Wave 3: dsp::xtc with X1–X6 gates; room~ harness-first phase (R1–R10 + FDN verdict)

include/ambitap/ambitap.h

@@ -20,6 +20,7 @@
 #include "dsp/spatial_compressor.h"
 #include "dsp/util/async_rebuilder.h"
 #include "dsp/virtual_mic.h"
+#include "dsp/xtc.h"
 #include "math/binaural/convolution.h"
 #include "math/binaural/hrtf_data.h"
 #include "math/binaural/ooura_fft.h"

notebooks/ambitap_py.py

@@ -71,6 +71,8 @@ def load() -> ctypes.CDLL:
             ctypes.c_int),
         "ambitap_builtin_hrtf_info": ([i32p, i32p, i32p, f32p], ctypes.c_int),
         "ambitap_builtin_hrtf_fir": ([ctypes.c_int, ctypes.c_int, ctypes.c_int, f32p], ctypes.c_int),
+        "ambitap_builtin_hrtf_hrir": (
+            [ctypes.c_int, ctypes.c_int, ctypes.c_float, ctypes.c_float, f32p, f32p], ctypes.c_int),
         "ambitap_resample_fir": (
             [f32p, ctypes.c_int, ctypes.c_float, ctypes.c_float, f32p, ctypes.c_int], ctypes.c_int),
         "ambitap_convolve": (
@@ -197,6 +199,21 @@ def builtin_hrtf(magls: bool = False) -> tuple[np.ndarray, np.ndarray]:
     return ears[0], ears[1]
 
 
+def builtin_hrtf_hrir(azimuth: float, elevation: float, *, order: int | None = None,
+                      magls: bool = False) -> tuple[np.ndarray, np.ndarray]:
+    """Time-domain SH-reconstructed KEMAR HRIR at a direction — the weighted
+    sum inside binaural_renderer::probe_response: (left, right), each
+    builtin length taps at the builtin sample rate."""
+    if order is None:
+        order = builtin_hrtf_info()["order"]
+    length = builtin_hrtf_info()["length"]
+    left = np.empty(length, dtype=np.float32)
+    right = np.empty(length, dtype=np.float32)
+    _check(_LIB.ambitap_builtin_hrtf_hrir(order, int(magls), float(azimuth), float(elevation),
+                                          _ptr(left), _ptr(right)), "builtin_hrtf_hrir")
+    return left, right
+
+
 def resample_fir(x: np.ndarray, in_rate: float, out_rate: float) -> np.ndarray:
     x = _f32(x)
     cap = int(np.ceil(len(x) * out_rate / in_rate)) + 8

tests/CMakeLists.txt

@@ -28,6 +28,7 @@ add_executable(ambitap_tests
     test_rt_safety.cpp
     test_embedded_core.cpp
     test_sofa.cpp
+    test_xtc.cpp
 )
 target_link_libraries(ambitap_tests PRIVATE
     AmbiTap::ambitap ambitap_warnings GTest::gtest_main)

tests/test_rt_safety.cpp

@@ -19,6 +19,7 @@
 #include "ambitap/dsp/rotator.h"
 #include "ambitap/dsp/spatial_compressor.h"
 #include "ambitap/dsp/virtual_mic.h"
+#include "ambitap/dsp/xtc.h"
 #include "ambitap/math/geometry/layouts.h"
 
 #include <gtest/gtest.h>
@@ -273,6 +274,23 @@ TEST(RtSafety, StatefulProcessorsAreAllocationFree) {
     EXPECT_EQ(guard.frees(), 0);
 }
 
+TEST(RtSafety, XtcProcessIsAllocationFree) {
+    constexpr size_t block = 64;
+
+    dsp::xtc x;
+    x.prepare(block, 48000.f);
+
+    std::vector<float> in_l(block, 0.25f), in_r(block, -0.25f);
+    std::vector<float> out_l(block), out_r(block);
+
+    rt_guard guard;
+    for (int i = 0; i < 8; ++i) {
+        x.process(in_l.data(), in_r.data(), out_l.data(), out_r.data(), block);
+    }
+    EXPECT_EQ(guard.allocations(), 0);
+    EXPECT_EQ(guard.frees(), 0);
+}
+
 TEST(RtSafety, BinauralRendererProcessIsAllocationFree) {
     constexpr size_t block = 64;