Define mj_multiRay bindings explicitly.

Fixes #1184.

PiperOrigin-RevId: 581956413
Change-Id: I6c611ac7537442a65e6961430ec724326ee6095a

python/mujoco/bindings_test.py

@@ -1135,6 +1135,41 @@ Euler integrator, semi-implicit in velocity.
         bodyexclude=0,
         geomid=geomid)
 
+  def test_mj_multi_ray(self):
+    nray = 3
+    geom1 = np.zeros(1, np.int32)
+    pnt = np.array([-0.3, 0, 0.1])
+    vec = np.array([[1, 0, 0], [0, 0, 1], [0, 0, -1]], np.float64)
+    dist_ex = np.array([0.2, -1, 0.1])
+    geom_ex = np.array([1, -1, 0])
+    geomid = np.zeros(nray, np.int32)
+    dist = np.zeros(nray, np.float64)
+
+    mujoco.mj_forward(self.model, self.data)
+    mujoco.mj_multiRay(
+        m=self.model,
+        d=self.data,
+        pnt=pnt,
+        vec=vec.flatten(),
+        geomgroup=None,
+        flg_static=1,
+        bodyexclude=-1,
+        geomid=geomid,
+        dist=dist,
+        nray=nray,
+        cutoff=mujoco.mjMAXVAL)
+
+    for i in range(0, 3):
+      self.assertEqual(
+          dist[i],
+          mujoco.mj_ray(
+              self.model, self.data, pnt, vec[i], None, 1, -1, geom1
+          ),
+      )
+      self.assertEqual(geomid[i], geom1)
+      self.assertEqual(geomid[i], geom_ex[i])
+      self.assertAlmostEqual(dist[i], dist_ex[i])
+
   def test_inverse_fd_none(self):
     eps = 1e-6
     flg_centered = 0

python/mujoco/functions.cc

@@ -24,6 +24,7 @@
 #include <Eigen/Core>
 #include <mujoco/mjxmacro.h>
 #include <mujoco/mujoco.h>
+#include "errors.h"
 #include "function_traits.h"
 #include "functions.h"
 #include "private.h"
@@ -38,6 +39,7 @@ PYBIND11_MODULE(_functions, pymodule) {
   namespace py = ::pybind11;
   namespace traits = python_traits;
 
+  using EigenVectorI = Eigen::Vector<int, Eigen::Dynamic>;
   using EigenVectorX = Eigen::Vector<mjtNum, Eigen::Dynamic>;
   using EigenArrayXX = Eigen::Array<
       mjtNum, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>;
@@ -568,7 +570,25 @@ PYBIND11_MODULE(_functions, pymodule) {
   Def<traits::mj_versionString>(pymodule);
 
   // Ray collision
-  Def<traits::mj_multiRay>(pymodule);
+  Def<traits::mj_multiRay>(
+      pymodule,
+      [](const raw::MjModel* m, raw::MjData* d, const mjtNum(*pnt)[3],
+         Eigen::Ref<const EigenVectorX> vec,
+         std::optional<Eigen::Ref<const Eigen::Vector<mjtByte, mjNGROUP>>>
+             geomgroup,
+         mjtByte flg_static, int bodyexclude, Eigen::Ref<EigenVectorI> geomid,
+         Eigen::Ref<EigenVectorX> dist, int nray, mjtNum cutoff) {
+        if (dist.size() != nray || geomid.size() != nray) {
+          throw py::type_error("dist and geomid should be of size nray");
+        }
+        if (vec.size() != 3 * nray) {
+          throw py::type_error("vec should be of size 3*nray");
+        }
+        InterceptMjErrors(::mj_multiRay)(
+            m, d, &(*pnt)[0], vec.data(),
+            geomgroup.has_value() ? geomgroup->data() : nullptr, flg_static,
+            bodyexclude, geomid.data(), dist.data(), nray, cutoff);
+      });
   Def<traits::mj_ray>(
       pymodule,
       [](const raw::MjModel* m, const raw::MjData* d, const mjtNum(*pnt)[3],