Checkpoint web parity through Chromium input tasks

tools/web/generate-obj-single-mesh-fixture.py

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+"""Generate the pinned Blender 5.2 single-Mesh OBJ fixture for M12-07A."""
+
+import hashlib
+import json
+import sys
+from pathlib import Path
+
+import bpy
+
+
+OBJ_NAME = "M12 OBJ Single Mesh"
+MATERIAL_NAMES = ("M12 OBJ Red", "M12 OBJ Blue")
+
+
+def sha256_file(path):
+    digest = hashlib.sha256()
+    with open(path, "rb") as handle:
+        for chunk in iter(lambda: handle.read(1024 * 1024), b""):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def text(value):
+    return value.decode("utf-8") if isinstance(value, bytes) else value
+
+
+def runtime_identity():
+    binary = Path(bpy.app.binary_path)
+    return {
+        "blenderVersion": text(bpy.app.version_string),
+        "versionTuple": list(bpy.app.version),
+        "buildDate": text(bpy.app.build_date),
+        "buildTime": text(bpy.app.build_time),
+        "buildHash": text(bpy.app.build_hash),
+        "buildBranch": text(bpy.app.build_branch),
+        "buildPlatform": text(bpy.app.build_platform),
+        "buildType": text(bpy.app.build_type),
+        "binarySha256": sha256_file(binary),
+    }
+
+
+def create_fixture():
+    bpy.ops.wm.read_factory_settings(use_empty=True)
+    mesh = bpy.data.meshes.new(OBJ_NAME + " Mesh")
+    mesh.from_pydata(
+        [(-1.0, -1.0, 0.0), (1.0, -1.0, 0.0), (1.0, 1.0, 0.0), (-1.0, 1.0, 0.0)],
+        [],
+        [(0, 1, 2), (0, 2, 3)],
+    )
+    mesh.update()
+    obj = bpy.data.objects.new(OBJ_NAME, mesh)
+    bpy.context.scene.collection.objects.link(obj)
+
+    uv_layer = mesh.uv_layers.new(name="UVMap")
+    uv_by_vertex = ((0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0))
+    for loop in mesh.loops:
+        uv_layer.data[loop.index].uv = uv_by_vertex[loop.vertex_index]
+
+    colors = ((0.8, 0.1, 0.05, 1.0), (0.05, 0.2, 0.85, 1.0))
+    for name, color in zip(MATERIAL_NAMES, colors):
+        material = bpy.data.materials.new(name)
+        material.diffuse_color = color
+        material.metallic = 0.0
+        material.roughness = 0.5
+        mesh.materials.append(material)
+    mesh.polygons[0].material_index = 0
+    mesh.polygons[1].material_index = 1
+    for polygon in mesh.polygons:
+        polygon.use_smooth = False
+
+    obj.select_set(True)
+    bpy.context.view_layer.objects.active = obj
+    return obj
+
+
+def export_obj(output_path):
+    result = bpy.ops.wm.obj_export(
+        filepath=str(output_path),
+        export_selected_objects=True,
+        apply_modifiers=False,
+        apply_transform=False,
+        export_eval_mode="DAG_EVAL_VIEWPORT",
+        export_uv=True,
+        export_normals=True,
+        export_colors=False,
+        export_materials=True,
+        export_pbr_extensions=False,
+        export_material_groups=True,
+        export_object_groups=False,
+        export_vertex_groups=False,
+        export_smooth_groups=False,
+        export_triangulated_mesh=False,
+        export_curves_as_nurbs=False,
+        global_scale=1.0,
+        forward_axis="NEGATIVE_Z",
+        up_axis="Y",
+        path_mode="RELATIVE",
+    )
+    if "FINISHED" not in result:
+        raise RuntimeError("Blender OBJ export did not finish: %s" % (result,))
+
+
+def number(value):
+    parsed = float(value)
+    return 0.0 if parsed == 0.0 else parsed
+
+
+def parse_obj(path):
+    positions = []
+    texcoords = []
+    normals = []
+    faces = []
+    material_libraries = []
+    objects = []
+    current_material = None
+    current_groups = []
+    for raw_line in path.read_text(encoding="utf-8").splitlines():
+        line = raw_line.strip()
+        if not line or line.startswith("#"):
+            continue
+        parts = line.split()
+        kind = parts[0]
+        if kind == "v":
+            positions.append([number(value) for value in parts[1:4]])
+        elif kind == "vt":
+            texcoords.append([number(value) for value in parts[1:3]])
+        elif kind == "vn":
+            normals.append([number(value) for value in parts[1:4]])
