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Fix Euler rotation matrix convention in Matrix3f and Matrix4f - #41
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Matrix3f.setEulers had m[1][1] and m[2][1] swapped compared to the standard R=Rh(Y)*Rp(X)*Rr(Z) rotation matrix that both Quaternion and the Vince reference use. Matrix3f.getEulers correspondingly extracted cosr from the wrong element. Matrix4f.setEulers used a different convention (heading about Z, pitch about Y, roll about X) instead of the Y-X-Z convention used by Quaternion. Aligned it to match. Closes #34
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Summary
Root cause
Matrix3f.setEulers had two matrix elements transposed, producing the wrong rotation matrix. Matrix4f.setEulers used a different rotation order entirely (heading about Z) versus the Y-X-Z convention used by Quaternion.setEulers (Vince p.201) and Quaternion.getMat3 (Vince p.202). The convention mismatch caused 3x-magnitude errors in Euler round-trips.
Verified numerically against R = Rh(Y) * Rp(X) * Rr(Z) computed from first principles.
Closes #34
Test plan
QuaternionTest.testEulersRoundTrip()passesQuaternionTest.testMatrix3fRoundTrip()passesQuaternionTest.testMatrix4fRoundTrip()passes