Merge pull request #419 from aftersomemath:simulate-python

PiperOrigin-RevId: 487496285 Change-Id: I17d15bd2a3886e5ce1631f4eb78afa94830d08cc
2022-11-10 04:12:34 -08:00
parent 0b45129ca4 8cc983af5b
commit f7b256de91
14 changed files with 611 additions and 134 deletions
@@ -6,6 +6,12 @@ Changelog
 Upcoming version (not yet released)
 -----------------------------------

+Python bindings
+^^^^^^^^^^^^^^^
+
+- The ``simulate`` GUI is now available through the ``mujoco`` Python package. See :ref:`documentation<PyGUI>` for
+  details. (Contribution by `Levi Burner <https://github.com/aftersomemath>`_.)
+
 General
 ^^^^^^^

@@ -152,6 +152,38 @@ Minimal example
       mujoco.mj_step(model, data)
       print(data.geom_xpos)

+.. _PyGUI:
+
+Interactive visualizer
+----------------------
+
+MuJoCo's interactive GUI (also known as the ``simulate`` application) is available as part of the Python package.
+Three distinct use cases are supported:
+
+- Launching as a standalone application:
+
+   * ``python -m mujoco.simulate`` launches an empty visualization session, where a model can be loaded by drag-and-drop.
+   * ``python -m mujoco.simulate --mjcf=/path/to/some/mjcf.xml`` launches a visualization session for the specified
+     model file.
+
+- Launching from a Python program/script -- import the module via ``from mujoco import simulate`` and launch the GUI
+  using one of the following invocations:
+
+   * ``simulate.launch()`` launches an empty visualization session, where a model can be loaded by drag-and-drop.
+   * ``simulate.launch(model)`` launches a visualzation session for the given ``mjModel`` where the visualizer
+     internally creates its own instance of ``mjData``
+   * ``simulate.launch(model, data)`` is the same as above, except that the visualizer operates directly on the given
+     ``mjData`` instance -- upon exit the ``data`` object will have been modified.
+
+- Launching from an interactive Python session (aka REPL): when working interactively either in a ``python`` or
+  ``ipython`` shell, the visualizer can be launched in a "passive" mode via ``simulate.launch_repl(model, data)``, where
+  the user remains in full control of modifying or stepping the physics. In this mode, the user can interact with the
+  visualizer using the mouse and keyboard as usual, however the physics will be frozen unless the user explicitly calls
+  ``mj_step`` (or perform any other modification of the ``mjData`` or ``mjModel``) in the REPL terminal. Note that since
+  the visualizer does not modify ``mjData`` in this mode, mouse-drag perturbations will not work unless the user
+  explicitly handles incoming GUI perturbation events in the REPL session.
+
+
 .. _PyNamed:

 Named access
@@ -1,3 +1,3 @@
 include LICENSE *.md
-recursive-include mujoco *.h *.cc CMakeLists.txt
+recursive-include mujoco *.h *.cc *.mm CMakeLists.txt Simulate*.cmake
 recursive-include cmake *.cmake
@@ -53,6 +53,9 @@ cp "${package_dir}"/../LICENSE .
 mkdir cmake
 cp "${package_dir}"/../cmake/*.cmake cmake

+# Copy over Simulate source code.
+cp -r "${package_dir}"/../simulate mujoco
+
 python setup.py sdist --formats=gztar
 tar -tf dist/mujoco-*.tar.gz
 popd
@@ -119,6 +119,7 @@ if(NOT TARGET mujoco)
    )
    set_target_properties(mujoco PROPERTIES IMPORTED_SONAME "${MUJOCO_SONAME}")
  endif()
+  add_library(mujoco::mujoco ALIAS mujoco)
 endif()

 # ==================== ABSEIL ==================================================
@@ -190,6 +191,9 @@ findorfetch(
 )

 # ==================== MUJOCO PYTHON BINDINGS ==================================
+set(SIMULATE_BUILD_EXECUTABLE OFF)
+set(SIMULATE_GLFW_DYNAMIC_SYMBOLS ON)
+add_subdirectory(simulate)

 add_subdirectory(util)

@@ -376,6 +380,14 @@ target_link_libraries(
          structs_header
 )

