1 files changed, 38 insertions, 36 deletions

diff --git a/engines/titanic/star_control/dvector.cpp b/engines/titanic/star_control/dvector.cpp
index 0a6fa97d16..8ea167a8be 100644
--- a/engines/titanic/star_control/dvector.cpp
+++ b/engines/titanic/star_control/dvector.cpp
@@ -26,6 +26,9 @@
 
 namespace Titanic {
 
+const double Rad2Deg = 180.0 / M_PI;
+const double Deg2Rad = 1.0 / Rad2Deg;
+
 double DVector::normalize() {
 	double hyp = sqrt(_x * _x + _y * _y + _z * _z);
 	assert(hyp);
@@ -40,18 +43,29 @@ double DVector::getDistance(const DVector &src) {
 	return sqrt((src._x - _x) * (src._x - _x) + (src._y - _y) * (src._y - _y) + (src._z - _z) * (src._z - _z));
 }
 
-DVector DVector::fn1(const DAffine &m) {
+DVector DVector::DAffMatrixProdVec(const DAffine &m) {
 	DVector dest;
-	dest._x = m._col3._x * _z + m._col2._x * _y + m._col1._x * _x + m._col4._x;
-	dest._y = m._col2._y * _y + m._col3._y * _z + m._col1._y * _x + m._col4._y;
-	dest._z = m._col3._z * _z + m._col2._z * _y + m._col1._z * _x + m._col4._z;
+	dest._x = m._col1._x * _x +
+                  m._col2._x * _y +
+                  m._col3._x * _z +
+                  m._col4._x;
+
+	dest._y = m._col1._y * _x +
+                  m._col2._y * _y +
+                  m._col3._y * _z +
+                  m._col4._y;
+
+	dest._z = m._col1._z * _x +
+                  m._col2._z * _y +
+                  m._col3._z * _z +
+                  m._col4._z;
+
 	return dest;
 }
 
-void DVector::fn2(double angle) {
-	const double FACTOR = 2 * M_PI / 360.0;
-	double sinVal = sin(angle * FACTOR);
-	double cosVal = cos(angle * FACTOR);
+void DVector::RotVectAxisY(double angle_deg) {
+	double sinVal = sin(angle_deg * Deg2Rad);
+	double cosVal = cos(angle_deg * Deg2Rad);
 	double x = cosVal * _x - sinVal * _z;
 	double z = cosVal * _z + sinVal * _x;
 
@@ -59,51 +73,39 @@ void DVector::fn2(double angle) {
 	_z = z;
 }
 
-DVector DVector::fn3() const {
+DVector DVector::getAnglesAsVect() const {
 	DVector vector = *this;
 	DVector dest;
-	dest._x = vector.normalize();
-	dest._y = acos(vector._y);
-
-	if (ABS(vector._z) < 0.00001) {
-		if (vector._x < 0.0) {
-			dest._z = 2 * M_PI - (M_PI / 2.0);
-		} else {
-			dest._z = M_PI / 2.0;
-		}
-	} else {
-		dest._z = atan(vector._x / vector._z);
-		if (vector._x < 0.0)
-			dest._z += 2 * M_PI;
-	}
+	dest._x = vector.normalize(); // scale that makes this vector have magnitude=1, also does the scaling
+	dest._y = acos(vector._y);    // radian distance/angle that this vector's y component is from the +y axis,
+                                      // result is restricted to [0,pi]
+	dest._z = atan2(vector._x,vector._z); // result is restricted to [-pi,pi]
 
 	return dest;
 }
 
-DAffine DVector::fn4(const DVector &v) {
-	const double FACTOR = 180.0 / M_PI;
+DAffine DVector::getFrameTransform(const DVector &v) {
 	DAffine matrix1, matrix2, matrix3, matrix4;
 
-	DVector vector1 = fn3();
-	matrix1.setRotationMatrix(X_AXIS, vector1._y * FACTOR);
-	matrix2.setRotationMatrix(Y_AXIS, -(vector1._z * FACTOR));
+	DVector vector1 = getAnglesAsVect();
+	matrix1.setRotationMatrix(X_AXIS, vector1._y * Rad2Deg);
+	matrix2.setRotationMatrix(Y_AXIS, -(vector1._z * Rad2Deg));
 	matrix3 = matrix1.compose(matrix2);
 	matrix4 = matrix3.inverseTransform();
 
-	vector1 = v.fn3();
-	matrix1.setRotationMatrix(X_AXIS, vector1._y * FACTOR);
-	matrix2.setRotationMatrix(Y_AXIS, -(vector1._z * FACTOR));
+	vector1 = v.getAnglesAsVect();
+	matrix1.setRotationMatrix(X_AXIS, vector1._y * Rad2Deg);
+	matrix2.setRotationMatrix(Y_AXIS, -(vector1._z * Rad2Deg));
 	matrix3 = matrix1.compose(matrix2);
 
 	return matrix4.compose(matrix3);
 }
 
-DAffine DVector::fn5() const {
-	const double FACTOR = 180.0 / M_PI;
-	DVector v1 = fn3();
+DAffine DVector::RotXY() const {
+	DVector v1 = getAnglesAsVect();
 	DAffine m1, m2;
-	m1.setRotationMatrix(X_AXIS, v1._y * FACTOR);
-	m2.setRotationMatrix(Y_AXIS, -(v1._z * FACTOR));
+	m1.setRotationMatrix(X_AXIS, v1._y * Rad2Deg);
+	m2.setRotationMatrix(Y_AXIS, -(v1._z * Rad2Deg));
 	return m1.compose(m2);
 }