Merge pull request #1714 from abhihjoshi:tendons

PiperOrigin-RevId: 651048034
Change-Id: If5b7cb55ff0007c3c6f932e62f068d1168778a33

python/mujoco/usd/lights.py

@@ -0,0 +1,81 @@
+# Copyright 2024 DeepMind Technologies Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Light handling for USD exporter."""
+
+from typing import Optional
+
+import numpy as np
+
+from pxr import Gf
+from pxr import Usd
+from pxr import UsdGeom
+from pxr import UsdLux
+
+
+class USDSphereLight:
+  """Class that handles the sphere lights in the USD scene."""
+
+  def __init__(
+      self, stage: Usd.Stage, obj_name: str, radius: Optional[float] = 0.3
+  ):
+    self.stage = stage
+
+    xform_path = f"/World/Light_Xform_{obj_name}"
+    light_path = f"{xform_path}/Light_{obj_name}"
+    self.usd_xform = UsdGeom.Xform.Define(stage, xform_path)
+    self.usd_light = UsdLux.SphereLight.Define(stage, light_path)
+    self.usd_prim = stage.GetPrimAtPath(light_path)
+
+    # we assume in mujoco that all lights are point lights
+    self.usd_light.GetRadiusAttr().Set(radius)
+    self.usd_light.GetTreatAsPointAttr().Set(False)
+    self.usd_light.GetNormalizeAttr().Set(True)
+
+    # defining ops required by update function
+    self.translate_op = self.usd_xform.AddTranslateOp()
+
+  def update(
+      self, pos: np.ndarray, intensity: int, color: np.ndarray, frame: int
+  ):
+    """Updates the attributes of a sphere light."""
+    self.translate_op.Set(Gf.Vec3d(pos.tolist()), frame)
+
+    if not np.any(pos):
+      intensity = 0
+
+    self.usd_light.GetIntensityAttr().Set(intensity)
+    self.usd_light.GetColorAttr().Set(Gf.Vec3d(color.tolist()))
+
+
+class USDDomeLight:
+  """Class that handles the dome lights in the USD scene."""
+
+  def __init__(self, stage: Usd.Stage, obj_name: str):
+    self.stage = stage
+
+    xform_path = f"/World/Light_Xform_{obj_name}"
+    light_path = f"{xform_path}/Light_{obj_name}"
+    self.usd_xform = UsdGeom.Xform.Define(stage, xform_path)
+    self.usd_light = UsdLux.DomeLight.Define(stage, light_path)
+    self.usd_prim = stage.GetPrimAtPath(light_path)
+
+    # we assume in mujoco that all lights are point lights
+    self.usd_light.GetNormalizeAttr().Set(True)
+
+  def update(self, intensity: int, color: np.ndarray):
+    """Updates the attributes of a dome light."""
+    self.usd_light.GetIntensityAttr().Set(intensity)
+    self.usd_light.GetExposureAttr().Set(0.0)
+    self.usd_light.GetColorAttr().Set(Gf.Vec3d(color.tolist()))