upgrade to Filament 1.21.0

ios/include/math/quat.h

@@ -126,6 +126,44 @@ public:
     constexpr static TQuaternion MATH_PURE fromAxisAngle(const TVec3<A>& axis, B angle) {
         return TQuaternion(std::sin(angle * 0.5) * normalize(axis), std::cos(angle * 0.5));
     }
+
+    // constructs a quaternion from orig to dest.
+    // it returns the shortest arc and `from` and `to` must be normalized.
+    template<typename A, typename B, typename = enable_if_arithmetic_t<A, B>>
+    constexpr static TQuaternion MATH_PURE fromDirectedRotation(const TVec3<A>& from, const TVec3<B>& to) {
+        // see the implementation of glm/gtx/quaternion.hpp
+        T cosTheta = dot(from, to);
+        TVec3<T> rotationAxis;
+
+        if (cosTheta >= T(1) - std::numeric_limits<T>::epsilon()) {
+            // orig and dest point in the same direction
+            return TQuaternion(1, 0, 0, 0);
+        }
+
+        if (cosTheta < T(-1) + std::numeric_limits<T>::epsilon()) {
+            // special case when vectors in opposite directions :
+            // there is no "ideal" rotation axis
+            // So guess one; any will do as long as it's perpendicular to start
+            // This implementation favors a rotation around the Up axis (Y),
+            // since it's often what you want to do.
+            rotationAxis = cross(TVec3<T>(0, 0, 1), from);
+
+            if (length2(rotationAxis) < std::numeric_limits<T>::epsilon()) {
+                 // bad luck, they were parallel, try again!
+                 rotationAxis = cross(TVec3<T>(1, 0, 0), from);
+            }
+
+            rotationAxis = normalize(rotationAxis);
+            return fromAxisAngle(rotationAxis, F_PI);
+        }
+
+        // implementation from Stan Melax's Game Programming Gems 1 article
+        rotationAxis = cross(from, to);
+
+        const T s = std::sqrt((T(1) + cosTheta) * T(2));
+        return TQuaternion(s * T(0.5),
+                rotationAxis.x / s, rotationAxis.y / s, rotationAxis.z / s);
+    }
 };
 
 }  // namespace details