sendUniform

    /// send Uniform
    void sendUniform(T)(int position, T t) {
        assert(this.isAttached, "cannot send uniform, shader not attached");
        static if(isFloatingPoint!T) {
            glUniform1f(position, t);
        }
        else static if(isIntegral!T) {
            glUniform1i(position, t);
        }
        else static if(isVector!T && isFloatingPoint!(T.vt)) {
            mixin("glUniform"~to!string(T.dimension)~"fv(position, 1, t.value_ptr);");
        }
        else static if(isVector!T && isIntegral!(T.vt)) {
            mixin("glUniform"~to!string(T.dimension)~"iv(position, 1, t.value_ptr);");
        }
        else static if(isMatrix!T && isNumeric!(T.mt) && T.cols >= 2 && T.cols <= 4 && T.rows >= 2 && T.rows <= 4) {
            static if(isFloatingPoint!(T.mt)) {
                static if(T.cols != T.rows)
                    mixin("glUniformMatrix"~to!string(T.cols)~"x"~to!string(T.rows)~"fv(position, 1, false, t.value_ptr);");
                else
                    mixin("glUniformMatrix"~to!string(T.cols)~"fv(position, 1, false, t.value_ptr);");
            }
            else static if(isIntegral!(T.mt)) {
                static if(T.cols != T.rows)
                    mixin("glUniformMatrix"~to!string(T.cols)~"x"~to!string(T.rows)~"fi(position, 1, false, t.value_ptr);");
                else
                    mixin("glUniformMatrix"~to!string(T.cols)~"fi(position, 1, false, t.value_ptr);");
            }
        }
        else
        {
            static assert(false, "Type "~T.stringof~" can not be sent via sendUniform");
        }
        glCheck();
    }