+mujoco_pybind11_module(_simulate simulate.cc)
+target_link_libraries(
+  _simulate
+  PRIVATE mujoco
+          mujoco::libsimulate
+          raw
+          structs_header)
+
 set(LIBRARIES_FOR_WHEEL
    "$<TARGET_FILE:_callbacks>"
    "$<TARGET_FILE:_constants>"
@@ -384,6 +396,7 @@ set(LIBRARIES_FOR_WHEEL
    "$<TARGET_FILE:_functions>"
    "$<TARGET_FILE:_render>"
    "$<TARGET_FILE:_rollout>"
+    "$<TARGET_FILE:_simulate>"
    "$<TARGET_FILE:_structs>"
    "$<TARGET_FILE:mujoco>"
 )
@@ -411,6 +424,7 @@ if(MUJOCO_PYTHON_MAKE_WHEEL)
    _functions
    _render
    _rollout
+    _simulate
    _structs
    mujoco
  )
@@ -0,0 +1,143 @@
+// Copyright 2022 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.
+
+#include <cstdint>
+#include <cstring>
+#include <string>
+
+#include <simulate.h>
+#include "raw.h"
+#include "structs.h"
+#include <pybind11/detail/common.h>
+#include <pybind11/pybind11.h>
+
+namespace mujoco::python {
+namespace {
+PYBIND11_MODULE(_simulate, pymodule) {
+  namespace py = ::pybind11;
+  using SimulateMutex = decltype(mujoco::Simulate::mtx);
+
+  py::class_<SimulateMutex>(pymodule, "SimulateMutex")
+      .def(
+          "__enter__", [](SimulateMutex& mtx) { mtx.lock(); },
+          py::call_guard<py::gil_scoped_release>())
+      .def(
+          "__exit__",
+          [](SimulateMutex& mtx, py::handle, py::handle, py::handle) {
+            mtx.unlock();
+          },
+          py::call_guard<py::gil_scoped_release>());
+
+  py::class_<mujoco::Simulate>(pymodule, "Simulate")
+      .def(py::init<>())
+      .def(
+          "renderloop",
+          [](mujoco::Simulate& simulate) { simulate.renderloop(); },
+          py::call_guard<py::gil_scoped_release>())
+      .def(
+          "load",
+          [](mujoco::Simulate& simulate, MjModelWrapper& m, MjDataWrapper& d) {
+            simulate.load("", m.get(), d.get());
+          },
+          py::call_guard<py::gil_scoped_release>())
+      .def("applyposepertubations", &mujoco::Simulate::applyposepertubations,
+           py::call_guard<py::gil_scoped_release>())
+      .def("applyforceperturbations",
+           &mujoco::Simulate::applyforceperturbations,
+           py::call_guard<py::gil_scoped_release>())
+
+      .def(
+          "lock",
+          [](mujoco::Simulate& simulate) -> SimulateMutex& {
+            return simulate.mtx;
+          },
+          py::call_guard<py::gil_scoped_release>(),
+          py::return_value_policy::reference)
+      .def_readonly("ctrlnoisestd", &mujoco::Simulate::ctrlnoisestd,
+                    py::call_guard<py::gil_scoped_release>())
+      .def_readonly("ctrlnoiserate", &mujoco::Simulate::ctrlnoiserate,
+                    py::call_guard<py::gil_scoped_release>())
+
+      .def_readonly("real_time_index", &mujoco::Simulate::realTimeIndex,
+                    py::call_guard<py::gil_scoped_release>())
+      .def_readwrite("speed_changed", &mujoco::Simulate::speedChanged,
+                     py::call_guard<py::gil_scoped_release>())
+      .def_readwrite("measured_slowdown", &mujoco::Simulate::measuredSlowdown,
+                     py::call_guard<py::gil_scoped_release>())
+      .def_readonly("refresh_rate", &mujoco::Simulate::refreshRate,
+                    py::call_guard<py::gil_scoped_release>())
+
+      .def_readonly("busywait", &mujoco::Simulate::busywait,
+                    py::call_guard<py::gil_scoped_release>())
+      .def_readonly("run", &mujoco::Simulate::run,
+                    py::call_guard<py::gil_scoped_release>())
+
+      .def_property_readonly(
+          "exitrequest",
+          [](mujoco::Simulate& simulate) {
+            return simulate.exitrequest.load();
+          },
+          py::call_guard<py::gil_scoped_release>())
+
+      .def_property_readonly(
+          "uiloadrequest",
+          [](mujoco::Simulate& simulate) {
+            return simulate.uiloadrequest.load();
+          },
+          py::call_guard<py::gil_scoped_release>())
+      .def(
+          "uiloadrequest_decrement",
+          [](mujoco::Simulate& simulate) {
+            simulate.uiloadrequest.fetch_sub(1);
+          },
+          py::call_guard<py::gil_scoped_release>())
+
+      .def_property(
+          "droploadrequest",
+          [](mujoco::Simulate& simulate) {
+            return simulate.droploadrequest.load();
+          },
+          [](mujoco::Simulate& simulate, bool droploadrequest) {
+            simulate.droploadrequest.store(droploadrequest);
+          },
+          py::call_guard<py::gil_scoped_release>())
+      .def_property_readonly(
+          "dropfilename",
+          [](mujoco::Simulate& simulate) -> std::string {
+            return simulate.dropfilename;
+          },
+          py::call_guard<py::gil_scoped_release>())
+      .def_property_readonly(
+          "filename",
+          [](mujoco::Simulate& simulate) -> std::string {
+            return simulate.filename;
+          },
+          py::call_guard<py::gil_scoped_release>())
+      .def_property(
+          "load_error",
+          [](mujoco::Simulate& simulate) -> std::string {
+            return simulate.loadError;
+          },
+          [](mujoco::Simulate& simulate, const std::string& error) {
+            std::strncpy(simulate.loadError, error.c_str(),
+                         simulate.kMaxFilenameLength);
+          });
+
+  pymodule.def("setglfwdlhandle", [](std::uintptr_t dlhandle) {
+    mujoco::setglfwdlhandle(reinterpret_cast<void*>(dlhandle));
+  });
+}
+
+}  // namespace
+}  // namespace mujoco::python
@@ -0,0 +1,266 @@
+# Copyright 2022 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.
+# ==============================================================================
+"""Python bindings for the Simulate GUI."""
+
+import atexit
+import code
+import inspect
+import math
+import os
+import threading
+import time
+import typing
+from typing import Callable, Optional
+
+import glfw
+import mujoco
+from mujoco import _simulate
+import numpy as np
+
+if not glfw._glfw:  # pylint: disable=protected-access
+  raise RuntimeError('GLFW dynamic library handle is not available')
+else:
+  _simulate.setglfwdlhandle(glfw._glfw._handle)  # pylint: disable=protected-access
+
+# Logarithmically spaced realtime slow-down coefficients (percent).
+PERCENT_REALTIME = (
+    100, 80, 66, 50, 40, 33, 25, 20, 16, 13,
+    10, 8, 6.6, 5, 4, 3.3, 2.5, 2, 1.6, 1.3,
+    1, 0.8, 0.66, 0.5, 0.4, 0.33, 0.25, 0.2, 0.16, 0.13,
+    0.1
+)
+
+# Maximum time mis-alignment before re-sync.
+MAX_SYNC_MISALIGN = 0.1
+
+# Fraction of refresh available for simulation.
+SIM_REFRESH_FRACTION = 0.7
+
+CallbackType = Callable[[mujoco.MjModel, mujoco.MjData], None]
+
+Simulate = _simulate.Simulate
+
+
+def _reload_from_file(simulate: Simulate, filename: str):
+  """Loads an MJCF model into the Simulate GUI."""
+  try:
