replaced many unsafe uses of derefActorSafe by derefActor; replaced derefActorSafe/assert pairs by derefActor (gives better error message); replaced various derefActorSafe/if(a!=0) pairs by derefActor (in cases where the deref should never fail, ever, except due to a bug in ScummVM)

svn-id: r7859

8 files changed, 114 insertions, 250 deletions

diff --git a/scumm/akos.cpp b/scumm/akos.cpp
index bf4f4500cd..cfced1bc87 100644
--- a/scumm/akos.cpp
+++ b/scumm/akos.cpp
@@ -1464,7 +1464,7 @@ bool Scumm::akos_increaseAnim(Actor *a, int chan, byte *aksq, uint16 *akfo, int
 
 		switch (code) {
 		case AKC_StartAnimInActor:
-			akos_queCommand(4, derefActorSafe(a->getAnimVar(GB(2)), "akos_increaseAnim:29"), a->getAnimVar(GB(3)), 0);
+			akos_queCommand(4, derefActor(a->getAnimVar(GB(2)), "akos_increaseAnim:29"), a->getAnimVar(GB(3)), 0);
 			continue;
 
 		case AKC_Random:
@@ -1510,7 +1510,7 @@ bool Scumm::akos_increaseAnim(Actor *a, int chan, byte *aksq, uint16 *akfo, int
 			akos_queCommand(4, a, a->getAnimVar(GB(2)), 0);
 			continue;
 		case AKC_SetVarInActor:
-			derefActorSafe(a->getAnimVar(GB(2)), "akos_increaseAnim:9")->setAnimVar(GB(3), GW(4));
+			derefActor(a->getAnimVar(GB(2)), "akos_increaseAnim:9")->setAnimVar(GB(3), GW(4));
 			continue;
 		case AKC_HideActor:
 			akos_queCommand(1, a, 0, 0);
diff --git a/scumm/gfx.cpp b/scumm/gfx.cpp
index 50fc505d51..f59dfae6bf 100644
--- a/scumm/gfx.cpp
+++ b/scumm/gfx.cpp
@@ -665,7 +665,7 @@ void Scumm::drawFlashlight() {
 		x = _virtualMouse.x;
 		y = _virtualMouse.y;
 	} else {
-		Actor *a = a = derefActorSafe(VAR(VAR_EGO), "drawFlashlight");
+		Actor *a = derefActor(VAR(VAR_EGO), "drawFlashlight");
 		x = a->x;
 		y = a->y;
 	}
@@ -2062,7 +2062,6 @@ void Scumm::setCameraAt(int pos_x, int pos_y) {
 }
 
 void Scumm::setCameraFollows(Actor *a) {
-	assert(a != NULL);
 
 	if (_features & GF_AFTER_V7) {
 		byte oldfollow = camera._follows;
@@ -2103,9 +2102,8 @@ void Scumm::setCameraFollows(Actor *a) {
 			setCameraAt(a->x, 0);
 
 		for (i = 1; i < _numActors; i++) {
-			a = derefActor(i);
-			if (a->isInCurrentRoom())
-				a->needRedraw = true;
+			if (_actors[i].isInCurrentRoom())
+				_actors[i].needRedraw = true;
 		}
 		runHook(0);
 	}
@@ -2131,7 +2129,7 @@ void Scumm::moveCamera() {
 		Actor *a = NULL;
 
 		if (camera._follows) {
-			a = derefActorSafe(camera._follows, "moveCamera");
+			a = derefActor(camera._follows, "moveCamera");
 			if (abs(camera._cur.x - a->x) > VAR(VAR_CAMERA_THRESHOLD_X) ||
 					abs(camera._cur.y - a->y) > VAR(VAR_CAMERA_THRESHOLD_Y)) {
 				camera._movingToActor = true;
@@ -2234,7 +2232,7 @@ void Scumm::moveCamera() {
 		}
 
 		if (camera._mode == CM_FOLLOW_ACTOR) {
-			a = derefActorSafe(camera._follows, "moveCamera");
+			a = derefActor(camera._follows, "moveCamera");
 
 			actorx = a->x;
 			t = (actorx >> 3) - _screenStartStrip;
@@ -2251,7 +2249,7 @@ void Scumm::moveCamera() {
 		}
 
 		if (camera._movingToActor) {
-			a = derefActorSafe(camera._follows, "moveCamera(2)");
+			a = derefActor(camera._follows, "moveCamera(2)");
 			camera._dest.x = a->x;
 		}
 
