Add mj_maxContact API function.

PiperOrigin-RevId: 903135055
Change-Id: I5f103c7d51f97e327c923bc567002ace835f5517

doc/APIreference/functions.rst

@@ -1179,6 +1179,18 @@ It is also triggered for :ref:`user sensors<sensor-user>` of :ref:`stage<sensor-
 The computed force arrays ``cfrc_int`` and ``cfrc_ext`` currently suffer from a know bug, they do not take into account
 the effect of spatial tendons, see :issue:`832`.
 
+.. _mj_maxContact:
+
+`mj_maxContact <#mj_maxContact>`__
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. mujoco-include:: mj_maxContact
+
+Return the maximum number of contacts that can be generated between two geoms.
+
+If has_margin is -1, then the margin is pulled from the model, otherwise if has_margin > 0
+indicates that the geoms have a positive margin.
+
 .. _mj_collision:
 
 `mj_collision <#mj_collision>`__

doc/changelog.rst

@@ -7,7 +7,8 @@ Upcoming version (not yet released)
 
 General
 ^^^^^^^
-
+- Added new :ref:`mj_maxContact<mj_maxContact>` function to get the maximum number of possible contacts returned by
+  two geoms.
 - Added :ref:`multi-cell support<body-flexcomp-cellnum>` for trilinear and quadratic flexes. Note that the implicit
   integrator uses a dense solver for the flex degrees of freedom, which can be slow for multi-cell flexes.
 - Refactored ``flexstrain`` equality constraints to be instantiated per cell instead of per flex object, reducing the

doc/computation/index.rst

@@ -1718,9 +1718,36 @@ work, but it pays off at runtime and yields both faster and more stable simulati
 Pair-wise colliders
 ^^^^^^^^^^^^^^^^^^^
 
-The table below provides information about the colliders used for different geom pairs. The second row in each cell
+The table below provides information about the colliders used for different geom pairs. These values can be computed
-lists the maximum number of contacts generated, possibly with ``multiccd`` enabled. For example, ``Mesh`` / ``Mesh``
+dynamically by the :ref:`mj_maxContact` function. Use the toggles to see the max number of contacts returned with the
-will generate up to 1 contact or with ``multiccd`` up to 4 contacts.
+parameters :ref:`nativeccd<option-flag-nativeccd>`, :ref:`multiccd<option-flag-multiccd>`, and
+:ref:`margin<body-geom-margin>`.
+
+.. raw:: html
+
+   <div class="pairwise-toggles">
+     <div class="pairwise-toggle-item">
+       <label class="pairwise-switch">
+         <input type="checkbox" id="nativeccd-checkbox" checked>
+         <span class="pairwise-slider"></span>
+       </label>
+       <span>nativeccd</span>
+     </div>
+     <div class="pairwise-toggle-item">
+       <label class="pairwise-switch">
+         <input type="checkbox" id="multiccd-checkbox">
+         <span class="pairwise-slider"></span>
+       </label>
+       <span>multiccd</span>
+     </div>
+     <div class="pairwise-toggle-item">
+       <label class="pairwise-switch">
+         <input type="checkbox" id="margin-checkbox">
+         <span class="pairwise-slider"></span>
+       </label>
+       <span>with margin</span>
+     </div>
+   </div>
 
