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TITANIC: daffine simpler inverse

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Replace rotation inverse with transpose.
inv(R)=tranpose(R) for rotation matrices.
This commit is contained in:
David Fioramonti 2017-08-16 18:31:36 -07:00
parent fb1e9453fb
commit 09eb399c07
1 changed files with 21 additions and 61 deletions
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82
engines/titanic/star_control/daffine.cpp
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@ -115,69 +115,29 @@ void DAffine::setRotationMatrix(Axis axis, double angleDeg) {
}
}
//TODO: Check math and provide source
//TODO: Check column 4 math
DAffine DAffine::inverseTransform() const {
double val1 = _col1._x * _col3._z * _col2._y;
double val2 = 0.0;
double val3 = val1;
if (val1 < 0.0) {
val2 = val3;
val1 = 0.0;
}
double val4 = _col3._x * _col1._y * _col2._z;
if (val4 < 0.0)
val2 = val2 + val4;
else
val1 = val1 + val4;
double val5 = _col3._y * _col1._z * _col2._x;
if (val5 < 0.0)
val2 = val2 + val5;
else
val1 = val1 + val5;
if (-(_col3._x * _col2._y * _col1._z) < 0.0)
val2 = val2 - _col3._x * _col2._y * _col1._z;
else
val1 = val1 - _col3._x * _col2._y * _col1._z;
if (-(_col1._y * _col3._z * _col2._x) < 0.0)
val2 = val2 - _col1._y * _col3._z * _col2._x;
else
val1 = val1 - _col1._y * _col3._z * _col2._x;
val3 = _col3._y * _col2._z;
double val6 = -(_col1._x * val3);
if (val6 < 0.0)
val2 = val2 + val6;
else
val1 = val1 + val6;
double val7 = val2 + val1;
assert(!(val7 == 0.0 || fabs(val7 / (val1 - val2)) < 1.0e-10));
double val8 = _col3._z * _col2._y;
double val9 = 1.0 / val7;
DAffine m;
m._col1._x = (val8 - val3) * val9;
m._col2._x = -((_col3._z * _col2._x - _col3._x * _col2._z) * val9);
m._col3._x = (_col3._y * _col2._x - _col3._x * _col2._y) * val9;
m._col1._y = -((_col1._y * _col3._z - _col3._y * _col1._z) * val9);
m._col2._y = (_col1._x * _col3._z - _col3._x * _col1._z) * val9;
m._col3._y = -((_col1._x * _col3._y - _col3._x * _col1._y) * val9);
m._col1._z = (_col1._y * _col2._z - _col2._y * _col1._z) * val9;
m._col2._z = -((_col1._x * _col2._z - _col1._z * _col2._x) * val9);
m._col3._z = (_col1._x * _col2._y - _col1._y * _col2._x) * val9;
m._col4._x = -(m._col1._x * _col4._x + _col4._y * m._col2._x
+ _col4._z * m._col3._x);
m._col4._y = -(_col4._z * m._col3._y + _col4._y * m._col2._y
+ _col4._x * m._col1._y);
m._col4._z = -(_col4._z * m._col3._z + _col4._x * m._col1._z
+ _col4._y * m._col2._z);
DAffine m;
//Inverse of rotation matrix is the transpose
m._col1._x = _col1._x;
m._col2._x = _col1._y;
m._col3._x = _col1._z;
m._col1._y = _col2._x;
m._col2._y = _col2._y;
m._col3._y = _col2._z;
m._col1._z = _col3._x;
m._col2._z = _col3._y;
m._col3._z = _col3._z;
m._col4._x = -(_col4._x * m._col1._x
+ _col4._y * m._col2._x
+ _col4._z * m._col3._x);
m._col4._y = -(_col4._x * m._col1._y
+ _col4._y * m._col2._y
+ _col4._z * m._col3._y);
m._col4._z = -(_col4._x * m._col1._z
+ _col4._y * m._col2._z
+ _col4._z * m._col3._z);
return m;
}