+    m = mujoco.MjModel.from_xml_path(filename)
+  except mujoco.FatalError as e:
+    m = None
+    simulate.load_error = str(e)
+
+  if m is not None:
+    d = mujoco.MjData(m)
+    simulate.load(m, d)
+    mujoco.mj_forward(m, d)
+  else:
+    d = None
+
+  return m, d
+
+
+def _physics_loop(simulate: Simulate,
+                  m: Optional[mujoco.MjModel],
+                  d: Optional[mujoco.MjData]):
+  """Physics loop for the Simulate GUI, to be run in a separate thread."""
+  ctrlnoise = None
+  if m is not None:
+    ctrlnoise = np.zeros((m.nu,))
+
+  # CPU-sim synchronization point.
+  synccpu = 0.0
+  syncsim = 0.0
+
+  # Run until asked to exit.
+  while not simulate.exitrequest:
+    if simulate.droploadrequest:
+      simulate.droploadrequest = 0
+      new_m, new_d = _reload_from_file(simulate, simulate.dropfilename)
+      if new_m is not None:
+        m = new_m
+        d = new_d
+        ctrlnoise = np.zeros((m.nu,))
+
+    if simulate.uiloadrequest:
+      simulate.uiloadrequest_decrement()
+      new_m, new_d = _reload_from_file(simulate, simulate.dropfilename)
+      if new_m is not None:
+        m = new_m
+        d = new_d
+        ctrlnoise = np.zeros((m.nu,))
+
+    # Sleep for 1 ms or yield, to let main thread run.
+    if simulate.run != 0 and simulate.busywait != 0:
+      time.sleep(0)
+    else:
+      time.sleep(0.001)
+
+    with simulate.lock():
+      if m is not None:
+        assert d is not None
+        if simulate.run:
+          # Record CPU time at start of iteration.
+          startcpu = glfw.get_time()
+
+          elapsedcpu = startcpu - synccpu
+          elapsedsim = d.time - syncsim
+
+          # Inject noise.
+          if simulate.ctrlnoisestd != 0.0:
+            # Convert rate and scale to discrete time (Ornstein–Uhlenbeck).
+            rate = math.exp(-m.opt.timestep / simulate.ctrlnoiserate)
+            scale = simulate.ctrlnoisestd * math.sqrt(1 - rate * rate)
+
+            for i in range(m.nu):
+              # Update noise.
+              ctrlnoise[i] = (
+                  rate * ctrlnoise[i] + scale * mujoco.mju_standardNormal(None))
+
+              # Apply noise.
+              d.ctrl[i] = ctrlnoise[i]
+
+          # Requested slow-down factor.
+          slowdown = 100 / PERCENT_REALTIME[simulate.real_time_index]
+
+          # Misalignment: distance from target sim time > MAX_SYNC_MISALIGN.
+          misaligned = abs(elapsedcpu / slowdown -
+                           elapsedsim) > MAX_SYNC_MISALIGN
+
+          # Out-of-sync (for any reason): reset sync times, step.
+          if (elapsedsim < 0 or elapsedcpu < 0 or synccpu == 0 or misaligned or
+              simulate.speed_changed):
+            # Re-sync.
+            synccpu = startcpu
+            syncsim = d.time
+            simulate.speed_changed = False
+
+            # Clear old perturbations, apply new.
+            d.xfrc_applied[:, :] = 0
+            simulate.applyposepertubations(0)  # Move mocap bodies only.
+            simulate.applyforceperturbations()
+
+            # Run single step, let next iteration deal with timing.
+            mujoco.mj_step(m, d)
+
+          # In-sync: step until ahead of cpu.
+          else:
+            measured = False
+            prevsim = d.time
+            refreshtime = SIM_REFRESH_FRACTION / simulate.refresh_rate
+            # Step while sim lags behind CPU and within refreshtime.
+            while (((d.time - syncsim) * slowdown <
+                    (glfw.get_time() - synccpu)) and
+                   ((glfw.get_time() - startcpu) < refreshtime)):
+              # Measure slowdown before first step.
+              if not measured and elapsedsim:
+                simulate.measured_slowdown = elapsedcpu / elapsedsim
+                measured = True
+
+              # Clear old perturbations, apply new.
+              d.xfrc_applied[:, :] = 0
+              simulate.applyposepertubations(0)  # Move mocap bodies only.
+              simulate.applyforceperturbations()
+
+              # Call mj_step.
+              mujoco.mj_step(m, d)
+
+              # Break if reset.
+              if d.time < prevsim:
+                break
+        else:  # simulate.run is False: GUI is paused.
+          # Apply pose perturbation.
+          simulate.applyposepertubations(1)  # Move mocap and dynamic bodies.
+
+          # Run mj_forward, to update rendering and joint sliders.
+          mujoco.mj_forward(m, d)
+
+
+def launch(model: Optional[mujoco.MjModel] = None,
+           data: Optional[mujoco.MjData] = None,
+           *,
+           run_physics_thread: bool = True) -> None:
+  """Launches the Simulate GUI."""
+  if model is None and data is not None:
+    raise ValueError('mjData is specified but mjModel is not')
+  elif model is not None and data is None:
+    data = mujoco.MjData(model)
+
+  # The simulate object encapsulates the UI.
+  simulate = Simulate()
+
+  # Initialize GLFW.
+  if not glfw.init():
+    raise mujoco.FatalError('could not initialize GLFW')
+
+  atexit.register(glfw.terminate)
+
+  if run_physics_thread:
+    physics_thread = threading.Thread(
+        target=_physics_loop, args=(simulate, model, data))
+    physics_thread.start()
+
+  # Load the initial model, if one is given.
+  if model is not None:
+    t = threading.Thread(target=simulate.load, args=(model, data))
+    t.start()
+    del t
+
+  simulate.renderloop()
+
+  if run_physics_thread:
+    physics_thread.join()
+
+
+def launch_repl(model: mujoco.MjModel, data: mujoco.MjData) -> None:
+  """EXPERIMENTAL FEATURE: Launches the Simulate GUI in REPL mode."""
+  if typing.TYPE_CHECKING:
+    launch(model, data, run_physics_thread=False)
+    return
+
+  try:
+    import IPython  # pylint: disable=g-import-not-at-top
+    has_ipython = True
+  except ImportError:
+    has_ipython = False
+
+  def start_shell(global_variables):
+    if has_ipython and IPython.get_ipython() is not None:
+      locals().update(global_variables)
+      IPython.embed()
+    else:
+      code.InteractiveConsole(locals=global_variables).interact()
+
+  repl_thread = threading.Thread(
+      target=start_shell, args=(inspect.stack()[1][0].f_globals,))
+  repl_thread.start()
+  launch(model, data, run_physics_thread=False)
+  repl_thread.join()
+
+
+if __name__ == '__main__':
+  from absl import app  # pylint: disable=g-import-not-at-top
+  from absl import flags  # pylint: disable=g-import-not-at-top
+
+  _MJCF_PATH = flags.DEFINE_string('mjcf', None, 'Path to MJCF file.')
+
+  def main(argv) -> None:
+    del argv
+    if _MJCF_PATH.value is not None:
+      model = mujoco.MjModel.from_xml_path(os.path.expanduser(_MJCF_PATH.value))
+      launch(model)
+    else:
+      launch()
+
+  app.run(main)
@@ -70,7 +70,6 @@ def get_external_lib_patterns():
  else:
    return ['libmujoco.so.*']