 .. list-table::
    :header-rows: 1
@@ -1744,7 +1771,7 @@ will generate up to 1 contact or with ``multiccd`` up to 4 contacts.
      - | primitive
        | **1**
      - | primitive
-       | **2**
+       | **4**
      - | primitive
        | **4**
      - | primitive
@@ -1787,12 +1814,28 @@ will generate up to 1 contact or with ``multiccd`` up to 4 contacts.
        | **2**
      - | CCD
        | **1**
-     - | CCD
+     -
-       | **1**, **4**
+       .. raw:: html
+
+         <div class="line">CCD</div>
+         <div class="line">
+           <div class="multiccd-off"><strong>1</strong></div>
+           <div class="multiccd-native"><strong>5</strong></div>
+           <div class="multiccd-legacy"><strong>5</strong></div>
+         </div>
+
      - | primitive
        | **2**
-     - | CCD
+     -
-       | **1**, **4**
+       .. raw:: html
+
+         <div class="line">CCD</div>
+         <div class="line">
+           <div class="multiccd-off"><strong>1</strong></div>
+           <div class="multiccd-native"><strong>5</strong></div>
+           <div class="multiccd-legacy"><strong>5</strong></div>
+         </div>
+
      - | SDF
        | :ref:`sdf_initpoints <option-sdf_initpoints>`
    * - Ellipsoid
@@ -1812,12 +1855,36 @@ will generate up to 1 contact or with ``multiccd`` up to 4 contacts.
      -
      -
      -
-     - | CCD
+     -
-       | **1**, **4**
+       .. raw:: html
-     - | CCD
+
-       | **1**, **4**
+         <div class="line">CCD</div>
-     - | CCD
+         <div class="line">
-       | **1**, **4**
+           <div class="multiccd-off"><strong>1</strong></div>
+           <div class="multiccd-native"><strong>5</strong></div>
+           <div class="multiccd-legacy"><strong>5</strong></div>
+         </div>
+
+     -
+       .. raw:: html
+
+         <div class="line">CCD</div>
+         <div class="line">
+           <div class="multiccd-off"><strong>1</strong></div>
+           <div class="multiccd-native"><strong>5</strong></div>
+           <div class="multiccd-legacy"><strong>5</strong></div>
+         </div>
+
+     -
+       .. raw:: html
+
+         <div class="line">CCD</div>
+         <div class="line">
+           <div class="multiccd-off"><strong>1</strong></div>
+           <div class="multiccd-native"><strong>5</strong></div>
+           <div class="multiccd-legacy"><strong>5</strong></div>
+         </div>
+
      - | SDF
        | :ref:`sdf_initpoints <option-sdf_initpoints>`
    * - Box
@@ -1827,8 +1894,16 @@ will generate up to 1 contact or with ``multiccd`` up to 4 contacts.
      -
      - | primitive
        | **8**
-     - | CCD
+     -
-       | **1**, **4**
+       .. raw:: html
+
+         <div class="line">CCD</div>
+         <div class="line">
+           <div class="multiccd-off"><strong>1</strong></div>
+           <div class="multiccd-native"><strong>4</strong></div>
+           <div class="multiccd-legacy"><strong>5</strong></div>
+         </div>
+
      - | SDF
        | :ref:`sdf_initpoints <option-sdf_initpoints>`
    * - Mesh
@@ -1837,8 +1912,16 @@ will generate up to 1 contact or with ``multiccd`` up to 4 contacts.
      -
      -
      -
-     - | CCD
+     -
-       | **1**, **4**
+       .. raw:: html
+
+         <div class="line">CCD</div>
+         <div class="line">
+            <div class="multiccd-off"><strong>1</strong></div>
+            <div class="multiccd-native"><strong>4</strong></div>
+            <div class="multiccd-legacy"><strong>5</strong></div>
+         </div>
+
      - | MeshSDF
        | :ref:`sdf_initpoints <option-sdf_initpoints>`
    * - SDF
@@ -1851,6 +1934,32 @@ will generate up to 1 contact or with ``multiccd`` up to 4 contacts.
      - | SDF
        | :ref:`sdf_initpoints <option-sdf_initpoints>`
 
+.. raw:: html
+
+   <script>
+     const pairwiseToggles = () => {
+       const table = document.querySelector('.table-pairwise');
+       const toggles = [
+         {id: 'nativeccd-checkbox', cls: 'nativeccd-enabled'},
+         {id: 'multiccd-checkbox', cls: 'multiccd-enabled'},
+         {id: 'margin-checkbox', cls: 'margin-enabled'}
+       ];
+
+       toggles.forEach(toggle => {
+         const cb = document.getElementById(toggle.id);
+         if (cb.checked) {
+           table.classList.add(toggle.cls);
+         }
+         cb.addEventListener('change', () => {
+           table.classList.toggle(toggle.cls, this.checked);
+         });
+       });
+     };
+     pairwiseToggles();
+   </script>
+
+
+
 .. _Sleeping:
 
 Sleeping islands

doc/css/theme_overrides.css

@@ -54,6 +54,98 @@ body[data-theme="dark"] table.docutils:not(.mjcf-attributes) {
   font-size: 85%;
 }
 
