Python viewer

[JuanTheEngineer]

Motivation and Context

• Clean up Python Viewer
• Enrich the viewer application with some additional features and utilities. For example, features of interest may include:
  • moving the camera with keyboard and mouse
  • reloading the scene
  • run and pause simulations
  • load ReplicaCAD data sets

All features can be seen in help text.

Previous PRs: 727 & 1056

How Has This Been Tested

In order to run the viewer, you must use the commands below.

1. Build Habitat-Sim

# build habitat with bullet physics
python setup.py install --bullet
# or
./build.sh --bullet

# Add habitat-sim to PYTHONPATH
export PYTHONPATH=$(pwd)

2. Run Habitat-Sim

# Example structure
python examples/viewer.py --scene [SCENE] --dataset [DATASET]

# Example with ReplicaCAD
python examples/viewer.py --dataset /path/to/data/versioned_data/replica_cad_dataset_1.1/replicaCAD.scene_dataset_config.json --scene apt_0

3. Commands

# For args help
python examples/viewer.py -h

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes.
• All new and existing tests passed.

[dhruvbatra]

Very cool. I was able to test and reproduce on a mac with building from source.

However, it only works with ./build.sh --bullet. If I build using python setup.py install --bullet, I see the following error (which is likely not related to your PR):

Traceback (most recent call last):
  File "examples/viewer.py", line 1, in <module>
    from magnum import gl
  File "/Users/dbatra/miniconda3/envs/habitat-src/lib/python3.6/site-packages/magnum/__init__.py", line 28, in <module>
    from _magnum import *
ImportError: dlopen(/Users/dbatra/miniconda3/envs/habitat-src/lib/python3.6/site-packages/_magnum.cpython-36m-darwin.so, 2): Library not loaded: @rpath/libMagnum.2.dylib
  Referenced from: /Users/dbatra/miniconda3/envs/habitat-src/lib/python3.6/site-packages/_magnum.cpython-36m-darwin.so
  Reason: image not found

[Skylion007]

@JuanTheEngineer Pulling from master should resolve the CI CA issues.

[Skylion007]

@JuanTheEngineer You also need to run pre-commit on this PR for proper formatting + linting. pre-commit run -a

[aclegg3]

Very cool. I was able to test and reproduce on a mac with building from source.

However, it only works with ./build.sh --bullet. If I build using python setup.py install --bullet, I see the following error (which is likely not related to your PR):

Yes, this is related to the issue @Skylion007 mentioned. For now ./build.sh --bullet with dynamic linking is the workaround.

@JuanTheEngineer thanks for the thorough instructions in the testing section. Maybe add a line that building with setup.py isn't working for now also.

[mosra]

Once #1529 is merged, these two changes should allow you to resize the window. However, viewer.cpp's viewportEvent() has a lot of code to resize all existing framebuffers and I'm not sure how/if these are exposed to Python. So it's possibly not even implementable at this point.

[Skylion007]

Instead rebasing, you may just want to pull from main next time as it would also make reviewing this PR a bit easier.

[aclegg3]

Looks good, almost ready. A couple of notes from our chat.

[aclegg3]

Love this reduction. 👍

[aclegg3]

Looks good. Let's merge it. 🥳

addressed