Work around a script bug in Full Throttle. See bug #1407789.

svn-id: r20080

4 files changed, 17 insertions, 3 deletions

diff --git a/scumm/actor.cpp b/scumm/actor.cpp
index e892c78248..be84e3f01d 100644
--- a/scumm/actor.cpp
+++ b/scumm/actor.cpp
@@ -909,12 +909,16 @@ void ScummEngine::playActorSounds() {
 	}
 }
 
+bool ScummEngine::isValidActor(int id) const {
+	return id >= 0 && id < _numActors && _actors[id]._number == id;
+}
+
 Actor *ScummEngine::derefActor(int id, const char *errmsg) const {
 	if (id == 0)
 		debugC(DEBUG_ACTORS, "derefActor(0, \"%s\") in script %d, opcode 0x%x",
 			errmsg, vm.slot[_currentScript].number, _opcode);
 
-	if (id < 0 || id >= _numActors || _actors[id]._number != id) {
+	if (!isValidActor(id)) {
 		if (errmsg)
 			error("Invalid actor %d in %s", id, errmsg);
 		else
@@ -928,7 +932,7 @@ Actor *ScummEngine::derefActorSafe(int id, const char *errmsg) const {
 		debugC(DEBUG_ACTORS, "derefActorSafe(0, \"%s\") in script %d, opcode 0x%x",
 			errmsg, vm.slot[_currentScript].number, _opcode);
 
-	if (id < 0 || id >= _numActors || _actors[id]._number != id) {
+	if (!isValidActor(id)) {
 		debugC(DEBUG_ACTORS, "Invalid actor %d in %s (script %d, opcode 0x%x)",
 			 id, errmsg, vm.slot[_currentScript].number, _opcode);
 		return NULL;
diff --git a/scumm/script.cpp b/scumm/script.cpp
index 534d34074e..f74571f6db 100644
--- a/scumm/script.cpp
+++ b/scumm/script.cpp
@@ -1083,6 +1083,14 @@ void ScummEngine::checkAndRunSentenceScript() {
 		localParamList[0] = _sentence[_sentenceNum].verb;
 		localParamList[1] = _sentence[_sentenceNum].objectA;
 		localParamList[2] = _sentence[_sentenceNum].objectB;
+
+		// WORKAROUND for bug #1407789. The script clearly assumes that
+		// one of the two objects is an actor. If that's not the case,
+		// fall back on what appears to be the usual sentence script.
+
+		if (_gameId == GID_FT && sentenceScript == 103 && !isValidActor(localParamList[1]) && !isValidActor(localParamList[2])) {
+			sentenceScript = 28;
+		}
 	}
 	_currentScript = 0xFF;
 	if (sentenceScript)
diff --git a/scumm/script_v5.cpp b/scumm/script_v5.cpp
index 382d0f28f0..a55094614b 100644
--- a/scumm/script_v5.cpp
+++ b/scumm/script_v5.cpp
@@ -1052,7 +1052,7 @@ void ScummEngine_v5::o5_getActorRoom() {
 	// WORKAROUND bug #746349. This is a really odd bug in either the script
 	// or in our script engine. Might be a good idea to investigate this
 	// further by e.g. looking at the FOA engine a bit closer.
-	if (_gameId == GID_INDY4 && _roomResource == 94 && vm.slot[_currentScript].number == 206 && act > _numActors) {
+	if (_gameId == GID_INDY4 && _roomResource == 94 && vm.slot[_currentScript].number == 206 && !isValidActor(act)) {
 		setResult(0);
 		return;
 	}
diff --git a/scumm/scumm.h b/scumm/scumm.h
index a59d4f9ccd..437e15f6c9 100644
--- a/scumm/scumm.h
+++ b/scumm/scumm.h
@@ -848,6 +848,8 @@ protected:
 	void setVerbObject(uint room, uint object, uint verb);
 
 public:
+	bool isValidActor(int id) const;
+
 	/* Should be in Actor class */
 	Actor *derefActor(int id, const char *errmsg = 0) const;
 	Actor *derefActorSafe(int id, const char *errmsg) const;