+.pairwise-toggles {
+  display: flex;
+  align-items: center;
+  gap: 1.5em;
+  margin-bottom: 0.75em;
+}
+
+.pairwise-toggle-item {
+  display: flex;
+  align-items: center;
+  gap: 0.5em;
+}
+
+.pairwise-switch {
+  position: relative;
+  display: inline-block;
+  width: 36px;
+  height: 20px;
+}
+
+.pairwise-switch input {
+  opacity: 0;
+  width: 0;
+  height: 0;
+}
+
+.pairwise-slider {
+  position: absolute;
+  cursor: pointer;
+  inset: 0;
+  background-color: #ccc;
+  transition: 0.3s;
+  border-radius: 20px;
+}
+
+.pairwise-slider:before {
+  content: "";
+  position: absolute;
+  height: 14px;
+  width: 14px;
+  left: 3px;
+  bottom: 3px;
+  background-color: white;
+  transition: 0.3s;
+  border-radius: 50%;
+}
+
+.pairwise-switch input:checked + .pairwise-slider {
+  background-color: var(--secondary-header-color, #123693);
+}
+
+.pairwise-switch input:checked + .pairwise-slider:before {
+  transform: translateX(16px);
+}
+
+.multiccd-off,
+.multiccd-native,
+.multiccd-legacy {
+  display: none;
+  margin: 0;
+}
+
+.multiccd-off {
+  display: inline;
+}
+
+.multiccd-enabled .multiccd-off {
+  display: none;
+}
+
+.multiccd-enabled.nativeccd-enabled:not(.margin-enabled) .multiccd-native {
+  display: inline;
+}
+
+.multiccd-enabled:not(.nativeccd-enabled) .multiccd-legacy,
+.multiccd-enabled.nativeccd-enabled.margin-enabled .multiccd-legacy {
+  display: inline;
+}
+
+.margin-show {
+  display: none;
+}
+
+.margin-enabled .margin-hide {
+  display: none;
+}
+
+.margin-enabled .margin-show {
+  display: inline;
+}
+
+
 .small-centered td, .small-centered th,
 .table-pairwise td, .table-pairwise th {
   text-align: center !important;

doc/includes/references.h

@@ -3272,6 +3272,7 @@ void mj_passive(const mjModel* m, mjData* d);
 void mj_subtreeVel(const mjModel* m, mjData* d);
 void mj_rne(const mjModel* m, mjData* d, int flg_acc, mjtNum* result);
 void mj_rnePostConstraint(const mjModel* m, mjData* d);
+int mj_maxContact(const mjModel* m, int g1, int g2, int has_margin);
 void mj_collision(const mjModel* m, mjData* d);
 void mj_makeConstraint(const mjModel* m, mjData* d);
 void mj_island(const mjModel* m, mjData* d);

include/mujoco/mujoco.h

@@ -460,6 +460,11 @@ MJAPI void mj_rne(const mjModel* m, mjData* d, int flg_acc, mjtNum* result);
 // RNE with complete data: compute cacc, cfrc_ext, cfrc_int.
 MJAPI void mj_rnePostConstraint(const mjModel* m, mjData* d);
 
+// Return the maximum number of contacts that can be generated between two geoms.
+// If has_margin is -1, then the margin is pulled from the model, otherwise if has_margin > 0
+// indicates that the geoms have a positive margin.
+MJAPI int mj_maxContact(const mjModel* m, int g1, int g2, int has_margin);
+
 // Run collision detection.
 MJAPI void mj_collision(const mjModel* m, mjData* d);
 

python/mujoco/functions.cc

@@ -304,6 +304,7 @@ PYBIND11_MODULE(_functions, pymodule) {
             m, d, flg_acc, result.data());
       });
   Def<traits::mj_rnePostConstraint>(pymodule);
+  Def<traits::mj_maxContact>(pymodule);
   Def<traits::mj_collision>(pymodule);
   Def<traits::mj_makeConstraint>(pymodule);
   Def<traits::mj_island>(pymodule);

