Implement joint equality constraint. Streamline constraint functions.

PiperOrigin-RevId: 577905570
Change-Id: I70580d21e3c612606b967cdd84ad22794c672397

doc/changelog.rst

@@ -13,29 +13,30 @@ General
 
 MJX
 ^^^
-2. Fixed bug where mixed ``jnt_limited`` joints were not being constrained correctly.
-3. Made ``device_put`` type validation more verbose (fixes :github:issue:`1113`).
-4. Removed empty EFC rows from `MJX`, for joints with no limits (fixes :github:issue:`1117`).
+2. Added support for joint equality constraints (``mjEQ_JOINT`` in :ref:`mjtEq`).
+3. Fixed bug where mixed ``jnt_limited`` joints were not being constrained correctly.
+4. Made ``device_put`` type validation more verbose (fixes :github:issue:`1113`).
+5. Removed empty EFC rows from `MJX`, for joints with no limits (fixes :github:issue:`1117`).
 
 Python bindings
 ^^^^^^^^^^^^^^^
 
-5. Fix the macOS ``mjpython`` launcher to work with the Python interpreter from Apple Command Line
+6. Fix the macOS ``mjpython`` launcher to work with the Python interpreter from Apple Command Line
    Tools.
 
 Simulate
 ^^^^^^^^
-6. :ref:`simulate<saSimulate>`: correct handling of "Pause update", "Fullscreen" and "VSync" buttons.
+7. :ref:`simulate<saSimulate>`: correct handling of "Pause update", "Fullscreen" and "VSync" buttons.
 
 Documentation
 ^^^^^^^^^^^^^
-7. Added documentation for the :ref:`UI` framework.
-8. Fixed typos and supported fields in docs (fixes :github:issue:`1105` and :github:issue:`1106`).
+8. Added documentation for the :ref:`UI` framework.
+9. Fixed typos and supported fields in docs (fixes :github:issue:`1105` and :github:issue:`1106`).
 
 
 Bug fixes
 ^^^^^^^^^
-9. Fixed bug relating to welds modified with :ref:`torquescale<equality-weld-torquescale>`.
+10. Fixed bug relating to welds modified with :ref:`torquescale<equality-weld-torquescale>`.
 
 Version 3.0.0 (October 18, 2023)
 --------------------------------

doc/mjx.rst

@@ -188,9 +188,9 @@ The following features are **fully supported** in MJX:
    * - :ref:`Geom <mjtGeom>`
      - ``PLANE``, ``SPHERE``, ``CAPSULE``, ``BOX``, ``MESH``
    * - :ref:`Constraint <mjtConstraint>`
-     - ``EQUALITY``, ``FRICTION_DOF``, ``LIMIT_JOINT``, ``CONTACT_PYRAMIDAL``
+     - ``EQUALITY``, ``LIMIT_JOINT``, ``CONTACT_PYRAMIDAL``
    * - :ref:`Equality <mjtEq>`
-     - ``CONNECT``, ``WELD``
+     - ``CONNECT``, ``WELD``, ``JOINT``
    * - :ref:`Integrator <mjtIntegrator>`
      - ``EULER``, ``RK4``
    * - :ref:`Cone <mjtCone>`
@@ -218,6 +218,8 @@ The following features are **in development** and coming soon:
      - ``TRN_TENDON``
    * - :ref:`Geom <mjtGeom>`
      - ``HFIELD``, ``ELLIPSOID``, ``CYLINDER``, ``SDF``
+   * - :ref:`Constraint <mjtConstraint>`
+     - ``CONTACT_FRICTIONLESS``, ``CONTACT_ELLIPTIC``, ``FRICTION_DOF``
    * - :ref:`Integrator <mjtIntegrator>`
      - ``IMPLICIT``, ``IMPLICITFAST``
    * - :ref:`Cone <mjtCone>`
@@ -231,7 +233,7 @@ The following features are **in development** and coming soon:
    * - :ref:`Tendons <tendon>`
      - :ref:`Spatial <tendon-spatial>`, :ref:`Fixed <tendon-fixed>`
    * - :ref:`Equality <mjtEq>`
-     - ``JOINT``, ``TENDON``
+     - ``TENDON``
    * - :ref:`Sensors <mjtSensor>`
      - All except ``mjSENS_PLUGIN``, ``mjSENS_USER``