feat(rgbd): add RGB-D reconstruction pipeline

Add end-to-end RGB-D reconstruction support across the C++ core and Python API.

- add a native merge_rgbd_views path, view-aware 3D pose containers, and nanobind bindings

- expose Python helpers to sample aligned depth, apply per-joint offsets, lift UVD poses to world space, and run reconstruct_rgbd

- add RGB-D regression tests for merging, manual pipeline parity, symmetric depth sampling windows, and out-of-bounds joints

- bump the project version from 0.1.0 to 0.2.0 for the new feature surface

rpt/CMakeLists.txt

@@ -3,6 +3,7 @@
 set(RPT_SOURCES
     camera.cpp
     interface.cpp
+    rgbd_merger.cpp
     triangulator.cpp
 )
 

rpt/interface.cpp

@@ -23,6 +23,17 @@ size_t pose3d_offset(size_t person, size_t joint, size_t coord, size_t num_joint
 {
     return (((person * num_joints) + joint) * 4) + coord;
 }
+
+size_t pose3d_by_view_offset(
+    size_t view,
+    size_t person,
+    size_t joint,
+    size_t coord,
+    size_t max_persons,
+    size_t num_joints)
+{
+    return ((((view * max_persons) + person) * num_joints) + joint) * 4 + coord;
+}
 } // namespace
 
 // =================================================================================================
@@ -53,6 +64,11 @@ const float &TrackedPoseBatch3DView::at(size_t person, size_t joint, size_t coor
     return data[pose3d_offset(person, joint, coord, num_joints)];
 }
 
+const float &PoseBatch3DByViewView::at(size_t view, size_t person, size_t joint, size_t coord) const
+{
+    return data[pose3d_by_view_offset(view, person, joint, coord, max_persons, num_joints)];
+}
+
 const float &PoseBatch2D::at(size_t view, size_t person, size_t joint, size_t coord) const
 {
     return data[pose2d_offset(view, person, joint, coord, max_persons, num_joints)];
@@ -129,6 +145,27 @@ PoseBatch3DView PoseBatch3D::view() const
     return PoseBatch3DView {data.data(), num_persons, num_joints};
 }
 
+float &PoseBatch3DByView::at(size_t view, size_t person, size_t joint, size_t coord)
+{
+    return data[pose3d_by_view_offset(view, person, joint, coord, max_persons, num_joints)];
+}
+
+const float &PoseBatch3DByView::at(size_t view, size_t person, size_t joint, size_t coord) const
+{
+    return data[pose3d_by_view_offset(view, person, joint, coord, max_persons, num_joints)];
+}
+
+PoseBatch3DByViewView PoseBatch3DByView::view() const
+{
+    return PoseBatch3DByViewView {
+        data.data(),
+        person_counts.data(),
+        num_views,
+        max_persons,
+        num_joints,
+    };
+}
+
 NestedPoses3D PoseBatch3D::to_nested() const
 {
     NestedPoses3D poses_3d(num_persons);

rpt/interface.hpp

@@ -45,6 +45,17 @@ struct TrackedPoseBatch3DView
     const float &at(size_t person, size_t joint, size_t coord) const;
 };
 
+struct PoseBatch3DByViewView
+{
+    const float *data = nullptr;
+    const uint32_t *person_counts = nullptr;
+    size_t num_views = 0;
+    size_t max_persons = 0;
+    size_t num_joints = 0;
+
+    const float &at(size_t view, size_t person, size_t joint, size_t coord) const;
+};
+
 struct PoseBatch2D
 {
     std::vector<float> data;
@@ -74,6 +85,19 @@ struct PoseBatch3D
     static PoseBatch3D from_nested(const NestedPoses3D &poses_3d);
 };
 
+struct PoseBatch3DByView
+{
+    std::vector<float> data;
+    std::vector<uint32_t> person_counts;
+    size_t num_views = 0;
+    size_t max_persons = 0;
+    size_t num_joints = 0;
+
+    float &at(size_t view, size_t person, size_t joint, size_t coord);
+    const float &at(size_t view, size_t person, size_t joint, size_t coord) const;
+    PoseBatch3DByViewView view() const;
+};
+
 // =================================================================================================
 
 struct PairCandidate
@@ -242,6 +266,11 @@ PoseBatch3D triangulate_poses(
     const TriangulationConfig &config,
     const TriangulationOptions *options_override = nullptr);
 
+PoseBatch3D merge_rgbd_views(
+    const PoseBatch3DByViewView &poses_3d,
+    const TriangulationConfig &config,
+    float max_distance = 0.5f);
+
 TriangulationResult triangulate_with_report(
     const PoseBatch2DView &poses_2d,
     const TriangulationConfig &config,
@@ -256,6 +285,14 @@ inline PoseBatch3D triangulate_poses(
     return triangulate_poses(poses_2d.view(), config, options_override);
 }
 
+inline PoseBatch3D merge_rgbd_views(
+    const PoseBatch3DByView &poses_3d,
+    const TriangulationConfig &config,
+    float max_distance = 0.5f)
+{
+    return merge_rgbd_views(poses_3d.view(), config, max_distance);
+}
+
 inline TriangulationTrace triangulate_debug(
     const PoseBatch2D &poses_2d,
     const TriangulationConfig &config,