PointClouds present in scene but not showing up

[DamienGilliard]

Describe the bug

I tried to visualize a point cloud in compas_viewer 2.0.1, but the point cloud did not show up, even though it is present in the list of object tab.

To Reproduce

Steps to reproduce the behavior:

using compas_viewer 2.0.1 and python 3.9, run the following script:

from compas.colors import Color
from compas.geometry import Pointcloud
from compas_viewer import Viewer

viewer = Viewer()
pointcloud = Pointcloud.from_bounds(10, 10, 10, 10)
viewer.scene.add(pointcloud, pointcolor=Color(1.0,0.0,0.0), pointsize=10)

viewer.show()

Expected behavior

you should get a scene with no point cloud but a point cloud in the geometry table:

If you bump down the version of compas_viewer to 1.3.2, it does show up:

Desktop (please complete the following information):

• OS: Fedora 43
• Python version: 3.9
• Python package manager: uv

I compared the versions 1.3.2 and 1.4.0 (when the visualisation was broken) and I saw that the model.frag in compas_viewer.renderer.shaders had a suspicious if statement:

    // Draw circular points
    if (element_type == 0) {
        vec2 center = gl_PointCoord - vec2(0.5);
        if (length(center) > 0.5) {
            discard;
        }

sure enough, when simply deleting it, the point cloud did show up (with square points...) :

Next step

I started using compas_viewer yesterday so I am not familiar with how it works yet (especially the opengl & qt side of things) so maybe I won't make a PR immediately to fix this, unless you tell me the exact nail to hit, then I'll gladly do it ;)

[DamienGilliard]

good/bad news:

• good news: the issue is not present on windows:
  

• bad news: the issue is thus related to open-gl on linux... (I assume)

[DamienGilliard]

OK I have found a workaround. I'll make a PR and you tell me what you think of it... I basically add a flag use_circular_points in the Shader class that checks is the sys.platform is "linux", that is then used in the model.frag to apply the circular mask or not. Not very elegant but "it works"