-
 def get_plugin_lib_patterns():
  if platform.system() == 'Windows':
    return ['*.dll']
@@ -322,6 +321,7 @@ setup(
        CMakeExtension('mujoco._functions'),
        CMakeExtension('mujoco._render'),
        CMakeExtension('mujoco._rollout'),
+        CMakeExtension('mujoco._simulate'),
        CMakeExtension('mujoco._structs'),
    ],
    python_requires='>=3.7',
@@ -41,6 +41,9 @@ if(APPLE)
  enable_language(OBJCXX)
 endif()

+option(SIMULATE_BUILD_EXECUTABLE "Build the simulate executable binary." ON)
+option(SIMULATE_GLFW_DYNAMIC_SYMBOLS "Whether to resolve GLFW symbols dynamically." OFF)
+
 # Check if we are building as standalone project.
 set(SIMULATE_STANDALONE OFF)
 set(_INSTALL_SIMULATE ON)
@@ -114,7 +117,8 @@ target_sources(
 target_include_directories(libsimulate PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_compile_definitions(libsimulate PUBLIC MJSIMULATE_STATIC)
 target_compile_options(libsimulate PUBLIC ${MUJOCO_SIMULATE_COMPILE_OPTIONS})
-target_link_libraries(libsimulate PUBLIC glfw lodepng mujoco::mujoco)
+target_link_libraries(libsimulate PUBLIC lodepng mujoco::mujoco)
+target_include_directories(libsimulate PUBLIC $<TARGET_PROPERTY:glfw,INTERFACE_INCLUDE_DIRECTORIES>)
 target_link_options(libsimulate PRIVATE ${MUJOCO_SIMULATE_LINK_OPTIONS})

