Added support for 3d surface meshes

src/backends/gr.jl

@@ -1947,6 +1947,9 @@ function gr_draw_surface(series, x, y, z, clims)
     e_kwargs = series[:extra_kwargs]
     st = series[:seriestype]
     if st === :surface
+        if ndims(x) == ndims(y) == ndims(z) == 2
+            GR.gr3.surface(x', y', z, GR.OPTION_3D_MESH)
+        else
             fillalpha = get_fillalpha(series)
             fillcolor = get_fillcolor(series)
             # NOTE: setting nx = 0 or ny = 0 disables GR.gridit interpolation
@@ -1961,6 +1964,7 @@ function gr_draw_surface(series, x, y, z, clims)
             else
                 GR.gr3.surface(x, y, z, d_opt)
             end
+        end
     elseif st === :wireframe
         GR.setfillcolorind(0)
         GR.surface(x, y, z, get(e_kwargs, :display_option, GR.OPTION_FILLED_MESH))