Make sure faces are integers before writing surface geometries

[dipterix]

The goal is to fix this issue when writing double as integer32:

mesh <- rgl::icosahedron3d(diag(c(50, 50, 50, 1)))
f <- tempfile()

faces <- t(mesh$it)
faces
#>       [,1] [,2] [,3]
#>  [1,]    1    3    9
#>  [2,]    1    9    5
#>  [3,]    1    5    7
#>  [4,]    1    7   10
#>  [5,]    1   10    3
#>  [6,]    4   12    2
#>  [7,]    4    2   11
#>  [8,]    4   11    6
#>  [9,]    4    6    8
#> [10,]    4    8   12
#> [11,]    9    3    6
#> [12,]    5    9   11
#> [13,]    7    5    2
#> [14,]   10    7   12
#> [15,]    3   10    8
#> [16,]    2   12    7
#> [17,]   11    2    5
#> [18,]    6   11    9
#> [19,]    8    6    3
#> [20,]   12    8   10
# storage.mode(faces) <- "integer"
freesurferformats::write.fs.surface.gii(
  filepath = f,
  vertex_coords = t(mesh$vb[1:3, ]),
  faces = faces
)

m <- freesurferformats::read.fs.surface.gii(f)

m$faces
#>             [,1]       [,2]       [,3]
#>  [1,]          1 1073741825 1090519041
#>  [2,]          1 1090519041 1082130433
#>  [3,]          1 1082130433 1086324737
#>  [4,]          1 1086324737 1091567617
#>  [5,]          1 1091567617 1073741825
#>  [6,] 1077936129 1093664769 1065353217
#>  [7,] 1077936129 1065353217 1092616193
#>  [8,] 1077936129 1092616193 1084227585
#>  [9,] 1077936129 1084227585 1088421889
#> [10,] 1077936129 1088421889 1093664769
#> [11,] 1090519041 1073741825 1084227585
#> [12,] 1082130433 1090519041 1092616193
#> [13,] 1086324737 1082130433 1065353217
#> [14,] 1091567617 1086324737 1093664769
#> [15,] 1073741825 1091567617 1088421889
#> [16,] 1065353217 1093664769 1086324737
#> [17,] 1092616193 1065353217 1082130433
#> [18,] 1084227585 1092616193 1090519041
#> [19,] 1088421889 1084227585 1073741825
#> [20,] 1093664769 1088421889 1091567617

[dfsp-spirit]

Thanks for the fix, much appreciated.