+        elif kind == "mtllib":
+            material_libraries.extend(parts[1:])
+        elif kind == "o":
+            objects.append(" ".join(parts[1:]))
+        elif kind == "g":
+            current_groups = parts[1:]
+        elif kind == "usemtl":
+            current_material = " ".join(parts[1:])
+        elif kind == "f":
+            vertices = []
+            for token in parts[1:]:
+                indices = token.split("/")
+                vertices.append({
+                    "position": int(indices[0]),
+                    "texcoord": int(indices[1]) if len(indices) > 1 and indices[1] else None,
+                    "normal": int(indices[2]) if len(indices) > 2 and indices[2] else None,
+                })
+            faces.append({"vertices": vertices, "material": current_material, "groups": list(current_groups)})
+    return {
+        "materialLibraries": material_libraries,
+        "objects": objects,
+        "positions": positions,
+        "texcoords": texcoords,
+        "normals": normals,
+        "faces": faces,
+    }
+
+
+def parse_mtl(path):
+    materials = []
+    current = None
+    for raw_line in path.read_text(encoding="utf-8").splitlines():
+        line = raw_line.strip()
+        if not line or line.startswith("#"):
+            continue
+        parts = line.split()
+        if parts[0] == "newmtl":
+            current = {"name": " ".join(parts[1:]), "properties": {}}
+            materials.append(current)
+        elif current is not None:
+            values = parts[1:]
+            current["properties"][parts[0]] = [number(value) for value in values] if all_value_numbers(values) else " ".join(values)
+    return materials
+
+
+def all_value_numbers(values):
+    if not values:
+        return False
+    try:
+        for value in values:
+            float(value)
+        return True
+    except ValueError:
+        return False
+
+
+def main(output_dir, report_path):
+    output_dir = Path(output_dir).resolve()
+    report_path = Path(report_path).resolve()
+    output_dir.mkdir(parents=True, exist_ok=True)
+    report_path.parent.mkdir(parents=True, exist_ok=True)
+    obj_path = output_dir / "single-mesh.obj"
+    create_fixture()
+    export_obj(obj_path)
+    mtl_path = obj_path.with_suffix(".mtl")
+    if not mtl_path.exists():
+        raise RuntimeError("Blender OBJ export did not write the MTL sidecar")
+    semantic = parse_obj(obj_path)
+    semantic["materials"] = parse_mtl(mtl_path)
+    report = {
+        "schemaVersion": 1,
+        "task": "M12-07A",
+        "operation": "DESKTOP_OBJ_SINGLE_MESH_FIXTURE",
+        "runtime": runtime_identity(),
+        "sourceAnchor": "blender-5.2.0/source/blender/io/wavefront_obj",
+        "operator": "wm.obj_export",
+        "settings": {
+            "forwardAxis": "NEGATIVE_Z",
+            "upAxis": "Y",
+            "globalScale": 1.0,
+            "exportUV": True,
+            "exportNormals": True,
+            "exportMaterials": True,
+            "exportMaterialGroups": True,
+        },
+        "files": [
+            {"name": obj_path.name, "byteLength": obj_path.stat().st_size, "sha256": sha256_file(obj_path)},
+            {"name": mtl_path.name, "byteLength": mtl_path.stat().st_size, "sha256": sha256_file(mtl_path)},
+        ],
+        "semantic": semantic,
+        "nextTask": "M12-07B",
+    }
+    report_path.write_text(json.dumps(report, indent=2, sort_keys=True) + "\n", encoding="utf-8")
+    print(
+        "obj-single-mesh-fixture-generated positions=%s texcoords=%s normals=%s faces=%s materials=%s next=%s"
+        % (
+            len(semantic["positions"]),
+            len(semantic["texcoords"]),
+            len(semantic["normals"]),
+            len(semantic["faces"]),
+            len(semantic["materials"]),
+            report["nextTask"],
+        )
+    )
+
+
+if __name__ == "__main__":
+    args = sys.argv[sys.argv.index("--") + 1 :] if "--" in sys.argv else []
+    if len(args) != 2:
+        raise SystemExit("usage: blender --background --python generate-obj-single-mesh-fixture.py -- OUTPUT_DIR REPORT")
+    main(args[0], args[1])