 if(APPLE)
@@ -122,126 +126,132 @@ if(APPLE)
  target_link_libraries(libsimulate PUBLIC "-framework Cocoa")
 endif()

+if(SIMULATE_GLFW_DYNAMIC_SYMBOLS)
+  target_compile_definitions(libsimulate PUBLIC mjGLFW_DYNAMIC_SYMBOLS)
+endif()
+
 # Build simulate executable
-if(APPLE)
-  set(SIMULATE_RESOURCE_FILES ${CMAKE_CURRENT_SOURCE_DIR}/../dist/mujoco.icns)
-elseif(WIN32)
-  set(SIMULATE_RESOURCE_FILES ${CMAKE_CURRENT_SOURCE_DIR}/../dist/simulate.rc)
-else()
-  set(SIMULATE_RESOURCE_FILES "")
-endif()
+if(SIMULATE_BUILD_EXECUTABLE)
+  if(APPLE)
+    set(SIMULATE_RESOURCE_FILES ${CMAKE_CURRENT_SOURCE_DIR}/../dist/mujoco.icns)
+  elseif(WIN32)
+    set(SIMULATE_RESOURCE_FILES ${CMAKE_CURRENT_SOURCE_DIR}/../dist/simulate.rc)
+  else()
+    set(SIMULATE_RESOURCE_FILES "")
+  endif()

-add_executable(simulate main.cc array_safety.h ${SIMULATE_RESOURCE_FILES})
-target_compile_options(simulate PUBLIC ${MUJOCO_SIMULATE_COMPILE_OPTIONS})
-if(WIN32)
-  add_custom_command(
-    TARGET simulate
-    PRE_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/../dist/mujoco.ico
-            ${CMAKE_CURRENT_SOURCE_DIR}
-    POST_BUILD
-    COMMAND ${CMAKE_COMMAND} -E rm ${CMAKE_CURRENT_SOURCE_DIR}/mujoco.ico
-  )
-endif()
+  add_executable(simulate main.cc array_safety.h ${SIMULATE_RESOURCE_FILES})
+  target_compile_options(simulate PUBLIC ${MUJOCO_SIMULATE_COMPILE_OPTIONS})
+  if(WIN32)
+    add_custom_command(
+      TARGET simulate
+      PRE_BUILD
+      COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/../dist/mujoco.ico
+              ${CMAKE_CURRENT_SOURCE_DIR}
+      POST_BUILD
+      COMMAND ${CMAKE_COMMAND} -E rm ${CMAKE_CURRENT_SOURCE_DIR}/mujoco.ico
+    )
+  endif()

