feat: tool to construct XML

scripts/analysis/dump_mjcf.py

@@ -0,0 +1,186 @@
+#!/usr/bin/env python3
+"""
+Dump MJCF XML for a brittle-star morphology using the project's Hydra configs.
+
+Usage examples:
+
+  # Use a named morphology config from configs/morphology (Hydra style)
+  uv run python scripts/analysis/dump_mjcf.py morphology=3_arms
+
+  # Use a morphology override YAML (same key as simulation.morphology_override)
+  uv run python scripts/analysis/dump_mjcf.py \
+    simulation.morphology_override=configs/morphology/3_arms.yaml
+
+Output path:
+    Provide `dump_out=path/to/file.xml` on the command line, otherwise writes `morphology.xml` in
+    current directory.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+import sys
+import xml.etree.ElementTree as ET
+
+import hydra
+from omegaconf import DictConfig, OmegaConf
+
+from brittle_star_project.configs.main_config import BrittleStarConfig
+from brittle_star_project.configs.register_configs import register_configs
+from brittle_star_project.environment.env_config import MorphologyConfig
+from brittle_star_project.environment.factory import BrittleStarEnvFactory
+
+
+def try_serialize(obj):
+    """Try multiple common accessors to obtain an XML string from the morphology object."""
+    candidates = [
+        "to_xml_string",
+        "to_xml",
+        "to_string",
+        "to_mjcf",
+        "to_mjcf_string",
+        "get_mjcf",
+        "get_mjcf_str",
+        "get_mjcf_assets",
+        "export_to_xml_with_assets",
+        "get_xml",
+        "xml",
+        "mjcf",
+        "mjcf_model",
+        "mjcf_body",
+        "model",
+        "root",
+    ]
+
+    def normalize(out):
+        if out is None:
+            return None
+        # lxml element
+        try:
+            import lxml.etree as lxml_et
+
+            if isinstance(out, lxml_et._Element):
+                return lxml_et.tostring(out, encoding="unicode")
+        except Exception:
+            pass
+
+        if isinstance(out, ET.Element):
+            return ET.tostring(out, encoding="unicode")
+
+        if isinstance(out, bytes):
+            try:
+                return out.decode()
+            except Exception:
+                return None
+
+        if hasattr(out, "toxml") and callable(out.toxml):
+            try:
+                return out.toxml()
+            except Exception:
+                pass
+
+        try:
+            s = str(out)
+            if s.lstrip().startswith("<"):
+                return s
+            return s
+        except Exception:
+            return None
+
+    for name in candidates:
+        attr = getattr(obj, name, None)
+        if callable(attr):
+            try:
+                out = attr()
+            except Exception:
+                out = None
+            if out:
+                norm = normalize(out)
+                if norm:
+                    return norm
+        elif attr is not None:
+            norm = normalize(attr)
+            if norm:
+                return norm
+
+    if hasattr(obj, "mjcf"):
+        nested = getattr(obj, "mjcf")
+        if nested is not None:
+            return try_serialize(nested)
+
+    return None
+
+
+@hydra.main(config_path="../../configs", config_name="main_config", version_base="1.3")
+def main(dict_cfg: DictConfig) -> None:
+    # Compose typed config like the rest of the project
+    cfg = OmegaConf.to_object(OmegaConf.merge(OmegaConf.structured(BrittleStarConfig), dict_cfg))
+
+    # Check for a simulation morphology override (points to a YAML file)
+    sim_override = None
+    try:
+        sim_override = dict_cfg.get("simulation", {}).get("morphology_override", None)
+    except Exception:
+        sim_override = getattr(getattr(cfg, "simulation", None), "morphology_override", None)
+
+    if sim_override:
+        override_path = Path(hydra.utils.to_absolute_path(sim_override))
+        if not override_path.exists():
+            raise FileNotFoundError(f"Could not find morphology override YAML at {override_path}")
+        import yaml
+
+        with open(override_path, "r") as f:
+            override_dict = yaml.safe_load(f)
+        env_morphology = OmegaConf.to_object(
+            OmegaConf.merge(OmegaConf.structured(MorphologyConfig), override_dict)
+        )
+    else:
+        env_morphology = cfg.morphology
+
+    # Ensure we have a MorphologyConfig instance
+    if isinstance(env_morphology, dict):
+        morph_cfg = MorphologyConfig(**env_morphology)
+    else:
+        morph_cfg = env_morphology
+
+    # Build morphology via project factory (same as runtime)
+    morph = BrittleStarEnvFactory.create_morphology(morph_cfg)
+
+    xml_text = try_serialize(morph)
+    if xml_text is None and hasattr(morph, "mjcf"):
+        xml_text = try_serialize(morph.mjcf)
+
+    if xml_text is None:
+        raise RuntimeError(
+            "Failed to serialize morphology to MJCF/XML. Inspect the `morph` object interactively."
+        )
+
+    # Prefer explicit CLI override `dump_out=...` if provided, otherwise choose a sensible default.
+    dump_out = None
+    try:
+        dump_out = dict_cfg.get("dump_out", None)
+    except Exception:
+        dump_out = None
+
+    if dump_out is None:
+        # If the user passed a morphology group on the CLI (e.g. morphology=3_arms),
+        # use a descriptive default path under `runs/morphologies/`.
+        morph_name = None
+        for a in sys.argv[1:]:
+            if a.startswith("morphology="):
+                morph_name = a.split("=", 1)[1]
+                break
+
+        default_out = f"runs/morphologies/{morph_name}.xml" if morph_name else "morphology.xml"
+        out_path = Path(hydra.utils.to_absolute_path(default_out))
+    else:
+        out_path = Path(hydra.utils.to_absolute_path(str(dump_out)))
+
+    out_path.parent.mkdir(parents=True, exist_ok=True)
+    out_path.write_text(xml_text)
+    print(f"Wrote MJCF XML to {out_path}")
+
+
+if __name__ == "__main__":
+    register_configs()
+    main()

tests/test_morphology_render.py

@@ -14,7 +14,7 @@ from brittle_star_project.environment.BrittleStarJaxEnvWrapper import BrittleSta
 
 @pytest.mark.skipif(os.getenv("CI") == "true", reason="No OpenGL display in CI")
 def test_render_morphologies():
-    base_dir = "runs/renders"
+    base_dir = "runs/morphologies"
     os.makedirs(base_dir, exist_ok=True)
 
     # --- 1. Full 5-Arm Morphology ---
@@ -34,7 +34,7 @@ def test_render_morphologies():
     renderer_full = mujoco.Renderer(model=model_full)
     renderer_full.update_scene(data_full, camera=1)
     pixels_full = renderer_full.render()
-    image_path = os.path.join(base_dir, "full_5_arm.png")
+    image_path = os.path.join(base_dir, "5_arm.png")
     Image.fromarray(pixels_full).save(image_path)
     print(f"Generated full morphology render: {image_path}")