I have this surface I plotted using Latex but the edge is ragged. Anyone knows how to fix that? I tried increasing the number of samples but the raggedness persists and the computing time becomes too much.

begin{tikzpicture}
    begin{axis}[
        view={67.5}{30}, 
        xmin=0, xmax=1, xtick={0,0.33,0.66,1},  xticklabels={0,$nicefrac{1}{3}$,$nicefrac{2}{3}$,1}, xlabel=$s_{1}$,
        ymin=0, ymax=1, ytick={0,0.33,0.66,1},  yticklabels={0,$nicefrac{1}{3}$,$nicefrac{2}{3}$,1}, ylabel=$s_{2}$,
        zmin=0.01, zmax=1.2, zlabel={$H(s_{i})$}, every axis z label/.style={at={(ticklabel cs:1.05)}, anchor=south}, minor z tick num=1,
        colormap/cool, colorbar, 
        domain=0:1,
        restrict z to domain=0:1.2,
        samples=50,  ]
    addplot3[surf, ]    {-x*ln(x) - y*ln(y) - (1-x-y)*ln(1-x-y)};
end{axis}
end{tikzpicture}}

Image here:

Again I tried increasing number of samples but didn’t really help