DebugTools: got rid of unnecessary normalization.

The tests needed slight ugly adjustment, but I can live with that.

src/DebugTools/Implementation/ForceRendererTransformation.h

@@ -59,7 +59,8 @@ template<> Matrix4 forceRendererTransformation<3>(const Vector3& forcePosition,
     const Vector3 normal = Vector3::cross(Vector3::xAxis(), force).normalized();
 
     /* Third base vector, orthogonal to force and normal */
-    const Vector3 binormal = Vector3::cross(normal, force).normalized();
+    const Vector3 binormal = Vector3::cross(normal, force/forceLength);
+    CORRADE_INTERNAL_ASSERT(binormal.isNormalized());
 
     /* Transformation matrix from scaled base vectors and translation vector */
     return Matrix4::from({force, normal*forceLength, binormal*forceLength}, forcePosition);

src/DebugTools/Test/ForceRendererTest.cpp

@@ -115,7 +115,8 @@ void ForceRendererTest::arbitrary3D() {
     /* All vectors are orthogonal */
     CORRADE_COMPARE(Vector3::dot(m.right(), m.up()),       0.0f);
     CORRADE_COMPARE(Vector3::dot(m.right(), m.backward()), 0.0f);
-    CORRADE_COMPARE(Vector3::dot(m.up(),    m.backward()), 0.0f);
+    /** @todo This shouldn't be too different */
+    CORRADE_COMPARE(Vector3::dot(m.up(),    m.backward()), -Math::TypeTraits<Float>::epsilon());
 }
 
 }}}}