Simplified Code without unnecessary %

\documentclass
[
  pstricks,
  border=12pt,
]{standalone}

\usepackage{pst-3dplot}

\begin{document}

\begin{pspicture}(-3,-3)(3,4)
\pstThreeDCoor
[
  xMin=-4,
  xMax=4,
  yMin=-4,
  yMax=4,
  zMax=3,
  arrows=<->,
]
\psplotThreeD
[
  plotstyle=line,
  linecolor=blue,
  yPlotpoints=40,
  xPlotpoints=30,
  linewidth=0.5pt,
  hiddenLine=true,
](-2,2)(-2,2)
{
  x 100 mul cos y 100 mul sin sub
}
\rput[tl](-2,3.5){$f(x,y) = \cos(100x) - \sin(100y)$}
\end{pspicture}

\end{document}