User defined type conversions from other vector classes are effectively disabled

[btmorex]

This constructor (and presumably corresponding constructors from different sized vectors):

    template <typename U> 
    GLM_FUNC_DECL explicit tvec2(
        U const & x);

prevents users from implementing type conversions from other vector classes which are very useful. C++ prefers constructors over conversion operators and U will match anything even if the U type cannot be converted to float or double.

So, even if I have the following:

struct my_vec {
operator glm::vec2() { return glm::vec2(x, y); }
float x, y;
};

It will not be used even with static_cast<glm::vec2>(my_vec())

I believe the desired behavior can be achieved with std::enable_if and std::is_convertible (at least for C++11 compilers)

[Groovounet]

This bug has been fixed in GLM 0.9.5.branch for GLM 0.9.5.1 release.
The change will generate warnings in case if required conversions but the feature seems relevant.

Thanks,
Christophe