-target_link_libraries(
-  simulate
-  libsimulate
-  mujoco::mujoco
-  glfw
-  Threads::Threads
-  lodepng
-)
-
-target_link_options(simulate PRIVATE ${MUJOCO_SIMULATE_LINK_OPTIONS})
-
-if(APPLE AND MUJOCO_BUILD_MACOS_FRAMEWORKS)
-  set_target_properties(
+  target_link_libraries(
    simulate
-    PROPERTIES INSTALL_RPATH @executable_path/../Frameworks
-               BUILD_WITH_INSTALL_RPATH TRUE
-               RESOURCE ${SIMULATE_RESOURCE_FILES}
-               MACOSX_BUNDLE TRUE
-               MACOSX_BUNDLE_INFO_PLIST ${CMAKE_CURRENT_SOURCE_DIR}/../dist/Info.plist.simulate.in
-               MACOSX_BUNDLE_BUNDLE_NAME "MuJoCo"
-               MACOSX_BUNDLE_GUI_IDENTIFIER "org.mujoco.mujoco"
-               MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
-               MACOSX_BUNDLE_INFO_STRING ${PROJECT_VERSION}
-               MACOSX_BUNDLE_LONG_VERSION_STRING ${PROJECT_VERSION}
-               MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION}
-               MACOSX_BUNDLE_ICON_FILE "mujoco.icns"
-               MACOSX_BUNDLE_COPYRIGHT "Copyright 2021 DeepMind Technologies Limited."
+    libsimulate
+    mujoco::mujoco
+    glfw
+    Threads::Threads
+    lodepng
  )

-  macro(embed_in_bundle target)
-    add_dependencies(${target} simulate)
+  target_link_options(simulate PRIVATE ${MUJOCO_SIMULATE_LINK_OPTIONS})
+
+  if(APPLE AND MUJOCO_BUILD_MACOS_FRAMEWORKS)
    set_target_properties(
-      ${target}
+      simulate
      PROPERTIES INSTALL_RPATH @executable_path/../Frameworks
                 BUILD_WITH_INSTALL_RPATH TRUE
-                 RUNTIME_OUTPUT_DIRECTORY $<TARGET_FILE_DIR:simulate>
+                 RESOURCE ${SIMULATE_RESOURCE_FILES}
+                 MACOSX_BUNDLE TRUE
+                 MACOSX_BUNDLE_INFO_PLIST ${CMAKE_CURRENT_SOURCE_DIR}/../dist/Info.plist.simulate.in
+                 MACOSX_BUNDLE_BUNDLE_NAME "MuJoCo"
+                 MACOSX_BUNDLE_GUI_IDENTIFIER "org.mujoco.mujoco"
+                 MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
+                 MACOSX_BUNDLE_INFO_STRING ${PROJECT_VERSION}
+                 MACOSX_BUNDLE_LONG_VERSION_STRING ${PROJECT_VERSION}
+                 MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION}
+                 MACOSX_BUNDLE_ICON_FILE "mujoco.icns"
+                 MACOSX_BUNDLE_COPYRIGHT "Copyright 2021 DeepMind Technologies Limited."
    )
-  endmacro()