python/mujoco/introspect/functions.py

@@ -2407,6 +2407,32 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
          ),
          doc='RNE with complete data: compute cacc, cfrc_ext, cfrc_int.',
      )),
+    ('mj_maxContact',
+     FunctionDecl(
+         name='mj_maxContact',
+         return_type=ValueType(name='int'),
+         parameters=(
+             FunctionParameterDecl(
+                 name='m',
+                 type=PointerType(
+                     inner_type=ValueType(name='mjModel', is_const=True),
+                 ),
+             ),
+             FunctionParameterDecl(
+                 name='g1',
+                 type=ValueType(name='int'),
+             ),
+             FunctionParameterDecl(
+                 name='g2',
+                 type=ValueType(name='int'),
+             ),
+             FunctionParameterDecl(
+                 name='has_margin',
+                 type=ValueType(name='int'),
+             ),
+         ),
+         doc='Return the maximum number of contacts that can be generated between two geoms. If has_margin is -1, then the margin is pulled from the model, otherwise if has_margin > 0 indicates that the geoms have a positive margin.',  # pylint: disable=line-too-long
+     )),
     ('mj_collision',
      FunctionDecl(
          name='mj_collision',

src/engine/engine_collision_driver.c

@@ -38,7 +38,7 @@
 #include "engine/engine_util_spatial.h"
 
 
-// table of pair-wise collision functions
+// table of pairwise collision functions
 mjfCollision mjCOLLISIONFUNC[mjNGEOMTYPES][mjNGEOMTYPES] = {
   /*              PLANE  HFIELD  SPHERE            CAPSULE             ELLIPSOID         CYLINDER            BOX               MESH              SDF */
   /*PLANE     */ {0,     0,      mjc_PlaneSphere,  mjc_PlaneCapsule,   mjc_PlaneConvex,  mjc_PlaneCylinder,  mjc_PlaneBox,     mjc_PlaneConvex,  mjc_PlaneConvex},
@@ -56,6 +56,104 @@ mjfCollision mjCOLLISIONFUNC[mjNGEOMTYPES][mjNGEOMTYPES] = {
 
 //------------------------------------ utility functions ------------------------------------------
 
+
+// return the maximum number of contacts that can be generated between two geoms
+// if has_margin is -1, then the margin is pulled from the model, otherwise if has_margin > 0
+// indicates that the geoms have a positive margin
+int mj_maxContact(const mjModel* m, int g1, int g2, int has_margin) {
+  int type1 = m->geom_type[g1];
+  int type2 = m->geom_type[g2];
+
+  if (type1 == mjGEOM_SDF || type2 == mjGEOM_SDF) {
+    return m->opt.sdf_initpoints;
+  }
+
+  if (type1 == mjGEOM_HFIELD || type2 == mjGEOM_HFIELD) {
+    int type = (type1 == mjGEOM_HFIELD) ? type2 : type1;
+    return (type != mjGEOM_PLANE && type != mjGEOM_HFIELD) ? mjMAXCONPAIR : 0;
+  }
+
+  // spheres and ellipsoids always generate a single contact
+  if (type1 == mjGEOM_SPHERE || type1 == mjGEOM_ELLIPSOID ||
+      type2 == mjGEOM_SPHERE || type2 == mjGEOM_ELLIPSOID) {
+    return 1;
+  }
+
+  // box-box primitive collider
+  if (type1 == mjGEOM_BOX && type2 == mjGEOM_BOX) {
+    return 8;
+  }
+
+  // capsule-capsule primitive collider
+  if (type1 == mjGEOM_CAPSULE && type2 == mjGEOM_CAPSULE) {
+    return 2;
+  }
+
+  // capsule-box primitive collider
+  if ((type1 == mjGEOM_CAPSULE && type2 == mjGEOM_BOX) ||
+      (type1 == mjGEOM_BOX && type2 == mjGEOM_CAPSULE)) {
+    return 4;
+  }
+
+  // the remaining plane cases
+  if (type1 == mjGEOM_PLANE || type2 == mjGEOM_PLANE) {
+    int type = (type1 == mjGEOM_PLANE) ? type2 : type1;
+    switch (type) {
+      case mjGEOM_CAPSULE:
+        return 2;
+      case mjGEOM_CYLINDER:
+      case mjGEOM_BOX:
+        return 4;
+      case mjGEOM_MESH:
+        return 3;
+      default:
+        return 0;
+    }
+  }
+
+  int is_multiccd = !mjDISABLED(mjDSBL_MULTICCD);
+  if (!is_multiccd) {
+    return 1;
+  }
+
+  if (type1 == mjGEOM_CAPSULE || type2 == mjGEOM_CAPSULE ||
+      type1 == mjGEOM_CYLINDER || type2 == mjGEOM_CYLINDER) {
+    return 5;
+  }
+
+  if (mjDISABLED(mjDSBL_NATIVECCD)) {
+    return is_multiccd ? 5 : 1;  // mesh-mesh or mesh-box with libccd
+  }
+
+  // check margin from model
+  if (has_margin < 0) {
+    has_margin = 0;
+    if (mjENABLED(mjENBL_OVERRIDE)) {
+      has_margin = m->opt.o_margin > 0.0;
+    } else {
+      int npair = m->npair;
+      int ipair = -1;
+      for (int k=0; k < npair; k++) {
+        if ((m->pair_geom1[k] == g1 && m->pair_geom2[k] == g2) ||
+            (m->pair_geom1[k] == g2 && m->pair_geom2[k] == g1)) {
+            ipair = k;
+            break;
+          }
+        }
+
+      if (ipair > -1) {
+        has_margin = m->pair_margin[ipair] > 0.0;
+      } else {
+        has_margin = m->geom_margin[g1] > 0.0 || m->geom_margin[g2] > 0.0;
+      }
+    }
+  }
+
+  // 4 contacts for mesh-mesh or mesh-box without margins, 5 with margins
+  return has_margin ? 5 : 4;
+}
+
+
 // move arena pointer back to the end of the contact array
 static inline void resetArena(mjData* d) {
   d->parena = d->ncon * sizeof(mjContact);

