Writing to GIfTI with face index stored as float results in errors

[dipterix]

Hi @dfsp-spirit , I recently encountered an issue when saving geometry when faces storage is not integer. Here's an reproducible example:

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

faces <- t(mesh$it)
faces[1:4, ]
#>       [,1] [,2] [,3]
#>  [1,]    1    3    9
#>  [2,]    1    9    5
#>  [3,]    1    5    7
#>  [4,]    1    7   10

# storage.mode(faces) <- "double"
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[1:4, ]
#>             [,1]       [,2]       [,3]
#>  [1,]          1 1073741825 1090519041
#>  [2,]          1 1090519041 1082130433
#>  [3,]          1 1082130433 1086324737
#>  [4,]          1 1086324737 1091567617

The issue was caused due to writing faces as float and then read back as integer32. A PR has been opened last night for this. #32.

Please let me know if anything is needed.

[dfsp-spirit]

Thanks, I'll have a look and let you know.

[dfsp-spirit]

I merged the PR, this will be part of the next release.