-  # Embed mujoco.framework inside the App bundle ane move the icon file over too.
-  add_custom_command(
-    TARGET simulate
-    POST_BUILD
-    COMMAND mkdir -p $<TARGET_FILE_DIR:simulate>/../Frameworks
-    COMMAND rm -rf $<TARGET_FILE_DIR:simulate>/../Frameworks/mujoco.framework
-    COMMAND cp -a $<TARGET_FILE_DIR:mujoco::mujoco>/../../../mujoco.framework
-            $<TARGET_FILE_DIR:simulate>/../Frameworks/
-    # Delete the symlink and the TBD, otherwise we can't sign and notarize.
-    COMMAND rm -rf $<TARGET_FILE_DIR:simulate>/../Frameworks/mujoco.framework/mujoco.tbd
-    COMMAND rm -rf
-            $<TARGET_FILE_DIR:simulate>/../Frameworks/mujoco.framework/Versions/A/libmujoco.dylib
-  )
-endif()
-
-# Do not install if macOS Bundles are created as RPATH is managed manually there.
-if(APPLE AND MUJOCO_BUILD_MACOS_FRAMEWORKS)
-  set(_INSTALL_SIMULATE OFF)
-endif()
-
-if(_INSTALL_SIMULATE)
-
-  include(TargetAddRpath)
-
-  # Add support to RPATH for the samples.
-  target_add_rpath(
-    TARGETS
-    simulate
-    INSTALL_DIRECTORY
-    "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}"
-    LIB_DIRS
-    "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}"
-    DEPENDS
-    MUJOCO_ENABLE_RPATH
-  )
-
-  install(
-    TARGETS simulate
-    EXPORT ${PROJECT_NAME}
-    RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT simulate
-    LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT simulate
-    ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT simulate
-    BUNDLE DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT simulate
-    PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR} COMPONENT simulate
-  )
-
-  if(NOT MUJOCO_SIMULATE_USE_SYSTEM_GLFW)
-    # We downloaded GLFW. Depending if it is a static or shared LIBRARY we might
-    # need to install it.
-    get_target_property(MJ_GLFW_LIBRARY_TYPE glfw TYPE)
-    if(MJ_GLFW_LIBRARY_TYPE STREQUAL SHARED_LIBRARY)
-      install(
-        TARGETS glfw
-        EXPORT ${PROJECT_NAME}
-        RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT simulate
-        LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT simulate
-        ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT simulate
-        PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR} COMPONENT simulate
+    macro(embed_in_bundle target)
+      add_dependencies(${target} simulate)
+      set_target_properties(
+        ${target}
+        PROPERTIES INSTALL_RPATH @executable_path/../Frameworks
+                   BUILD_WITH_INSTALL_RPATH TRUE
+                   RUNTIME_OUTPUT_DIRECTORY $<TARGET_FILE_DIR:simulate>
      )
+    endmacro()
+
+    # Embed mujoco.framework inside the App bundle ane move the icon file over too.
+    add_custom_command(
+      TARGET simulate
+      POST_BUILD
+      COMMAND mkdir -p $<TARGET_FILE_DIR:simulate>/../Frameworks
+      COMMAND rm -rf $<TARGET_FILE_DIR:simulate>/../Frameworks/mujoco.framework
+      COMMAND cp -a $<TARGET_FILE_DIR:mujoco::mujoco>/../../../mujoco.framework
+              $<TARGET_FILE_DIR:simulate>/../Frameworks/
+      # Delete the symlink and the TBD, otherwise we can't sign and notarize.
+      COMMAND rm -rf $<TARGET_FILE_DIR:simulate>/../Frameworks/mujoco.framework/mujoco.tbd
+      COMMAND rm -rf
+              $<TARGET_FILE_DIR:simulate>/../Frameworks/mujoco.framework/Versions/A/libmujoco.dylib
+    )
+  endif()
+
+  # Do not install if macOS Bundles are created as RPATH is managed manually there.
+  if(APPLE AND MUJOCO_BUILD_MACOS_FRAMEWORKS)
+    set(_INSTALL_SIMULATE OFF)
+  endif()
+
+  if(_INSTALL_SIMULATE)
+
+    include(TargetAddRpath)
+
+    # Add support to RPATH for the samples.
+    target_add_rpath(
+      TARGETS
+      simulate
+      INSTALL_DIRECTORY
+      "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}"
+      LIB_DIRS
+      "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}"
+      DEPENDS
+      MUJOCO_ENABLE_RPATH
+    )
+
+    install(
+      TARGETS simulate
+      EXPORT ${PROJECT_NAME}
+      RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT simulate
+      LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT simulate
+      ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT simulate
+      BUNDLE DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT simulate
+      PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR} COMPONENT simulate
+    )
+
+    if(NOT MUJOCO_SIMULATE_USE_SYSTEM_GLFW)
+      # We downloaded GLFW. Depending if it is a static or shared LIBRARY we might
+      # need to install it.
+      get_target_property(MJ_GLFW_LIBRARY_TYPE glfw TYPE)
+      if(MJ_GLFW_LIBRARY_TYPE STREQUAL SHARED_LIBRARY)
+        install(
+          TARGETS glfw
+          EXPORT ${PROJECT_NAME}
+          RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT simulate
+          LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT simulate
+          ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT simulate
+          PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR} COMPONENT simulate
+        )
+      endif()
    endif()
  endif()
 endif()
@@ -80,6 +80,7 @@ const struct Glfw& Glfw(void* dlhandle) {

    // go/keep-sorted start
    mjGLFW_INITIALIZE_SYMBOL(glfwCreateWindow);
+    mjGLFW_INITIALIZE_SYMBOL(glfwDestroyWindow);
    mjGLFW_INITIALIZE_SYMBOL(glfwGetCursorPos);
    mjGLFW_INITIALIZE_SYMBOL(glfwGetFramebufferSize);
    mjGLFW_INITIALIZE_SYMBOL(glfwGetKey);
@@ -115,10 +116,6 @@ const struct Glfw& Glfw(void* dlhandle) {