src/engine/engine_collision_driver.h

@@ -18,6 +18,7 @@
 #include <mujoco/mjdata.h>
 #include <mujoco/mjexport.h>
 #include <mujoco/mjmodel.h>
+#include <mujoco/mjtnum.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -26,10 +27,15 @@ extern "C" {
 // collision function pointers and max contact pairs
 MJAPI extern mjfCollision mjCOLLISIONFUNC[mjNGEOMTYPES][mjNGEOMTYPES];
 
+// return the maximum number of contacts that can be generated between two geoms
+// if has_margin is -1, then the margin is pulled from the model, otherwise if has_margin > 0
+// indicates that the geoms have a positive margin
+MJAPI int mj_maxContact(const mjModel* m, int g1, int g2, int has_margin);
+
 // collision detection entry point
 MJAPI void mj_collision(const mjModel* m, mjData* d);
 
-// applies Separating Axis Theorem for rotated AABBs
+// apply the Separating Axis Theorem for rotated AABBs
 MJAPI int mj_collideOBB(const mjtNum aabb1[6], const mjtNum aabb2[6],
                         const mjtNum xpos1[3], const mjtNum xmat1[9],
                         const mjtNum xpos2[3], const mjtNum xmat2[9], mjtNum margin,

test/engine/engine_collision_driver_test.cc

@@ -390,5 +390,73 @@ TEST_F(MjCollisionTest, MarginSumming) {
   mj_deleteModel(m);
 }
 