@@ -2344,7 +2342,7 @@ void Scumm::actorFollowCamera(int act) {
 		}
 
 		old = camera._follows;
-		setCameraFollows(derefActorSafe(act, "actorFollowCamera"));
+		setCameraFollows(derefActor(act, "actorFollowCamera"));
 		if (camera._follows != old)
 			runHook(0);
 
diff --git a/scumm/object.cpp b/scumm/object.cpp
index c803dac960..42a7f12497 100644
--- a/scumm/object.cpp
+++ b/scumm/object.cpp
@@ -879,7 +879,7 @@ byte *Scumm::getObjOrActorName(int obj) {
 	int i;
 
 	if (obj < _numActors)
-		return derefActorSafe(obj, "getObjOrActorName")->getActorName();
+		return derefActor(obj, "getObjOrActorName")->getActorName();
 
 	if (_features & GF_SMALL_HEADER) {
 		byte offset = 0;
@@ -1179,7 +1179,7 @@ int Scumm::getObjX(int obj) {
 	if (obj < _numActors) {
 		if (obj < 1)
 			return 0;									/* fix for indy4's map */
-		return derefActorSafe(obj, "getObjX")->x;
+		return derefActor(obj, "getObjX")->x;
 	} else {
 		if (whereIsObject(obj) == WIO_NOT_FOUND)
 			return -1;
@@ -1193,7 +1193,7 @@ int Scumm::getObjY(int obj) {
 	if (obj < _numActors) {
 		if (obj < 1)
 			return 0;									/* fix for indy4's map */
-		return derefActorSafe(obj, "getObjY")->y;
+		return derefActor(obj, "getObjY")->y;
 	} else {
 		if (whereIsObject(obj) == WIO_NOT_FOUND)
 			return -1;
@@ -1210,7 +1210,7 @@ int Scumm::getObjOldDir(int obj) {
 int Scumm::getObjNewDir(int obj) {
 	int dir;
 	if (obj < _numActors) {
-		dir = derefActorSafe(obj, "getObjNewDir")->facing;
+		dir = derefActor(obj, "getObjNewDir")->facing;
 	} else {
 		int x, y;
 		getObjectXYPos(obj, x, y, dir);
@@ -1276,7 +1276,7 @@ int Scumm::getDistanceBetween(bool is_obj_1, int b, int c, bool is_obj_2, int e,
 		if (getObjectOrActorXY(b, x, y) == -1)
 			return -1;
 		if (b < _numActors)
-			i = derefActorSafe(b, "unkObjProc1")->scalex;
+			i = derefActor(b, "unkObjProc1")->scalex;
 	} else {
 		x = b;
 		y = c;
@@ -1286,7 +1286,7 @@ int Scumm::getDistanceBetween(bool is_obj_1, int b, int c, bool is_obj_2, int e,
 		if (getObjectOrActorXY(e, x2, y2) == -1)
 			return -1;
 		if (e < _numActors)
-			j = derefActorSafe(e, "unkObjProc1(2)")->scalex;
+			j = derefActor(e, "unkObjProc1(2)")->scalex;
 	} else {
 		x2 = e;
 		y2 = f;
diff --git a/scumm/script_v2.cpp b/scumm/script_v2.cpp
index c9d4353cbb..8fc7a0e26f 100644
--- a/scumm/script_v2.cpp
+++ b/scumm/script_v2.cpp
@@ -642,8 +642,7 @@ void Scumm_v2::o2_subtract() {
 }
 
 void Scumm_v2::o2_waitForActor() {
-	Actor *a = derefActorSafe(getVarOrDirectByte(0x80), "o2_waitForActor");
-	assert(a);
+	Actor *a = derefActor(getVarOrDirectByte(0x80), "o2_waitForActor");
 	if (a->moving) {
 		_scriptPointer -= 2;
 		o5_breakHere();
@@ -679,8 +678,7 @@ void Scumm_v2::o2_actorSet() {
 		return;
 	}
 	
-	a = derefActorSafe(act, "actorSet");
-	assert(a);
+	a = derefActor(act, "actorSet");
 
 	switch (_opcode) {
 		case 1: 	// Actor Sound
@@ -989,8 +987,7 @@ void Scumm_v2::o2_ifClassOfIs() {
 void Scumm_v2::o2_walkActorTo() {
 	int x, y;
 	Actor *a;
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o2_walkActorTo");
-	assert(a);
+	a = derefActor(getVarOrDirectByte(0x80), "o2_walkActorTo");
 
 	x = getVarOrDirectByte(0x40) * 8;
 	y = getVarOrDirectByte(0x20) * 2;
@@ -1003,8 +1000,7 @@ void Scumm_v2::o2_putActor() {
 	int x, y;
 	Actor *a;
 
-	a = derefActorSafe(act, "o2_putActor");
-	assert(a);
+	a = derefActor(act, "o2_putActor");
 
 	x = getVarOrDirectByte(0x40) * 8;
 	y = getVarOrDirectByte(0x20) * 2;
@@ -1025,8 +1021,7 @@ void Scumm_v2::o2_walkActorToObject() {
 	int obj;
 	Actor *a;
 
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o2_walkActorToObject");
-	assert(a);
+	a = derefActor(getVarOrDirectByte(0x80), "o2_walkActorToObject");
 	obj = getVarOrDirectWord(0x40);
 	if (whereIsObject(obj) != WIO_NOT_FOUND) {
 		int x, y, dir;
@@ -1039,8 +1034,7 @@ void Scumm_v2::o2_putActorAtObject() {
 	int obj, x, y;
 	Actor *a;
 
