SCI_EVENT_KEYBOARD) { // Keyboard
 		uint16 message = readSelectorValue(segMan, obj, SELECTOR(message));
 		uint16 eventType = SCI_EVENT_DIRECTION;
-		// Check if the game is using cursor views. These games allowed control
-		// of the mouse cursor via the keyboard controls (the so called
-		// "PseudoMouse" functionality in script 933).
-		if (g_sci->_features->detectSetCursorType() == SCI_VERSION_1_1)
+		// It seems with SCI1 Sierra started to add the SCI_EVENT_DIRECTION bit instead of setting it directly.
+		// It was done inside the keyboard driver and is required for the PseudoMouse functionality and class
+		// to work (script 933).
+		if (g_sci->_features->detectPseudoMouseAbility() == kPseudoMouseAbilityTrue) {
 			eventType |= SCI_EVENT_KEYBOARD;
+		}
 
 		for (int i = 0; i < 9; i++) {
 			if (keyToDirMap[i].key == message) {