nerdcruft/libcruft-util
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quaternion: add naive from_to implementation

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This commit is contained in:
Danny Robson 2016-10-17 18:58:11 +11:00
parent 1582af98e6
commit df27f5f89e
1 changed files with 8 additions and 0 deletions
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8
quaternion.cpp
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@ -76,6 +76,13 @@ quaternion<S,T>::from_to (const vector<3,T> u, const vector<3,T> v)
CHECK (is_normalised (u)); CHECK (is_normalised (u));
CHECK (is_normalised (v)); CHECK (is_normalised (v));
#if 0
// Naive:
auto cos_theta = dot (u, v);
auto angle = std::acos (cos_theta);
auto axis = normalised (cross (u, v));
return angle_axis (angle, axis);
#elif 1
auto norm_u_norm_v = std::sqrt(dot(u, u) * dot(v, v)); auto norm_u_norm_v = std::sqrt(dot(u, u) * dot(v, v));
auto real_part = norm_u_norm_v + dot(u, v); auto real_part = norm_u_norm_v + dot(u, v);
util::vector<3,T> w; util::vector<3,T> w;
@ -97,6 +104,7 @@ quaternion<S,T>::from_to (const vector<3,T> u, const vector<3,T> v)
} }
return normalised (util::quaternion<4,T> (real_part, w.x, w.y, w.z)); return normalised (util::quaternion<4,T> (real_part, w.x, w.y, w.z));
#endif
} }