Fix segfault (lambda reference capture) of VisualizerWithCustomAnimation::Play

[nicolaloi]

Type

• Bug fix (non-breaking change which fixes an issue): Fixes Segmentation fault when play animation with o3d.visualization.draw_geometries_with_custom_animation #6589
• New feature (non-breaking change which adds functionality). Resolves #
• Breaking change (fix or feature that would cause existing functionality to not work as expected) Resolves #

Motivation and Context

Fixing segmentation fault when running an animation (clicking CTRL+P) with draw_geometries_with_custom_animation.

Checklist:

• I have run python util/check_style.py --apply to apply Open3D code style
  to my code.
• This PR changes Open3D behavior or adds new functionality.
  • Both C++ (Doxygen) and Python (Sphinx / Google style) documentation is
    updated accordingly.
  • I have added or updated C++ and / or Python unit tests OR included test
    results (e.g. screenshots or numbers) here.
• I will follow up and update the code if CI fails.
• For fork PRs, I have selected Allow edits from maintainers.

Description

The segmentation fault in VisualizerWithCustomAnimation.cpp is caused by line 124: ++progress_bar;, with progress_bar being a utility::ProgressBar instance captured by reference by a lambda expression. It seems like a dangling reference. Converting progress_bar to a shared pointer fixes the segmentation fault.

Testing

Before the change, this MRE will raise a segmentation fault after clicking CTRL+N and CTRL+P; after the change, it will run correctly:

# Instructions: When the window opens, 
# click CTRL+N to automatically add 360 spin keyframes, 
# then CTRL+P to play the animation

import open3d as o3d

with o3d.utility.VerbosityContextManager(o3d.utility.VerbosityLevel.Debug):
    sample_data = o3d.data.DemoCustomVisualization()
    pcd = o3d.io.read_point_cloud(sample_data.point_cloud_path)

    o3d.visualization.draw_geometries_with_custom_animation([pcd])

[ssheorey]

Thanks @nicolaloi looks good. I added a commit to fix the CI failure with clang.