\documentclass{minimal}
\usepackage{pgfplots,tikz}
\begin{document}
\begin{tikzpicture}
\begin{axis}
\addplot[surf,shader=interp, mesh/rows=2]
table[row sep=crcr, point meta=\thisrow{c}] {%
x	y	c\\
0	1	0\\
0	2	1\\
1	1	1\\
1	2	0\\
};
\end{axis}
\end{tikzpicture}%
\end{document}