sample points on the floor in a particular region

[aclegg3]

Motivation and Context

This PR adds a simulation utility function to sample points on the floor in a particular SemanticRegion using navmesh sampling.

High level algorithm:

• first snap the region AABB center to the navmesh and attempt sampling within 1 meter of that point. This will work nicely for many convex regions.
• if nearby center sampling fails, globally sample the entire navmesh (or island)
• in both cases above, search for the sample with the greatest "distance_to_obstacle" (a heuristic for open space around the point) in order to find "good" points with maximum accessibility.

An option exists to limit sampling to a maximum number of attempts and to return the first valid sample if time is more important than the other qualities mentioned above.

How Has This Been Tested

TODO: need a CI test, but no region annotations in testing assets yet so deferring to a later PR.

Tested locally with a viewer application:

point_in_region-2024-05-08_16.02.34.mp4

In the video, yellow circles are sampled as the agent enters a new region.

Types of changes

• [Development] A pull request that add new features to the habitat-lab task and environment codebase. Development Pull Requests must be small (less that 500 lines of code change), have unit testing, very extensive documentation and examples. These are typically new tasks, environments, sensors, etc... The review process for these Pull Request is longer because these changes will be maintained by our core team of developers, so make sure your changes are easy to understand!

Checklist

• My code follows the code style of this project.
• I have updated the documentation if required.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes if required.

[xavierpuigf]

Looks great to me! Thanks Alex!!

[zephirefaith]

Tested in hab-llm a bit and worked as expected! Thank you for this superquick fix!

[0mdc]

LGTM!