"# endif\n"
"# define dp_varying varying\n"
"# define dp_attribute attribute\n"
-"# define dp_offsetmapping_dFdx(a) 0\n"
-"# define dp_offsetmapping_dFdy(a) 0\n"
+"# define dp_offsetmapping_dFdx(a) vec2(0.0, 0.0)\n"
+"# define dp_offsetmapping_dFdy(a) vec2(0.0, 0.0)\n"
"# define dp_textureGrad(a,b,c,d) texture2D(a,b)\n"
"# define dp_texture2D texture2D\n"
"# define dp_texture3D texture3D\n"