From 24354ac6a8425133e3b39caa1e55b4b63dc41665 Mon Sep 17 00:00:00 2001
From: David Fioramonti
Date: Wed, 16 Aug 2017 19:44:11 -0700
Subject: TITANIC: fpose, simplify inverse

Was doing 3x3 inverse now it is doing a transpose.
Also named the function.
---
 engines/titanic/star_control/fpose.cpp    | 81 ++++++++-----------------------
 engines/titanic/star_control/fpose.h      |  6 +--
 engines/titanic/star_control/viewport.cpp |  2 +-
 3 files changed, 24 insertions(+), 65 deletions(-)

(limited to 'engines/titanic')

diff --git a/engines/titanic/star_control/fpose.cpp b/engines/titanic/star_control/fpose.cpp
index 98de447e85..a3697ae6d5 100644
--- a/engines/titanic/star_control/fpose.cpp
+++ b/engines/titanic/star_control/fpose.cpp
@@ -146,69 +146,28 @@ 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;
+FPose FPose::inverseTransform() const {
 	FPose result;
 
-	v16 = _row3._z * _row2._y;
-	v2 = _row1._x * v16;
-	v3 = 0.0;
-	v18 = v2;
-	if (v2 < 0.0) {
-		v3 = v18;
-		v2 = 0.0;
-	}
-	v6 = _row3._x * _row1._y * _row2._z;
-	if (v6 < 0.0)
-		v3 = v3 + v6;
-	else
-		v2 = v2 + v6;
-	v7 = _row3._y * _row1._z * _row2._x;
-	if (v7 < 0.0)
-		v3 = v3 + v7;
-	else
-		v2 = v2 + v7;
-	if (-(_row3._x * _row1._z * _row2._y) < 0.0)
-		v3 = v3 - _row3._x * _row1._z * _row2._y;
-	else
-		v2 = v2 - _row3._x * _row1._z * _row2._y;
-	if (-(_row1._y * _row2._x * _row3._z) < 0.0)
-		v3 = v3 - _row1._y * _row2._x * _row3._z;
-	else
-		v2 = v2 - _row1._y * _row2._x * _row3._z;
-	v17 = _row2._z * _row3._y;
-	if (-(_row1._x * v17) < 0.0)
-		v3 = v3 - _row1._x * v17;
-	else
-		v2 = v2 - _row1._x * v17;
-	v18 = v3 + v2;
-	assert(!(v18 == 0.0 || fabs(v18 / (v2 - v3)) < 1.0e-10));
-
-	v8 = 1.0 / v18;
-	v18 = v8;
-	result._row1._x = (v16 - v17) * v8;
-	result._row2._x = -(_row2._x * _row3._z - _row3._x * _row2._z) * v8;
-	result._row3._x = (_row3._y * _row2._x - _row3._x * _row2._y) * v8;
-	result._row1._y = -(_row1._y * _row3._z - _row3._y * _row1._z) * v8;
-	result._row2._y = (_row1._x * _row3._z - _row3._x * _row1._z) * v8;
-	result._row3._y = -(_row1._x * _row3._y - _row3._x * _row1._y) * v8;
-	result._row1._z = (_row1._y * _row2._z - _row1._z * _row2._y) * v8;
-	result._row2._z = -(_row1._x * _row2._z - _row1._z * _row2._x) * v8;
-	v9 = result._row1._x;
-	v10 = result._row2._y;
-	v11 = result._row3._y;
-	v12 = result._row1._z;
-	v13 = result._row2._z;
-	result._row3._z = (_row1._x * _row2._y - _row1._y * _row2._x) * v18;
-	v14 = v9;
-	v15 = result._row3._z;
-	result._vector._x = -(v14 * _vector._x
-		+ _vector._y * result._row2._x
-		+ _vector._z * result._row3._x);
-	result._vector._y = -(_vector._x * result._row1._y + v10 * _vector._y + v11 * _vector._z);
-	result._vector._z = -(v12 * _vector._x + v13 * _vector._y + v15 * _vector._z);
+	result._row1._x = _row1._x;
+	result._row2._x = _row1._y;
+	result._row3._x = _row1._z;
+	result._row1._y = _row2._x;
+	result._row2._y = _row2._y;
+	result._row3._y = _row2._z;
+	result._row1._z = _row3._x;
+	result._row2._z = _row3._y;
+	result._row3._z = _row3._z;
+
+	result._vector._x = -(_vector._x * result._row1._x
+		            + _vector._y * result._row2._x
+		            + _vector._z * result._row3._x);
+	result._vector._y = -(_vector._x * result._row1._y
+                           + _vector._y * result._row2._y
+                           + _vector._z * result._row3._y);
+	result._vector._z = -(_vector._x * result._row1._z
+                           + _vector._y * result._row2._z
+                           + _vector._z * result._row3._z);
 
 	return result;
 }
diff --git a/engines/titanic/star_control/fpose.h b/engines/titanic/star_control/fpose.h
index 02e00c914d..f1f00ea7a7 100644
--- a/engines/titanic/star_control/fpose.h
+++ b/engines/titanic/star_control/fpose.h
@@ -29,7 +29,7 @@ namespace Titanic {
 
 /*
  * This class combines a position and orientation in 3D space
- * TODO: consider merging with DAffine
+ * TODO: Merge with DAffine
  */
 class FPose : public FMatrix {
 public:
@@ -61,9 +61,9 @@ public:
 	void copyFrom(const FMatrix &src);
 
         /**
-         * Probably the inverse of the this 3x4
+         * The inverse of rotation and the position vector
          */
-	FPose fn4() const;
+	FPose inverseTransform() const;
 };
 
 } // End of namespace Titanic
diff --git a/engines/titanic/star_control/viewport.cpp b/engines/titanic/star_control/viewport.cpp
index 39d2c5f201..130d59d8d6 100644
--- a/engines/titanic/star_control/viewport.cpp
+++ b/engines/titanic/star_control/viewport.cpp
@@ -248,7 +248,7 @@ void CViewport::reset() {
 
 	_rawPose.copyFrom(_orientation);
 	_rawPose._vector = _position;
-	_currentPose = _rawPose.fn4();
+	_currentPose = _rawPose.inverseTransform();
 
 	_center = FPoint((double)_width * 0.5, (double)_height * 0.5);
 	_centerVector._x = MIN(_center._x, _center._y);
-- 
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