Change mj_ray behaviour to match geom visualisation conventions:

- Planes and height-fields respect `mj_ray`'s `geom_group` argument.
- The `flg_static` argument now applies to all static geoms, not only those directly in the world body.

Before this change:
- Rays always intersected with height fields and planes, unless `flg_static` was set to 0.
- `flg_static` only applied to static geoms that were direct children of the world, but not geoms that were children of static bodies.

PiperOrigin-RevId: 534969091
Change-Id: I8dc7c320c63d6af95709b9f5e83a3c50e1c199fa

doc/changelog.rst

@@ -5,27 +5,29 @@ Changelog
 Upcoming version (not yet released)
 -----------------------------------
 
-.. youtube:: hqIMTNGaLF4
+.. youtube:: ZppeDArq6AU
    :align: right
    :width: 240px
 
+Models
+^^^^^^
+
+- Added `3x3x3 cube <https://github.com/deepmind/mujoco/blob/main/model/cube/cube_3x3x3.xml>`__ example model. See
+  `README <https://github.com/deepmind/mujoco/blob/main/model/cube/README.md>`__ for details.
 
 Bug fixes
-^^^^^^^
+^^^^^^^^^
 
 - Fixed a bug that was causing an incorrect computation of the mesh bounding box and coordinate frame if the volume was
-  invalid. In such case, now MuJoCo only accepts a non-watertight geometry if :ref:`shellinertia<body-geom-shellinertia>`
-  is equal to ``true``.
-
+  invalid. In such case, now MuJoCo only accepts a non-watertight geometry if
+  :ref:`shellinertia<body-geom-shellinertia>` is equal to ``true``.
 - Fixed the sparse Jacobian multiplication logic that is used to compute derivatives for tendon damping and fluid force,
   which affects the behaviour of the :ref:`implicit and implicitfast integrators<geIntegration>`.
+- Fixes to :ref:`mj_ray`, in line with geom visualisation conventions:
 
-Plugins
-^^^^^^^
-
-- Added touch-grid sensor plugin. See `documentation <https://github.com/deepmind/mujoco/blob/main/plugin/sensor/README.md>`_
-  for details, and associated `touch_grid.xml <https://github.com/deepmind/mujoco/blob/main/model/plugin/touch_grid.xml>`_
-  example model. The plugin includes `in-scene visualisation <https://youtu.be/0LOJ3WMnqeA>`_.
+  - Planes and height-fields respect the `geom_group` and `flg_static` arguments. Before this change, rays would
+    intersect planes and height-fields unconditionally.
+  - ``flg_static`` now apllies to all static geoms, not just those which are direct children of the world body.
 
 General
 ^^^^^^^
@@ -55,16 +57,17 @@ General
   model, within a range of width tausmooth.  See :ref:`Muscle actuators<CMuscle>` for more details.
   Relatedly, :ref:`mju_muscleDynamics` now takes 3 parameters instead of 2, adding the new smoothing-width parameter.
 
-
-.. youtube:: ZppeDArq6AU
+.. youtube:: hqIMTNGaLF4
    :align: right
    :width: 240px
 
-Models
-^^^^^^
+Plugins
+^^^^^^^
+
+- Added touch-grid sensor plugin. See `documentation <https://github.com/deepmind/mujoco/blob/main/plugin/sensor/README.md>`_
+  for details, and associated `touch_grid.xml <https://github.com/deepmind/mujoco/blob/main/model/plugin/touch_grid.xml>`_
+  example model. The plugin includes `in-scene visualisation <https://youtu.be/0LOJ3WMnqeA>`_.
 
-- Added `3x3x3 cube <https://github.com/deepmind/mujoco/blob/main/model/cube/cube_3x3x3.xml>`__ example model. See
-  `README <https://github.com/deepmind/mujoco/blob/main/model/cube/README.md>`__ for details.
 
 Version 2.3.5 (April 25, 2023)
 ------------------------------

src/engine/engine_ray.c

@@ -82,15 +82,10 @@ static int ray_eliminate(const mjModel* m, const mjData* d, int geomid,
   }
 
   // static exclusion
-  if (!flg_static && m->geom_bodyid[geomid]==0) {
+  if (!flg_static && m->body_weldid[m->geom_bodyid[geomid]]==0) {
     return 1;
   }
 
-  // plane and hfield inclusion
-  if (m->geom_type[geomid]==mjGEOM_PLANE || m->geom_type[geomid]==mjGEOM_HFIELD) {
-    return 0;
-  }
-
   // no geomgroup inclusion
   if (!geomgroup) {
     return 0;

test/engine/engine_ray_test.cc

@@ -39,10 +39,10 @@ static constexpr char kSingleGeomModel[] = R"(
 static constexpr char kRayCastingModel[] = R"(
 <mujoco>
   <worldbody>
-    <geom name="static_group1" type="sphere" size=".1" pos="1 0 0"
-     group="1"/>
+    <geom name="static_group1" type="sphere" size=".1" pos="1 0 0" group="1"/>
     <body pos="0 0 0">
       <body pos="0 0 0">
+        <joint/>
         <geom name="group0" type="sphere" size=".1" pos="3 0 0"/>
       </body>
       <geom name="group2" type="sphere" size=".1" pos="5 0 0" group="2"/>