4 (declare (in) float p))
5 ((return (expression float dFdx (var_ref p)))))
10 ((return (expression vec2 dFdx (var_ref p)))))
14 (declare (in) vec3 p))
15 ((return (expression vec3 dFdx (var_ref p)))))
19 (declare (in) vec4 p))
20 ((return (expression vec4 dFdx (var_ref p)))))