How to simplify my code with looping macros?

\documentclass[pstricks,preview,margin=5mm]{standalone}
\usepackage{multido}

\def\obj#1{%
    \begin{pspicture}(-2,-2)(2,2)
        \multido{\i=#1+30}{12}{\rput{\i}(0,0){\pswedge*(0,0){2}{0}{15}}}
    \end{pspicture}%
}

\begin{document}
\obj{0}\obj{15}%
\end{document}

Note: Starred \pswedge does not need linestyle=none,linewidth=0 to remove the outline because it has been done automatically.

\documentclass{article}

\usepackage{pstricks,multido}

\begin{document}

\begin{pspicture}
  \multido{\i=0+15}{24}{%
    \def\dowedge{\pswedge}%
    \ifodd\i\def\dowedge{\pswedge*}\fi
    \dowedge(0,0){2}{\i}{\number\numexpr\i+15}%
  }
\end{pspicture}

\end{document}

Potentially one could also draw a filled, black circle and insert 12 white wedges.

---

As a secondary request, you can set the linestyle to none, which removes the outer circle as well as the "inner dot". Effectively, there is then no need for printing the white wedges then, making to code a little lighter:

\documentclass{article}

\usepackage{pstricks,multido}

\begin{document}

\begin{pspicture}
  \multido{\i=0+30}{12}{%
    \pswedge*(0,0){2}{\i}{\number\numexpr\i+15}%
  }
\end{pspicture}

\end{document}

\foreach from pgffor package is also available by default in PSTricks. As a result, you don't need to use \multido.

\documentclass[pstricks,preview,margin=5mm]{standalone}

\begin{document}
\begin{pspicture}(-2,-2)(2,2)
\foreach \i [evaluate = \i as \j using \i+15] in {0,30,..., 330}{\pswedge*{2}{\i}{\j}}
\end{pspicture}
\end{document}

The output is exactly the same as other answers.