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o2_putActorAtObject");
-	assert(a);
+	a = derefActor(getVarOrDirectByte(0x80), "o2_putActorAtObject");
 
 	obj = getVarOrDirectByte(0x40);
 	if (whereIsObject(obj) != WIO_NOT_FOUND)
@@ -1057,8 +1051,7 @@ void Scumm_v2::o2_setActorElevation() {
 	int act = getVarOrDirectByte(0x80);
 	int elevation = getVarOrDirectByte(0x40);
 
-	Actor *a = derefActorSafe(act, "o2_setActorElevation");
-	assert(a);
+	Actor *a = derefActor(act, "o2_setActorElevation");
 	a->elevation = elevation;
 }
 
@@ -1066,8 +1059,7 @@ void Scumm_v2::o2_animateActor() {
 	int act = getVarOrDirectByte(0x80);
 	int anim = getVarOrDirectByte(0x40);
 
-	Actor *a = derefActorSafe(act, "o2_animateActor");
-	assert(a);
+	Actor *a = derefActor(act, "o2_animateActor");
 	a->animateActor(anim);
 }
 
@@ -1117,8 +1109,7 @@ void Scumm_v2::o2_loadRoomWithEgo() {
 	obj = getVarOrDirectWord(0x80);
 	room = getVarOrDirectByte(0x40);
 
-	a = derefActorSafe(VAR(VAR_EGO), "o2_loadRoomWithEgo");
-	assert(a);
+	a = derefActor(VAR(VAR_EGO), "o2_loadRoomWithEgo");
 
 	a->putActor(0, 0, room);
 	_egoPositioned = false;
@@ -1368,8 +1359,7 @@ void Scumm_v2::o2_cursorCommand() {	// TODO: Define the magic numbers
 void Scumm_v2::o2_getActorWalkBox() {
 	Actor *a;
 	getResultPos();
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o2_getActorWalkbox");
-	assert(a);
+	a = derefActor(getVarOrDirectByte(0x80), "o2_getActorWalkbox");
 	setResult(a->walkbox);
 }
 
diff --git a/scumm/script_v5.cpp b/scumm/script_v5.cpp
index 3f332e75e4..bef146cf0c 100644
--- a/scumm/script_v5.cpp
+++ b/scumm/script_v5.cpp
@@ -412,8 +412,7 @@ void Scumm_v5::o5_actorSet() {
 			ss->number, _scriptPointer - _scriptOrgPointer);
 	}
 
-	a = derefActorSafe(act, "actorSet");
-	assert(a);
+	a = derefActor(act, "o5_actorSet");
 
 	while ((_opcode = fetchScriptByte()) != 0xFF) {
 		if (_features & GF_SMALL_HEADER)
@@ -545,8 +544,7 @@ void Scumm_v5::o5_setClass() {
 			// Class '0' means: clean all class data
 			_classData[obj] = 0;
 			if ((_features & GF_SMALL_HEADER) && obj <= _numActors) {
-				Actor *a = derefActorSafe(obj, "setClass");
-				assert(a);
+				Actor *a = derefActor(obj, "o5_setClass");
 				a->ignoreBoxes = false;
 				a->forceClip = 0;
 			}
@@ -572,13 +570,7 @@ void Scumm_v5::o5_and() {
 void Scumm_v5::o5_animateActor() {
 	int act = getVarOrDirectByte(0x80);
 	int anim = getVarOrDirectByte(0x40);
-
-	Actor *a = derefActorSafe(act, "o5_animateActor");
-	if (!a) {
-		warning("Invalid actor %d in o5_animateActor", act);
-		return;
-	}
-
+	Actor *a = derefActor(act, "o5_animateActor");
 	a->animateActor(anim);
 }
 
@@ -890,17 +882,9 @@ void Scumm_v5::o5_expression() {
 }
 
 void Scumm_v5::o5_faceActor() {
-	int act, obj;
-	Actor *a;
-	act = getVarOrDirectByte(0x80);
-	obj = getVarOrDirectWord(0x40);
-
-	a = derefActorSafe(act, "o5_faceActor");
-	if (!a) {
-		warning("Invalid actor %d in o5_faceActor", act);
-		return;
-	}
-
+	int act = getVarOrDirectByte(0x80);
+	int obj = getVarOrDirectWord(0x40);
+	Actor *a = derefActor(act, "o5_faceActor");
 	a->faceToObject(obj);
 }
 
