Govern task context and advance execution pointer

tools/web/check-particle-settings-desktop.py

@@ -0,0 +1,69 @@
+#!/usr/bin/env python3
+import hashlib
+import json
+import os
+import pathlib
+import sys
+import tempfile
+
+import bpy
+
+
+def rounded(value):
+    return round(float(value), 6)
+
+
+def settings_report():
+    settings = bpy.data.particles.get("WebGapParticleSettings")
+    if settings is None:
+        raise RuntimeError("WebGapParticleSettings is missing")
+    return {
+        "id": "particle-settings:" + settings.name,
+        "name": settings.name,
+        "type": int({"EMITTER": 0, "HAIR": 1}.get(settings.type, -1)),
+        "from": int({"FACE": 0, "VERT": 1, "VOLUME": 2}.get(settings.emit_from, -1)),
+        "distribution": int({"JIT": 0, "RAND": 1, "GRID": 2}.get(settings.distribution, -1)),
+        "physicsType": int({"NEWTON": 0, "KEYED": 1, "BOIDS": 2, "NO": 3}.get(settings.physics_type, -1)),
+        "totalParticles": int(settings.count),
+        "start": rounded(settings.frame_start),
+        "end": rounded(settings.frame_end),
+        "lifetime": rounded(settings.lifetime),
+        "size": rounded(settings.particle_size),
+        "drawSize": rounded(settings.display_size),
+    }
+
+
+def main():
+    arguments = sys.argv[sys.argv.index("--") + 1 :]
+    if len(arguments) != 2:
+        raise SystemExit("usage: blender -b --python check-particle-settings-desktop.py -- FIXTURE REPORT")
+    fixture, output = (pathlib.Path(value).resolve() for value in arguments)
+    bpy.ops.wm.open_mainfile(filepath=str(fixture), load_ui=False)
+    before = settings_report()
+    descriptor, temporary = tempfile.mkstemp(prefix="m16-particle-settings-reopen-", suffix=".blend", dir=fixture.parent)
+    os.close(descriptor)
+    try:
+        bpy.ops.wm.save_as_mainfile(filepath=temporary, check_existing=False, compress=True)
+        bpy.ops.wm.open_mainfile(filepath=temporary, load_ui=False)
+        after = settings_report()
+    finally:
+        pathlib.Path(temporary).unlink(missing_ok=True)
+    if before != after:
+        raise RuntimeError(f"particle settings save/reopen drift: {before} != {after}")
+    report = {
+        "schemaVersion": 1,
+        "task": "M16-GAP-00018",
+        "operation": "PARTICLE_SETTINGS_DATABLOCK_DESKTOP",
+        "fixture": str(fixture),
+        "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(),
+        "particleSettings": after,
+        "saveReopen": "EXACT",
+        "blenderVersion": bpy.app.version_string,
+    }
+    output.parent.mkdir(parents=True, exist_ok=True)
+    output.write_text(json.dumps(report, indent=2, sort_keys=True) + "\n", encoding="utf-8")
+    print(f"particle-settings-desktop-ok id={after['id']} count={after['totalParticles']} saveReopen=exact")
+
+
+if __name__ == "__main__":
+    main()