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Fixed quaternion constructor from two vectors special cases #469

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This commit is contained in:
Christophe Riccio
2017-08-22 22:47:36 +02:00
parent 4e0c87683c
commit 6932058f59
3 changed files with 36 additions and 9 deletions
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22
glm/gtc/quaternion.inl
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@@ -148,11 +148,25 @@ namespace detail
template<typename T, qualifier Q>
GLM_FUNC_QUALIFIER tquat<T, Q>::tquat(vec<3, T, Q> const& u, vec<3, T, Q> const& v)
{
vec<3, T, Q> const LocalW(cross(u, v));
T Dot = detail::compute_dot<vec<3, T, Q>, T, detail::is_aligned<Q>::value>::call(u, v);
tquat<T, Q> q(T(1) + Dot, LocalW.x, LocalW.y, LocalW.z);
T norm_u_norm_v = sqrt(dot(u, u) * dot(v, v));
T real_part = norm_u_norm_v + dot(u, v);
vec<3, T, Q> w;
*this = normalize(q);
if(real_part < static_cast<T>(1.e-6f) * norm_u_norm_v)
{
// If u and v are exactly opposite, rotate 180 degrees
// around an arbitrary orthogonal axis. Axis normalisation
// can happen later, when we normalise the quaternion.
real_part = static_cast<T>(0);
w = abs(u.x) > abs(u.z) ? vec<3, T, Q>(-u.y, u.x, static_cast<T>(0)) : vec<3, T, Q>(static_cast<T>(0), -u.z, u.y);
}
else
{
// Otherwise, build quaternion the standard way.
w = cross(u, v);
}
*this = normalize(tquat<T, Q>(real_part, w.x, w.y, w.z));
}
template<typename T, qualifier Q>