@@ -928,82 +912,37 @@ void Scumm_v5::o5_freezeScripts() {
 }
 
 void Scumm_v5::o5_getActorCostume() {
-	int act;
-	Actor *a;
 	getResultPos();
-	act = getVarOrDirectByte(0x80);
-
-	a = derefActorSafe(act, "o5_getActorCostume");
-	if (!a) {
-		warning("Invalid actor %d in o5_getActorCostume", act);
-		setResult(0);
-		return;
-	}
-
+	int act = getVarOrDirectByte(0x80);
+	Actor *a = derefActor(act, "o5_getActorCostume");
 	setResult(a->costume);
 }
 
 void Scumm_v5::o5_getActorElevation() {
-	int act;
-	Actor *a;
 	getResultPos();
-	act = getVarOrDirectByte(0x80);
-
-	a = derefActorSafe(act, "o5_getActorElevation");
-	if (!a) {
-		warning("Invalid actor %d in o5_getActorElevation", act);
-		setResult(0);
-		return;
-	}
-
+	int act = getVarOrDirectByte(0x80);
+	Actor *a = derefActor(act, "o5_getActorElevation");
 	setResult(a->elevation);
 }
 
 void Scumm_v5::o5_getActorFacing() {
-	int act;
-	Actor *a;
 	getResultPos();
-	act = getVarOrDirectByte(0x80);
-
-	a = derefActorSafe(act, "o5_getActorFacing");
-	if (!a) {
-		warning("Invalid actor %d in o5_getActorFacing", act);
-		setResult(0);
-		return;
-	}
-
+	int act = getVarOrDirectByte(0x80);
+	Actor *a = derefActor(act, "o5_getActorFacing");
 	setResult(newDirToOldDir(a->facing));
 }
 
 void Scumm_v5::o5_getActorMoving() {
-	int act;
-	Actor *a;
 	getResultPos();
-	act = getVarOrDirectByte(0x80);
-
-	a = derefActorSafe(act, "o5_getActorMoving");
-	if (!a) {
-		warning("Invalid actor %d in o5_getActorMoving", act);
-		setResult(0);
-		return;
-	}
-
+	int act = getVarOrDirectByte(0x80);
+	Actor *a = derefActor(act, "o5_getActorMoving");
 	setResult(a->moving);
 }
 
 void Scumm_v5::o5_getActorRoom() {
-	int act;
-	Actor *a;
 	getResultPos();
-	act = getVarOrDirectByte(0x80);
-
-	a = derefActorSafe(act, "o5_getActorRoom");
-	if (!a) {
-		warning("Invalid actor %d in o5_getActorRoom", act);
-		setResult(0);
-		return;
-	}
-
+	int act = getVarOrDirectByte(0x80);
+	Actor *a = derefActor(act, "o5_getActorRoom");
 	setResult(a->room);
 }
 
@@ -1017,8 +956,7 @@ void Scumm_v5::o5_getActorScale() {
 	// INDY3 uses this opcode as a wait_for_actor();
 	if ((_gameId == GID_INDY3_256) || (_gameId == GID_INDY3)) {
 		const byte *oldaddr = _scriptPointer - 1;
-		a = derefActorSafe(getVarOrDirectByte(0x80), "o5_getActorScale (wait)");
-		assert(a);
+		a = derefActor(getVarOrDirectByte(0x80), "o5_getActorScale (wait)");
 		if (a->moving) {
 			_scriptPointer = oldaddr;
 			o5_breakHere();
@@ -1027,32 +965,22 @@ void Scumm_v5::o5_getActorScale() {
 	}
 
 	getResultPos();
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o5_getActorScale");
-	assert(a);
+	int act = getVarOrDirectByte(0x80);
+	a = derefActor(act, "o5_getActorScale");
 	setResult(a->scalex);
 }
 
 void Scumm_v5::o5_getActorWalkBox() {
-	int act;
-	Actor *a;
 	getResultPos();
-	act = getVarOrDirectByte(0x80);
-
-	a = derefActorSafe(act, "o5_getActorWalkbox");
-	if (!a) { // FIXME - bug 572977 workaround
-		warning("Invalid actor %d in o5_getActorWalkbox", act);
-		setResult(0);
-		return;
-	}
-
+	int act = getVarOrDirectByte(0x80);
+	Actor *a = derefActor(act, "o5_getActorWalkBox");
 	setResult(a->walkbox);
 }
 
 void Scumm_v5::o5_getActorWidth() {
-	Actor *a;
 	getResultPos();
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o5_getActorWidth");
-	assert(a);
+	int act = getVarOrDirectByte(0x80);
+	Actor *a = derefActor(act, "o5_getActorWidth");
 	setResult(a->width);
 }
 
@@ -1087,18 +1015,9 @@ void Scumm_v5::o5_getActorY() {
 }
 
 void Scumm_v5::o5_getAnimCounter() {
-	int act;
-	Actor *a;
 	getResultPos();
-	act = getVarOrDirectByte(0x80);
-
-	a = derefActorSafe(act, "o5_getAnimCounter");
-	if (!a) {
-		warning("Invalid actor %d in o5_getAnimCounter", act);
-		setResult(0);
-		return;
-	}
-
+	int act = getVarOrDirectByte(0x80);
+	Actor *a = derefActor(act, "o5_getAnimCounter");
 	setResult(a->cost.animCounter1);
 }
 