+TEST_F(MjCollisionTest, MaxContact) {
+  constexpr char xml[] = R"(
+  <mujoco>
+    <option>
+      <flag multiccd="enable"/>
+    </option>
+    <asset>
+      <mesh name="smallbox"
+        vertex="-1 -1 -1  1 -1 -1   1  1 -1
+                 1  1  1  1 -1  1  -1  1 -1
+                -1  1  1 -1 -1  1"/>
+    </asset>
+    <worldbody>
+      <geom name="mesh" type="mesh" mesh="smallbox"/>
+      <geom name="box" type="box" size="1 1 1"/>
+      <geom name="plane" type="plane" size="1 1 1"/>
+      <geom name="sphere" type="sphere" size="1"/>
+      <geom name="capsule" type="capsule" size="1 1"/>
+      <geom name="ellipsoid" type="ellipsoid" size="1 1 1"/>
+      <geom name="cylinder" type="cylinder" size="1 1"/>
+    </worldbody>
+  </mujoco>
+  )";
+  char error[1024];
+  mjModel* m = LoadModelFromString(xml, error, sizeof(error));
+  ASSERT_THAT(m, NotNull()) << error;
+  mjData* d = mj_makeData(m);
+  ASSERT_THAT(d, NotNull());
+
+  int mesh = mj_name2id(m, mjOBJ_GEOM, "mesh");
+  int box = mj_name2id(m, mjOBJ_GEOM, "box");
+  int plane = mj_name2id(m, mjOBJ_GEOM, "plane");
+  int sphere = mj_name2id(m, mjOBJ_GEOM, "sphere");
+  int capsule = mj_name2id(m, mjOBJ_GEOM, "capsule");
+  int ellipsoid = mj_name2id(m, mjOBJ_GEOM, "ellipsoid");
+  int cylinder = mj_name2id(m, mjOBJ_GEOM, "cylinder");
+
+  EXPECT_EQ(mj_maxContact(m, mesh, box, -1), 4);
+  EXPECT_EQ(mj_maxContact(m, mesh, plane, -1), 3);
+  EXPECT_EQ(mj_maxContact(m, box, plane, -1), 4);
+  EXPECT_EQ(mj_maxContact(m, mesh, mesh, -1), 4);
+  EXPECT_EQ(mj_maxContact(m, box, box, -1), 8);
+  EXPECT_EQ(mj_maxContact(m, capsule, capsule, -1), 2);
+  EXPECT_EQ(mj_maxContact(m, capsule, box, -1), 4);
+  EXPECT_EQ(mj_maxContact(m, capsule, plane, -1), 2);
+  EXPECT_EQ(mj_maxContact(m, cylinder, plane, -1), 4);
+  EXPECT_EQ(mj_maxContact(m, sphere, sphere, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, sphere, capsule, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, sphere, box, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, sphere, mesh, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, sphere, plane, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, sphere, cylinder, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, ellipsoid, ellipsoid, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, ellipsoid, box, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, ellipsoid, mesh, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, ellipsoid, plane, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, ellipsoid, cylinder, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, ellipsoid, capsule, -1), 1);
+  EXPECT_EQ(mj_maxContact(m, capsule, cylinder, -1), 5);
+  EXPECT_EQ(mj_maxContact(m, capsule, mesh, -1), 5);
+  EXPECT_EQ(mj_maxContact(m, cylinder, cylinder, -1), 5);
+  EXPECT_EQ(mj_maxContact(m, cylinder, box, -1), 5);
+  EXPECT_EQ(mj_maxContact(m, cylinder, mesh, -1), 5);
+
+  mj_deleteData(d);
+  mj_deleteModel(m);
+}
+
 }  // namespace
 }  // namespace mujoco

unity/Runtime/Bindings/MjBindings.cs

@@ -6951,6 +6951,9 @@ public static unsafe extern void mj_rne(mjModel_* m, mjData_* d, int flg_acc, do
 [DllImport("mujoco", CallingConvention = CallingConvention.Cdecl)]
 public static unsafe extern void mj_rnePostConstraint(mjModel_* m, mjData_* d);
 
+[DllImport("mujoco", CallingConvention = CallingConvention.Cdecl)]
+public static unsafe extern int mj_maxContact(mjModel_* m, int g1, int g2, int has_margin);
+
 [DllImport("mujoco", CallingConvention = CallingConvention.Cdecl)]
 public static unsafe extern void mj_collision(mjModel_* m, mjData_* d);
 

wasm/codegen/generated/bindings.cc

@@ -8845,6 +8845,10 @@ void mj_makeM_wrapper(const MjModel& m, MjData& d) {
   mj_makeM(m.get(), d.get());
 }
 
+int mj_maxContact_wrapper(const MjModel& m, int g1, int g2, int has_margin) {
+  return mj_maxContact(m.get(), g1, g2, has_margin);
+}
+
 void mj_mulJacTVec_wrapper(const MjModel& m, const MjData& d, const val& res, const NumberArray& vec) {
   UNPACK_VALUE(mjtNum, res);
   UNPACK_ARRAY(mjtNum, vec);
@@ -13173,6 +13177,7 @@ EMSCRIPTEN_BINDINGS(mujoco_bindings) {
   function("mj_local2Global", &mj_local2Global_wrapper);
   function("mj_makeConstraint", &mj_makeConstraint_wrapper);
   function("mj_makeM", &mj_makeM_wrapper);
+  function("mj_maxContact", &mj_maxContact_wrapper);
   function("mj_mulJacTVec", &mj_mulJacTVec_wrapper);
   function("mj_mulJacVec", &mj_mulJacVec_wrapper);
   function("mj_mulM", &mj_mulM_wrapper);