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More stable Matrix->Quat constructor

This commit is contained in:
Jack Andersen 2016-04-08 14:00:48 -10:00
parent 5aae3cdbc6
commit eb2968304b
1 changed files with 36 additions and 5 deletions
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41
include/zeus/CQuaternion.hpp
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@ -44,11 +44,42 @@ public:
CQuaternion(const CMatrix3f& mat)
{
w = std::sqrt(1.0f + mat[0][0] + mat[1][1] + mat[2][2]) / 2.0f;
double w4 = 4.0f * w;
x = (mat[1][2] - mat[2][1]) / w4;
y = (mat[2][0] - mat[0][2]) / w4;
z = (mat[0][1] - mat[1][0]) / w4;
float trace = mat[0][0] + mat[1][1] + mat[2][2];
if (trace > 0)
{
float s = 0.5f / std::sqrt(trace + 1.0f);
w = 0.25f / s;
x = (mat[1][2] - mat[2][1]) * s;
y = (mat[2][0] - mat[0][2]) * s;
z = (mat[0][1] - mat[1][0]) * s;
}
else
{
if (mat[0][0] > mat[1][1] && mat[0][0] > mat[2][2])
{
float s = 2.0f * std::sqrt(1.0f + mat[0][0] - mat[1][1] - mat[2][2]);
w = (mat[1][2] - mat[2][1]) / s;
x = 0.25f * s;
y = (mat[1][0] + mat[0][1]) / s;
z = (mat[2][0] + mat[0][2]) / s;
}
else if (mat[1][1] > mat[2][2])
{
float s = 2.0f * std::sqrt(1.0f + mat[1][1] - mat[0][0] - mat[2][2]);
w = (mat[2][0] - mat[0][2]) / s;
x = (mat[1][0] + mat[0][1]) / s;
y = 0.25f * s;
z = (mat[2][1] + mat[1][2]) / s;
}
else
{
float s = 2.0f * std::sqrt(1.0f + mat[2][2] - mat[0][0] - mat[1][1]);
w = (mat[0][1] - mat[1][0]) / s;
x = (mat[2][0] + mat[0][2]) / s;
y = (mat[2][1] + mat[1][2]) / s;
z = 0.25f * s;
}
}
}
operator atVec4f()