@@ -1229,12 +1148,9 @@ void Scumm_v5::o5_increment() {
 }
 
 void Scumm_v5::o5_isActorInBox() {
-	int box;
-	Actor *a;
-
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o5_isActorInBox");
-	assert(a);
-	box = getVarOrDirectByte(0x40);
+	int act = getVarOrDirectByte(0x80);
+	int box = getVarOrDirectByte(0x40);
+	Actor *a = derefActor(act, "o5_isActorInBox");
 
 	if (!checkXYInBoxBounds(box, a->x, a->y))
 		o5_jumpRelative();
@@ -1370,8 +1286,7 @@ void Scumm_v5::o5_loadRoomWithEgo() {
 	obj = getVarOrDirectWord(0x80);
 	room = getVarOrDirectByte(0x40);
 
-	a = derefActorSafe(VAR(VAR_EGO), "o5_loadRoomWithEgo");
-	assert(a);
+	a = derefActor(VAR(VAR_EGO), "o5_loadRoomWithEgo");
 
 	a->putActor(0, 0, room);
 	_egoPositioned = false;
@@ -1502,11 +1417,9 @@ void Scumm_v5::o5_putActor() {
 	int x, y;
 	Actor *a;
 
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o5_putActor");
-	assert(a);
+	a = derefActor(getVarOrDirectByte(0x80), "o5_putActor");
 	x = getVarOrDirectWord(0x40);
 	y = getVarOrDirectWord(0x20);
-
 	a->putActor(x, y, a->room);
 }
 
@@ -1514,8 +1427,7 @@ void Scumm_v5::o5_putActorAtObject() {
 	int obj, x, y;
 	Actor *a;
 
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o5_putActorAtObject");
-	assert(a);
+	a = derefActor(getVarOrDirectByte(0x80), "o5_putActorAtObject");
 	obj = getVarOrDirectWord(0x40);
 	if (whereIsObject(obj) != WIO_NOT_FOUND)
 		getObjectXYPos(obj, x, y);
@@ -1531,12 +1443,7 @@ void Scumm_v5::o5_putActorInRoom() {
 	int act = getVarOrDirectByte(0x80);
 	int room = getVarOrDirectByte(0x40);
 
-	a = derefActorSafe(act, "o5_putActorInRoom");
-
-	if (!a) { // FIXME - yet another null dref hack, see bug 639201
-		warning("Invalid actor %d in o5_putActorInRoom", act);
-		return;
-	}
+	a = derefActor(act, "o5_putActorInRoom");
 
 	if (a->visible && _currentRoom != room && VAR(VAR_TALK_ACTOR) == a->number) {
 		clearMsgQueue();
@@ -2386,8 +2293,8 @@ void Scumm_v5::o5_wait() {
 void Scumm_v5::o5_walkActorTo() {
 	int x, y;
 	Actor *a;
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o5_walkActorTo");
-	assert(a);
+
+	a = derefActor(getVarOrDirectByte(0x80), "o5_walkActorTo");
 	x = getVarOrDirectWord(0x40);
 	y = getVarOrDirectWord(0x20);
 	a->startWalkActor(x, y, -1);
@@ -2405,13 +2312,11 @@ void Scumm_v5::o5_walkActorToActor() {
 		return;
 	}
 
-	a = derefActorSafe(nr, "o5_walkActorToActor");
-	assert(a);
+	a = derefActor(nr, "o5_walkActorToActor");
 	if (!a->isInCurrentRoom())
 		return;
 
-	a2 = derefActorSafe(nr2, "o5_walkActorToActor(2)");
-	assert(a2);
+	a2 = derefActor(nr2, "o5_walkActorToActor(2)");
 	if (!a2->isInCurrentRoom())
 		return;
 
@@ -2434,8 +2339,7 @@ void Scumm_v5::o5_walkActorToObject() {
 	int obj;
 	Actor *a;
 
-	a = derefActorSafe(getVarOrDirectByte(0x80), "o5_walkActorToObject");
-	assert(a);
+	a = derefActor(getVarOrDirectByte(0x80), "o5_walkActorToObject");
 	obj = getVarOrDirectWord(0x40);
 	if (whereIsObject(obj) != WIO_NOT_FOUND) {
 		int x, y, dir;
diff --git a/scumm/script_v6.cpp b/scumm/script_v6.cpp
index 4443e432b3..38b330a15a 100644
--- a/scumm/script_v6.cpp
+++ b/scumm/script_v6.cpp
@@ -951,7 +951,7 @@ void Scumm_v6::o6_panCameraTo() {
 
 void Scumm_v6::o6_actorFollowCamera() {
 	if (_features & GF_AFTER_V7)
-		setCameraFollows(derefActorSafe(pop(), "actorFollowCamera"));
+		setCameraFollows(derefActor(pop(), "actorFollowCamera"));
 	else
 		actorFollowCamera(pop());
 }
@@ -987,15 +987,14 @@ void Scumm_v6::o6_stopScript() {
 }
 
 void Scumm_v6::o6_walkActorToObj() {
-	int obj, dist;
+	int act, obj, dist;
 	Actor *a, *a2;
 	int x;
 
 	dist = pop();
 	obj = pop();
-	a = derefActorSafe(pop(), "o6_walkActorToObj");
-	if (!a)
-		return;
+	act = pop();
+	a = derefActor(act, "o6_walkActorToObj");
 
