TITANIC: Change fpose Yaxis rotation to be same as wikipedia

Add negatives to star camera turning rotations so view turns correctly
when no stars are marked and 1 star is marked.

3 files changed, 10 insertions, 4 deletions

diff --git a/engines/titanic/star_control/fpose.cpp b/engines/titanic/star_control/fpose.cpp
index 3f7b03df85..98de447e85 100644
--- a/engines/titanic/star_control/fpose.cpp
+++ b/engines/titanic/star_control/fpose.cpp
@@ -83,6 +83,7 @@ void FPose::identity() {
 	_vector.clear();
 }
 
+// Source: https://en.wikipedia.org/wiki/Rotation_matrix
 void FPose::setRotationMatrix(Axis axis, float amount) {
 	const float ROTATION = 2 * M_PI / 360.0;
 	float sinVal = sin(amount * ROTATION);
@@ -104,11 +105,11 @@ void FPose::setRotationMatrix(Axis axis, float amount) {
 	case Y_AXIS:
 		_row1._x = cosVal;
 		_row1._y = 0.0;
-		_row1._z = sinVal;
+		_row1._z = -sinVal;
 		_row2._x = 0.0;
 		_row2._y = 1.0;
 		_row2._z = 0.0;
-		_row3._x = -sinVal;
+		_row3._x = sinVal;
 		_row3._y = 0.0;
 		_row3._z = cosVal;
 		break;
@@ -145,6 +146,7 @@ void FPose::copyFrom(const FMatrix &src) {
 	_row3 = src._row3;
 }
 
+// This looks like DAffine DAffine::inverseTransform()
 FPose FPose::fn4() const {
 	float v2, v3, v6, v7, v8, v9, v10, v11;
 	float v12, v13, v14, v15, v16, v17, v18;
diff --git a/engines/titanic/star_control/fpose.h b/engines/titanic/star_control/fpose.h
index dbdd832067..02e00c914d 100644
--- a/engines/titanic/star_control/fpose.h
+++ b/engines/titanic/star_control/fpose.h
@@ -29,6 +29,7 @@ namespace Titanic {
 
 /*
  * This class combines a position and orientation in 3D space
+ * TODO: consider merging with DAffine
  */
 class FPose : public FMatrix {
 public:
@@ -59,6 +60,9 @@ public:
 	 */
 	void copyFrom(const FMatrix &src);
 
+        /**
+         * Probably the inverse of the this 3x4
+         */
 	FPose fn4() const;
 };
 
diff --git a/engines/titanic/star_control/star_camera.cpp b/engines/titanic/star_control/star_camera.cpp
index f1723856fc..9c1c598ede 100644
--- a/engines/titanic/star_control/star_camera.cpp
+++ b/engines/titanic/star_control/star_camera.cpp
@@ -230,14 +230,14 @@ void CStarCamera::setViewportAngle(const FPoint &angles) {
 	if (_matrixRow == -1) {
 		// No locked markers
 		FPose subX(X_AXIS, angles._y);
-		FPose subY(Y_AXIS, angles._x);
+		FPose subY(Y_AXIS, -angles._x); // needs to be negative or looking left will cause the view to go right
 		FPose sub(subX, subY);
 		proc22(sub);
 	} else if (_matrixRow == 0) {
 		// 1 marker is locked in
 		FVector row1 = _matrix._row1;
 		FPose poseX(X_AXIS, angles._y);
-		FPose poseY(Y_AXIS, angles._x);
+		FPose poseY(Y_AXIS, -angles._x); // needs to be negative or looking left will cause the view to go right
 		FPose pose(poseX, poseY);
 
 		FMatrix m1 = _viewport.getOrientation();