Initializes a #graphene_euler_t using the angles contained in a #graphene_vec3_t.
If the #graphene_vec3_t v is null, the #graphene_euler_t will be initialized with all angles set to 0.
a #graphene_vec3_t containing the rotation angles in degrees
the order used to apply the rotations
the initialized #graphene_euler_t
Initializes a #graphene_euler_t using the angles contained in a #graphene_vec3_t.
If the #graphene_vec3_t v is null, the #graphene_euler_t will be initialized with all angles set to 0.