 	if (obj >= _numActors) {
 		if (whereIsObject(obj) == WIO_NOT_FOUND)
@@ -1004,9 +1003,7 @@ void Scumm_v6::o6_walkActorToObj() {
 		getObjectXYPos(obj, x, y, dir);
 		a->startWalkActor(x, y, dir);
 	} else {
-		a2 = derefActorSafe(obj, "o6_walkActorToObj(2)");
-		if (!a2)
-			return;
+		a2 = derefActor(obj, "o6_walkActorToObj(2)");
 		if (!a->isInCurrentRoom() || !a2->isInCurrentRoom())
 			return;
 		if (dist == 0) {
@@ -1026,21 +1023,19 @@ void Scumm_v6::o6_walkActorTo() {
 	int x, y;
 	y = pop();
 	x = pop();
-	Actor *a = derefActorSafe(pop(), "o6_walkActorTo");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_walkActorTo");
 	a->startWalkActor(x, y, -1);
 }
 
 void Scumm_v6::o6_putActorInRoom() {
-	int room, x, y;
+	int room, x, y, act;
 	Actor *a;
 
 	room = pop();
 	y = pop();
 	x = pop();
-	a = derefActorSafe(pop(), "o6_putActorInRoom");
-	if (!a)
-		return;
+	act = pop();
+	a = derefActor(act, "o6_putActorInRoom");
 
 	if (room == 0xFF || room == 0x7FFFFFFF) {
 		room = a->room;
@@ -1061,7 +1056,7 @@ void Scumm_v6::o6_putActorAtObject() {
 
 	obj = popRoomAndObj(&room);
 
-	a = derefActorSafe(pop(), "o6_putActorAtObject");
+	a = derefActor(pop(), "o6_putActorAtObject");
 	if (whereIsObject(obj) != WIO_NOT_FOUND) {
 		getObjectXYPos(obj, x, y);
 	} else {
@@ -1075,18 +1070,13 @@ void Scumm_v6::o6_putActorAtObject() {
 
 void Scumm_v6::o6_faceActor() {
 	int obj = pop();
-	Actor *a = derefActorSafe(pop(), "o6_faceActor");
-	assert(a);
-
+	Actor *a = derefActor(pop(), "o6_faceActor");
 	a->faceToObject(obj);
 }
 
 void Scumm_v6::o6_animateActor() {
 	int anim = pop();
-	Actor *a = derefActorSafe(pop(), "o6_animateActor");
-	if (!a)
-		return;
-
+	Actor *a = derefActor(pop(), "o6_animateActor");
 	a->animateActor(anim);
 }
 
@@ -1136,9 +1126,7 @@ void Scumm_v6::o6_loadRoomWithEgo() {
 
 	obj = popRoomAndObj(&room);
 
-	a = derefActorSafe(VAR(VAR_EGO), "o6_loadRoomWithEgo");
-	assert(a);
-	
+	a = derefActor(VAR(VAR_EGO), "o6_loadRoomWithEgo");
 	a->putActor(0, 0, room);
 	_egoPositioned = false;
 
@@ -1188,74 +1176,68 @@ void Scumm_v6::o6_isRoomScriptRunning() {
 }
 
 void Scumm_v6::o6_getActorMoving() {
-	Actor *a = derefActorSafe(pop(), "o6_getActorMoving");
-	if (a)
-		push(a->moving);
-	else
-		push(0);
+	Actor *a = derefActor(pop(), "o6_getActorMoving");
+	push(a->moving);
 }
 
 void Scumm_v6::o6_getActorRoom() {
-	Actor *a = derefActorSafe(pop(), "o6_getActorRoom");
-	if (a)
-		push(a->room);
-	else
+	int act = pop();
+	Actor *a = derefActorSafe(act, "o6_getActorRoom");
+	if (!a) {
+		// FIXME: We got called with act = 0. This happens *a lot* in COMI.
+		// But why? Is that just normal, or due to a bug in ScummVM?
+		//warning("Invalid actor %d in o6_getActorRoom", act);
 		push(0);
+		return;
+	}
+
+	push(a->room);
 }
 
 void Scumm_v6::o6_getActorWalkBox() {
-	Actor *a = derefActorSafe(pop(), "o6_getActorWalkBox");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_getActorWalkBox");
 	push(a->ignoreBoxes ? 0 : a->walkbox);
 }
 
 void Scumm_v6::o6_getActorCostume() {
-	Actor *a = derefActorSafe(pop(), "o6_getActorCostume");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_getActorCostume");
 	push(a->costume);
 }
 
 void Scumm_v6::o6_getActorElevation() {
-	Actor *a = derefActorSafe(pop(), "o6_getActorElevation");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_getActorElevation");
 	push(a->elevation);
 }
 
 void Scumm_v6::o6_getActorWidth() {
-	Actor *a = derefActorSafe(pop(), "o6_getActorWidth");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_getActorWidth");
 	push(a->width);
 }
 
 void Scumm_v6::o6_getActorScaleX() {
-	Actor *a = derefActorSafe(pop(), "o6_getActorScale");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_getActorScale");
 	push(a->scalex);
 }
 
