Govern task context and advance execution pointer

tools/web/check-mesh-desktop.py

@@ -0,0 +1,73 @@
+#!/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 mesh_report():
+    mesh = bpy.data.meshes.get("WebGapMesh")
+    if mesh is None:
+        raise RuntimeError("WebGapMesh is missing")
+    mesh.calc_loop_triangles()
+    positions = [rounded(value) for vertex in mesh.vertices for value in vertex.co]
+    indices = [index for triangle in mesh.loop_triangles for index in triangle.vertices]
+    uv_layer = mesh.uv_layers.get("WebGapUV")
+    uvs = [rounded(value) for loop in uv_layer.data for value in loop.uv] if uv_layer else []
+    return {
+        "id": "mesh:WebGapMesh",
+        "name": mesh.name,
+        "vertexCount": len(mesh.vertices),
+        "edgeCount": len(mesh.edges),
+        "faceCount": len(mesh.polygons),
+        "cornerCount": len(mesh.loops),
+        "triangleCount": len(mesh.loop_triangles),
+        "positions": positions,
+        "indices": indices,
+        "uvLayers": [layer.name for layer in mesh.uv_layers],
+        "uvs": uvs,
+    }
+
+
+def main() -> None:
+    arguments = sys.argv[sys.argv.index("--") + 1 :]
+    if len(arguments) != 2:
+        raise SystemExit("usage: blender -b --python check-mesh-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 = mesh_report()
+    descriptor, temporary = tempfile.mkstemp(prefix="m16-mesh-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 = mesh_report()
+    finally:
+        pathlib.Path(temporary).unlink(missing_ok=True)
+    if before != after:
+        raise RuntimeError(f"mesh save/reopen drift: {before} != {after}")
+    report = {
+        "schemaVersion": 1,
+        "task": "M16-GAP-00014",
+        "operation": "MESH_DATABLOCK_DESKTOP",
+        "fixture": str(fixture),
+        "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(),
+        "mesh": 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"mesh-desktop-ok id={after['id']} vertices={after['vertexCount']} triangles={after['triangleCount']} saveReopen=exact")
+
+
+if __name__ == "__main__":
+    main()