83 lines
2.9 KiB
Markdown
83 lines
2.9 KiB
Markdown
# Blender Asset Tracer BAT🦇
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Script to manage assets with Blender.
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Blender Asset Tracer, a.k.a. BAT🦇, is the replacement of
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[BAM](https://developer.blender.org/diffusion/BAM/) and
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[blender-file](https://developer.blender.org/source/blender-file/)
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Development is driven by choices explained in [T54125](https://developer.blender.org/T54125).
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## Uploading to S3-compatible storage
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BAT Pack supports uploading to S3-compatible storage. This requires a credentials file in
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`~/.aws/credentials`. Replace the all-capital words to suit your situation.
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[ENDPOINT]
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aws_access_key_id = YOUR_ACCESS_KEY_ID
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aws_secret_access_key = YOUR_SECRET
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You can then send a BAT Pack to the storage using a target `s3:/ENDPOINT/bucketname/path-in-bucket`,
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for example:
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bat pack my_blendfile.blend s3:/storage.service.cloud/jobs/awesome_work
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This will upload the blend file and its dependencies to `awesome_work/my_blendfile.blend` in
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the `jobs` bucket.
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## Paths
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There are two object types used to represent file paths. Those are strictly separated.
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1. `bpathlib.BlendPath` represents a path as stored in a blend file. It consists of bytes, and is
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blendfile-relative when it starts with `//`. It can represent any path from any OS Blender
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supports, and as such should be used carefully.
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2. `pathlib.Path` represents an actual path, possibly on the local filesystem of the computer
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running BAT. Any filesystem operation (such as checking whether it exists) must be done using a
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`pathlib.Path`.
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When it is necessary to interpret a `bpathlib.BlendPath` as a real path instead of a sequence of
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bytes, BAT first attempts to decode it as UTF-8. If that fails, the local filesystem encoding is
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used. The latter is also no guarantee of correctness, though.
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## Type checking
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The code statically type-checked with [mypy](http://mypy-lang.org/).
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Mypy likes to see the return type of `__init__` methods explicitly declared as `None`. Until issue
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[#604](https://github.com/python/mypy/issues/604) is resolved, we just do this in our code too.
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## Code Example
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BAT can be used as a Python library to inspect the contents of blend files, without having to
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open Blender itself. Here is an example showing how to determine the render engine used:
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#!/usr/bin/env python3.7
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import sys
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from pathlib import Path
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from blender_asset_tracer import blendfile
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from blender_asset_tracer.blendfile import iterators
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if len(sys.argv) != 2:
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print(f'Usage: {sys.argv[0]} somefile.blend', file=sys.stderr)
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sys.exit(1)
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bf_path = Path(sys.argv[1])
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bf = blendfile.open_cached(bf_path)
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window_managers = bf.find_blocks_from_code(b'WM')
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assert window_managers, 'The Blend file has no window manager'
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window_manager = window_managers[0]
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windows = window_manager.get_pointer((b'windows', b'first'))
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for window in iterators.listbase(windows):
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scene = window.get_pointer(b'scene')
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break
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print(scene[b'r', b'engine'].decode('utf8'))
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