 void Scumm_v6::o6_getActorAnimCounter1() {
-	Actor *a = derefActorSafe(pop(), "o6_getActorAnimCounter");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_getActorAnimCounter");
 	push(a->cost.animCounter1);
 }
 
 void Scumm_v6::o6_getAnimateVariable() {
 	int var = pop();
-	Actor *a = derefActorSafe(pop(), "o6_getAnimateVariable");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_getAnimateVariable");
 	push(a->getAnimVar(var));
 }
 
 void Scumm_v6::o6_isActorInBox() {
 	int box = pop();
-	Actor *a = derefActorSafe(pop(), "o6_isActorInBox");
-	assert(a);
+	Actor *a = derefActor(pop(), "o6_isActorInBox");
 	push(checkXYInBoxBounds(box, a->x, a->y));
 }
 
 void Scumm_v6::o6_getActorLayer() {
-	Actor *a = derefActorSafe(pop(), "getActorLayer");
-	assert(a);
+	Actor *a = derefActor(pop(), "getActorLayer");
 	push(a->layer);
 }
 
@@ -2454,10 +2436,10 @@ void Scumm_v6::o6_kernelSetFunctions() {
 			setCursorImg(args[1], (uint) - 1, args[2]);
 			break;
 		case 13:
-			derefActorSafe(args[1], "o6_kernelSetFunctions:14")->remapActorPalette(args[2], args[3], args[4], -1);
+			derefActor(args[1], "o6_kernelSetFunctions:14")->remapActorPalette(args[2], args[3], args[4], -1);
 			break;
 		case 14:
-			derefActorSafe(args[1], "o6_kernelSetFunctions:14")->remapActorPalette(args[2], args[3], args[4], args[5]);
+			derefActor(args[1], "o6_kernelSetFunctions:14")->remapActorPalette(args[2], args[3], args[4], args[5]);
 			break;
 		case 15:
 			_smushFrameRate = args[1];
@@ -2507,7 +2489,7 @@ void Scumm_v6::o6_kernelSetFunctions() {
 			warning("o6_kernelSetFunctions: stub18(%d,%d)", args[1], args[2]);
 			break;
 		case 107:
-			a = derefActorSafe(args[1], "o6_kernelSetFunctions: 107");
+			a = derefActor(args[1], "o6_kernelSetFunctions: 107");
 			a->scalex = (unsigned char)args[2];
 			a->needBgReset = true;
 			a->needRedraw = true;
@@ -2572,7 +2554,7 @@ void Scumm_v6::o6_kernelSetFunctions() {
 			break;
 
 		case 107:									/* set actor scale */
-			a = derefActorSafe(args[1], "o6_kernelSetFunctions: 107");
+			a = derefActor(args[1], "o6_kernelSetFunctions: 107");
 			a->scalex = (unsigned char)args[2];
 			a->needBgReset = true;
 			a->needRedraw = true;
@@ -2589,7 +2571,7 @@ void Scumm_v6::o6_kernelSetFunctions() {
 			break;
 
 		case 111:
-			a = derefActorSafe(args[1], "o6_kernelSetFunctions: 111");
+			a = derefActor(args[1], "o6_kernelSetFunctions: 111");
 			a->shadow_mode = args[2] + args[3];
 			break;
 
