3 files changed, 6 insertions, 7 deletions
diff --git a/engines/titanic/star_control/dvector.cpp b/engines/titanic/star_control/dvector.cpp
index 0dab5bbbcb..55030d243c 100644
--- a/engines/titanic/star_control/dvector.cpp
+++ b/engines/titanic/star_control/dvector.cpp
@@ -77,7 +77,7 @@ DVector DVector::fn3() const {
 	return dest;
 }
 
-void DVector::fn4(const DVector &v, DMatrix &m) {
+DMatrix DVector::fn4(const DVector &v) {
 	const double FACTOR = 180.0 / M_PI;
 	DMatrix matrix1, matrix2, matrix3, matrix4;
 	DMatrix dest;
@@ -94,7 +94,7 @@ void DVector::fn4(const DVector &v, DMatrix &m) {
 	matrix3 = matrix1.fn4(matrix2);
 	matrix4 = matrix1.fn1();
 
-	m = matrix4.fn4(matrix3);
+	return matrix4.fn4(matrix3);
 }
 
 DMatrix DVector::fn5() const {
diff --git a/engines/titanic/star_control/dvector.h b/engines/titanic/star_control/dvector.h
index d9672065bf..cb0d8fb4ee 100644
--- a/engines/titanic/star_control/dvector.h
+++ b/engines/titanic/star_control/dvector.h
@@ -51,7 +51,7 @@ public:
 	DVector *fn1(DVector &dest, const DMatrix &m);
 	void fn2(double val);
 	DVector fn3() const;
-	void fn4(const DVector &v, DMatrix &m);
+	DMatrix fn4(const DVector &v);
 	DMatrix fn5() const;
 
 	/**
diff --git a/engines/titanic/star_control/star_control_sub21.cpp b/engines/titanic/star_control/star_control_sub21.cpp
index 86109a11ac..2dc90d503f 100644
--- a/engines/titanic/star_control/star_control_sub21.cpp
+++ b/engines/titanic/star_control/star_control_sub21.cpp
@@ -47,11 +47,10 @@ void CStarControlSub21::proc10(const FVector &v1, const FVector &v2, const FVect
 
 	DVector vector1 = v1;
 	DVector vector2 = v2;
-	DMatrix matrix1, matrix2 = m, matrix3;
-	vector2.fn4(vector1, matrix1);
-	FMatrix matrix4 = matrix1.fn4(matrix2);
+	DMatrix matrix1 = vector2.fn4(vector1);
+	FMatrix matrix2 = matrix1.fn4(m);
 
-	_sub24.proc3(m, matrix4);
+	_sub24.proc3(m, matrix2);
 	incLockCount();
 }