Drawing normals as lines crashes CC on macOS

[tonttu]

When trying to visualize point cloud normals, CloudCompare shows an error message and quits:

ERROR: 0:8: ';' : syntax error: Uniform blocks may not have identifiers in GLSL 140

How to reproduce

1. Drag and drop the attached cube.ply onto Cloud Compare window and click Apply
2. Click on the "cube - Cloud" item in the DB Tree
3. Click on "Draw" checkbox from Properties -> Draw normals as lines

Expected behaviour
I would expect the normals to be visualized, or if the system doesn't support the necessary GLSL features, at least CC could just inform the user, disable the checkbox and continue working without exiting.

Your environment

• CC Version: 2.13.1 with Qt 5.15.8
• OS & Version: macOS 13.6 on Apple M2 Pro

Test file (save as cube.ply, GitHub complains "We don't support that file type" when trying to attach this, so copy-pasting the file inline):

ply
format ascii 1.0
element vertex 8
property float x
property float y
property float z
property float nx
property float ny
property float nz
end_header
1.000000 1.000000 1.000000 0.577350 0.577350 0.577350
-1.000000 1.000000 1.000000 -0.577350 0.577350 0.577350
-1.000000 -1.000000 1.000000 -0.577350 -0.577350 0.577350
1.000000 -1.000000 1.000000 0.577350 -0.577350 0.577350
1.000000 -1.000000 -1.000000 0.577350 -0.577350 -0.577350
-1.000000 -1.000000 -1.000000 -0.577350 -0.577350 -0.577350
-1.000000 1.000000 -1.000000 -0.577350 0.577350 -0.577350
1.000000 1.000000 -1.000000 0.577350 0.577350 -0.577350

[rjanvier]

Hi, it's confirmed. We know this shader is problematic in some aspects. We will rework it. I'll take a look, most probably in the end of next week.

[tonttu]

@rjanvier That would be great, thanks. If you are touching the code anyway, perhaps also adjust the minimum normal length. Now the UI doesn't allow entering numbers smaller than 0.01, which is kind of frustrating when working with models that themselves are roughly that size.