@@ -2740,7 +2722,7 @@ void Scumm_v6::o6_kernelGetFunctions() {
 		push(0);
 		break;
 	case 212:
-		a = derefActorSafe(args[1], "o6_kernelGetFunctions:212");
+		a = derefActor(args[1], "o6_kernelGetFunctions:212");
 		// This is used by walk scripts
 		push(a->frame);
 		break;
@@ -2809,7 +2791,7 @@ void Scumm_v6::o6_stampObject() {
 			state = 255;
 		}
 		warning("o6_stampObject: (%d at (%d,%d) scale %d)", object, x, y, state);
-		Actor *a = derefActor(object);
+		Actor *a = derefActor(object, "o6_stampObject");
 		a->scalex = state;
 		a->scaley = state;
 		a->putActor(x, y, _currentRoom); // TODO
diff --git a/scumm/script_v8.cpp b/scumm/script_v8.cpp
index d2f816afa3..56e745abcb 100644
--- a/scumm/script_v8.cpp
+++ b/scumm/script_v8.cpp
@@ -639,8 +639,7 @@ void Scumm_v8::o8_wait() {
 	case 0x1E:		// SO_WAIT_FOR_ACTOR Wait for actor (to finish current action?)
 		offs = fetchScriptWordSigned();
 		actnum = pop();
-		a = derefActorSafe(actnum, "o8_wait:SO_WAIT_FOR_ACTOR");
-		assert(a);
+		a = derefActor(actnum, "o8_wait:SO_WAIT_FOR_ACTOR");
 		if (a->moving) {
 			_scriptPointer += offs;
 			o6_breakHere();
@@ -666,8 +665,7 @@ void Scumm_v8::o8_wait() {
 	case 0x22:		// SO_WAIT_FOR_ANIMATION
 		offs = fetchScriptWordSigned();
 		actnum = pop();
-		a = derefActorSafe(actnum, "o8_wait:SO_WAIT_FOR_ANIMATION");
-		assert(a);
+		a = derefActor(actnum, "o8_wait:SO_WAIT_FOR_ANIMATION");
 		if (a->isInCurrentRoom() && a->needRedraw) {
 			_scriptPointer += offs;
 			o6_breakHere();
@@ -676,8 +674,7 @@ void Scumm_v8::o8_wait() {
 	case 0x23:		// SO_WAIT_FOR_TURN
 		offs = fetchScriptWordSigned();
 		actnum = pop();
-		a = derefActorSafe(actnum, "o8_wait:SO_WAIT_FOR_TURN");
-		assert(a);
+		a = derefActor(actnum, "o8_wait:SO_WAIT_FOR_TURN");
 		if (a->isInCurrentRoom() && a->moving & MF_TURN) {
 			_scriptPointer += offs;
 			o6_breakHere();
@@ -1388,13 +1385,11 @@ void Scumm_v8::o8_kernelSetFunctions() {
 		break;
 	}
 	case 13:	// remapCostume
-		a = derefActorSafe(args[1], "o8_kernelSetFunctions:remapCostume");
-		assert(a);
+		a = derefActor(args[1], "o8_kernelSetFunctions:remapCostume");
 		a->remapActorPalette(args[2], args[3], args[4], -1);
 		break;
 	case 14:	// remapCostumeInsert
-		a = derefActorSafe(args[1], "o8_kernelSetFunctions:remapCostumeInsert");
-		assert(a);
+		a = derefActor(args[1], "o8_kernelSetFunctions:remapCostumeInsert");
 		a->remapActorPalette(args[2], args[3], args[4], args[5]);
 		break;
 	case 15:	// setVideoFrameRate
@@ -1416,8 +1411,7 @@ void Scumm_v8::o8_kernelSetFunctions() {
 		// lipSyncWidth and lipSyncHeight, which we currently don't support. As a result,
 		// actors will currently not move their mouth at all!
 //		warning("o8_kernelSetFunctions: setActorChoreLimbFrame(%d, %d, %d, %d)", args[1], args[2], args[3], args[4]);
-		a = derefActorSafe(args[1], "o8_kernelSetFunctions:setActorChoreLimbFrame");
-		assert(a);
+		a = derefActor(args[1], "o8_kernelSetFunctions:setActorChoreLimbFrame");
 
 		a->startAnimActor(args[2]);
 		a->animateLimb(args[3], args[4]);
@@ -1553,8 +1547,7 @@ void Scumm_v8::o8_kernelGetFunctions() {
 	case 0xD9: {   // actorHit - used, for example, to detect ship collision
 	               // during ship-to-ship combat.
 #if 0
-		Actor *a = derefActorSafe(args[1], "actorHit");
-		assert(a);
+		Actor *a = derefActor(args[1], "actorHit");
 		int x = args[2];
 		int y = args[3];
 		
@@ -1609,8 +1602,7 @@ void Scumm_v8::o8_kernelGetFunctions() {
 		break;
 	case 0xDC:		// actorTalkAnimation
 		{
-		Actor *a = derefActorSafe(args[1], "actorTalkAnimation");
-		assert(a);
+		Actor *a = derefActor(args[1], "actorTalkAnimation");
 		push(a->talkStartFrame);
 		}
 		break;
@@ -1655,8 +1647,7 @@ void Scumm_v8::o8_kernelGetFunctions() {
 
 void Scumm_v8::o8_getActorChore() {
 	int actnum = pop();
-	Actor *a = derefActorSafe(actnum, "o8_getActorChore");
-	assert(a);
+	Actor *a = derefActor(actnum, "o8_getActorChore");
 
 	// FIXME: This is a hack for the cannon scene, as something isn't quite right
 	// here yet..
@@ -1670,8 +1661,7 @@ void Scumm_v8::o8_getActorChore() {
 
 void Scumm_v8::o8_getActorZPlane() {
 	int actnum = pop();
-	Actor *a = derefActorSafe(actnum, "o8_getActorChore");
-	assert(a);
+	Actor *a = derefActor(actnum, "o8_getActorChore");
 
 	int z = a->forceClip;
 	if (z == 100) {
diff --git a/scumm/sound.cpp b/scumm/sound.cpp
index 8520e31c83..bc0bbcb9bb 100644
--- a/scumm/sound.cpp
+++ b/scumm/sound.cpp
@@ -489,7 +489,7 @@ void Sound::processSfxQueues() {
 		
 
 		if (act != 0 && (uint) act < 0x80 && !_scumm->_string[0].no_talk_anim) {
-			a = _scumm->derefActorSafe(act, "processSfxQueues");
+			a = _scumm->derefActor(act, "processSfxQueues");
 			if (a->room == _scumm->_currentRoom && (finished || !_endOfMouthSync)) {
 				b = true;
 				if (!finished)