Thread: Template problem

I had the following class:

Code:

/*!
 * \brief Provides text drawing-methods for OpenGL.
 */
class ZTextDrawer2
{
    public:
    /*
        various stuff
        ..........
        ..........
    */
       
    void Draw2DText(DrawPoint<float> p, const char *format, ...);
    void Draw3DText(DrawPoint<float> p, const char *format, ...);

    private:
    /*
        various stuff
        ..........
        ..........
    */
}

I had not problems with it, and it worked as it should be. Problems rised when I
decided it t change it to the following:

Code:

/*!
 * \brief Provides text drawing-methods for OpenGL.
 */
class ZTextDrawer2
{
    public:
    /*
        various stuff
        ..........
        ..........
    */
       
    template<typename Scalar> void Draw2DText(DrawPoint<Scalar> p, const char *format, ...);
    template<typename Scalar> void Draw3DText(DrawPoint<Scalar> p, const char *format, ...);

    private:
    /*
        various stuff
        ..........
        ..........
    */
}

In both cases the class is used like that:

Code:

ZTextDrawer2::GetInstance()->Draw2DText(DrawPoint<float> (0.0f, 0.0f), "ZTextDrawer2");

The problem with the second version of the class is that I get link errors(i use GCC):

Code:

obj\test.o:test.cpp|| undefined reference to `void Z_GLC::ZTextDrawer2::Draw2DText<float>(Z_GLC::DrawPoint<float>, char const*, ...|

Why is this link error caused?

EDIT:

The DrawPoint struct is defined as following:

Code:

template<class T> struct DrawPoint
{
    T x, y;

    DrawPoint() : x(0), y(0) {}
    DrawPoint(T _x, T _y) : x(_x), y(_y) {}
};