Expose support contact geometry helpers (#1552)

Summary:
Pull Request resolved: #1552

Exposes the shared Momentum support-contact and support-polygon helpers through `pymomentum.geometry`. The binding layer now only marshals NumPy skeleton/contact arrays while Momentum owns floor-locator, plane-collision, and convex-hull computations.

`support_polygon` now uses Momentum's positions-only support-contact helper so it does not build parent-index, parent-offset, or floor-position arrays when only hull inputs are needed. The binding also documents that skeleton-state conversion populates only world transforms for these geometry helpers and makes the default plane u-axis fallback robust when the normal is parallel to the preferred axis.

Reviewed By: cstollmeta

Differential Revision: D109891382

fbshipit-source-id: 22ebf00ab14393ffca397726d256a6e0b7c554f0

Author: yutingye

pymomentum/CMakeLists.txt

@@ -200,6 +200,7 @@ mt_python_binding(
   LINK_LIBRARIES
     array_utility
     character
+    character_solver
     io_character
     io_fbx
     io_file_save_options
@@ -209,6 +210,7 @@ mt_python_binding(
     io_shape
     io_skeleton
     io_urdf
+    math
     python_utility
 )
 

pymomentum/cmake/build_variables.bzl

@@ -154,6 +154,7 @@ geometry_public_headers = [
     "geometry/sdf_collider_pybind.h",
     "geometry/skeleton_pybind.h",
     "geometry/skin_weights_pybind.h",
+    "geometry/support_contacts_pybind.h",
     "geometry/texture_classification.h",
 ]
 
@@ -180,6 +181,7 @@ geometry_sources = [
     "geometry/sdf_collider_pybind.cpp",
     "geometry/skeleton_pybind.cpp",
     "geometry/skin_weights_pybind.cpp",
+    "geometry/support_contacts_pybind.cpp",
     "geometry/texture_classification.cpp",
 ]
 

pymomentum/geometry/geometry_pybind.cpp

@@ -25,6 +25,7 @@
 #include "pymomentum/geometry/sdf_collider_pybind.h"
 #include "pymomentum/geometry/skeleton_pybind.h"
 #include "pymomentum/geometry/skin_weights_pybind.h"
+#include "pymomentum/geometry/support_contacts_pybind.h"
 #include "pymomentum/geometry/texture_classification.h"
 #include "pymomentum/python_utility/eigen_quaternion.h"
 
@@ -1229,6 +1230,8 @@ Supports arbitrary leading dimensions with broadcasting and both float32/float64
       py::arg("character"),
       py::arg("joint_parameters"));
 
+  addSupportContactBindings(m);
+
   // jointParametersToLocalSkeletonState(character, jointParameters)
   m.def(
       "joint_parameters_to_local_skeleton_state",