Add density parameter to target APIs

Introduce a ray density parameter for targets: update the C++ bindings (includes/radarsimc.pxd) to add a density argument to AddTarget signatures (0.0 uses global density), and pass density from Python-side target dict (default 0.0) in cp_radarsimc.pyx and simulator_lidar.pyx. Also update the radarsimcpp submodule pointer to the new commit. This enables per-target ray density control while keeping skip_diffusion behavior unchanged.

Author: rookiepeng

src/radarsimcpp

@@ -140,7 +140,8 @@ cdef extern from "targets_manager.hpp":
                const vector[Vec3[T]] & rotation_rate_array,  # Time-varying rotation rates
                const cpp_complex[T] & ep,     # Relative permittivity (material property)
                const cpp_complex[T] & mu,     # Relative permeability (material property)
-               const bool & skip_diffusion) except +
+               const bool & skip_diffusion,   # Skip diffusion calculation flag
+               const T & density) except +    # Ray density (0.0 uses global density)
 
         void AddTargetSimple(const T * points,
                const int_t * cells,
@@ -150,7 +151,8 @@ cdef extern from "targets_manager.hpp":
                const Vec3[T] & speed,
                const Vec3[T] & rotation,
                const Vec3[T] & rotation_rate,
-               const bool & skip_diffusion) except +
+               const bool & skip_diffusion,   # Skip diffusion calculation flag
+               const T & density) except +    # Ray density (0.0 uses global density)
 
 #------------------------------------------------------------------------------
 # Ray Tracing Primitives

src/radarsimpy/includes/radarsimc.pxd

@@ -677,7 +677,8 @@ cdef void cp_AddTarget(radar,
                            rrt_vt,
                            ep_c,
                            mu_c,
-                           <bool> target.get("skip_diffusion", False))
+                           <bool> target.get("skip_diffusion", False),
+                           <float_t> target.get("density", 0.0))
 
 @cython.cdivision(True)
 @cython.boundscheck(False)
@@ -763,4 +764,5 @@ cdef void cp_RCS_Target(target, mesh_module, TargetsManager[float_t] * targets_m
                            rrt_vt,
                            ep_c,
                            mu_c,
-                           <bool> target.get("skip_diffusion", False))
+                           <bool> target.get("skip_diffusion", False),
+                           <float_t> target.get("density", 0.0))

src/radarsimpy/lib/cp_radarsimc.pyx

@@ -143,7 +143,8 @@ cpdef sim_lidar(lidar, targets, frame_time=0):
                                     Vec3[float_t](&speed_mv[0]),
                                     Vec3[float_t](&rotation_mv[0]),
                                     Vec3[float_t](&rotation_rate_mv[0]),
-                                    <bool> targets[idx_c].get("skip_diffusion", False))
+                                    <bool> targets[idx_c].get("skip_diffusion", False),
+                                    <float_t> targets[idx_c].get("density", 0.0))
 
     # Lidar parameters
     cdef float_t[:] phi_mv = np.radians(np.array(lidar["phi"], dtype=np_float))