 #undef mjGLFW_INITIALIZE_SYMBOL

-#if defined(mjGLFW_DYNAMIC_SYMBOLS) && !defined(_MSC_VER)
-    dlclose(dlhandle);
-#endif
-
    return glfw;
  }();
  return glfw;
@@ -25,6 +25,7 @@ struct Glfw {
 #define mjGLFW_DECLARE_SYMBOL(func) decltype(&::func) func
  // go/keep-sorted start
  mjGLFW_DECLARE_SYMBOL(glfwCreateWindow);
+  mjGLFW_DECLARE_SYMBOL(glfwDestroyWindow);
  mjGLFW_DECLARE_SYMBOL(glfwGetCursorPos);
  mjGLFW_DECLARE_SYMBOL(glfwGetFramebufferSize);
  mjGLFW_DECLARE_SYMBOL(glfwGetKey);
@@ -337,7 +337,10 @@ void PhysicsLoop(mj::Simulate& sim) {
      mjData* dnew = nullptr;
      if (mnew) dnew = mj_makeData(mnew);
      if (dnew) {
-        sim.load(sim.dropfilename, mnew, dnew, true);
+        sim.load(sim.dropfilename, mnew, dnew);
+
+        mj_deleteData(d);
+        mj_deleteModel(m);

        m = mnew;
        d = dnew;
@@ -356,7 +359,10 @@ void PhysicsLoop(mj::Simulate& sim) {
      mjData* dnew = nullptr;
      if (mnew) dnew = mj_makeData(mnew);
      if (dnew) {
-        sim.load(sim.filename, mnew, dnew, true);
+        sim.load(sim.filename, mnew, dnew);
+
+        mj_deleteData(d);
+        mj_deleteModel(m);

        m = mnew;
        d = dnew;
@@ -482,7 +488,7 @@ void PhysicsThread(mj::Simulate* sim, const char* filename) {
    m = LoadModel(filename, *sim);
    if (m) d = mj_makeData(m);
    if (d) {
-      sim->load(filename, m, d, true);
+      sim->load(filename, m, d);
      mj_forward(m, d);

      // allocate ctrlnoise
@@ -1575,11 +1575,9 @@ void Simulate::applyforceperturbations() {
 //------------------------- Tell the render thread to load a file and wait -------------------------
 void Simulate::load(const char* file,
                    mjModel* mnew,
-                    mjData* dnew,
-                    bool delete_old_m_d) {
+                    mjData* dnew) {
  this->mnew = mnew;
  this->dnew = dnew;
-  this->delete_old_m_d = delete_old_m_d;
  mju::strcpy_arr(this->filename, file);

  {
@@ -1595,16 +1593,6 @@ void Simulate::load(const char* file,

 //------------------------------------- load mjb or xml model --------------------------------------
 void Simulate::loadmodel() {
-  if (this->delete_old_m_d) {
-    // delete old model if requested
-    if (this->d) {
-      mj_deleteData(d);
-    }
-    if (this->m) {
-      mj_deleteModel(m);
-    }
-  }
-
  this->m = this->mnew;
  this->d = this->dnew;

@@ -1618,7 +1606,8 @@ void Simulate::loadmodel() {
  this->pert.skinselect = -1;

  // align and scale view unless reloading the same file
-  if (mju::strcmp_arr(this->filename, this->previous_filename)) {
+  if (this->filename[0] &&
+      mju::strcmp_arr(this->filename, this->previous_filename)) {
    alignscale(this);
    mju::strcpy_arr(this->previous_filename, this->filename);
  }
@@ -1980,6 +1969,13 @@ void Simulate::renderloop() {
  this->clearcallback();
  mjv_freeScene(&this->scn);
  mjr_freeContext(&this->con);
+
+  Glfw().glfwDestroyWindow(this->window);
+}
+
+//------------------------------------ setup the glfw dispatch table -------------------------------
+void setglfwdlhandle(void* dlhandle) {
+  Glfw(dlhandle);
 }

 }  // namespace mujoco
@@ -54,7 +54,7 @@ class MJSIMULATEAPI Simulate {

  // Request that the Simulate UI thread render a new model
  // optionally delete the old model and data when done
-  void load(const char* file, mjModel* m, mjData* d, bool delete_old_m_d);
+  void load(const char* file, mjModel* m, mjData* d);

  // functions below are used by the renderthread
  // load mjb or xml model that has been requested by load()
@@ -79,7 +79,6 @@ class MJSIMULATEAPI Simulate {
  // model and data to be visualized
  mjModel* mnew = nullptr;
  mjData* dnew = nullptr;
-  bool delete_old_m_d = false;

  mjModel* m = nullptr;
  mjData* d = nullptr;
@@ -228,6 +227,10 @@ class MJSIMULATEAPI Simulate {
  char info_content[Simulate::kMaxFilenameLength] = {0};
 };

+// setup the glfw dispatch table
+// if set, must be called prior to other Simulate functions
+MJSIMULATEAPI void setglfwdlhandle(void* dlhandle);
+
 }  // namespace mujoco

 #endif