fixes issue when there are no visible sources

CHANGELOG.rst

@@ -24,6 +24,8 @@ Bugfix
 - Fixes a bug in ``beamforming.circular_microphone_array_xyplane`` (#348)
 - Fixes a bug in ``room.Room.plot_rir`` where the x-axis would have the wrong
   ticks when called with ``kind="tf"``
+- Fixes an issue where the ``visibility`` attribute of the room is not
+  set if there are no visible source or image source in the room. (#313)
 
 `0.7.4`_ - 2024-04-25
 ---------------------

pyroomacoustics/room.py

@@ -2149,9 +2149,9 @@ def image_source_model(self):
         self.visibility = []
 
         for source in self.sources:
-            n_sources = self.room_engine.image_source_model(source.position)
+            n_visible_sources = self.room_engine.image_source_model(source.position)
 
-            if n_sources > 0:
+            if n_visible_sources > 0:
                 # Copy to python managed memory
                 source.images = self.room_engine.sources.copy()
                 source.orders = self.room_engine.orders.copy()
@@ -2181,6 +2181,10 @@ def image_source_model(self):
                     # if not, it's not visible from anywhere!
                     if not self.is_inside(self.mic_array.R[:, m]):
                         self.visibility[-1][m, :] = 0
+            else:
+                # if we are here, this means even the direct path is not visible
+                # we set the visibility of the direct path as 0
+                self.visibility.append(np.zeros((self.mic_array.M, 1)))
 
         # Update the state
         self.simulator_state["ism_done"] = True
@@ -2315,9 +2319,6 @@ def compute_rir(self):
                                 degrees=False,
                             )
 
-                        # Use the Cython extension for the fractional delays
-                        # from .build_rir import fast_rir_builder
-
                         vis = self.visibility[s][m, :].astype(np.int32)
                         # we add the delay due to the factional delay filter to
                         # the arrival times to avoid problems when propagation

pyroomacoustics/tests/test_issue_313.py

@@ -0,0 +1,50 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+import pyroomacoustics as pra
+
+
+def test_issue_313():
+    """
+    Fixes an issue where the `visibility` attribute of the room is not
+    set if there are no visible source or image source in the room.
+    """
+    # Room
+    sigma2 = 5e-4
+    fs = 16000
+
+    corners = np.array(
+        [
+            [0, 0],
+            [10, 0],
+            [10, 16],
+            [0, 16],
+            [0, 10],
+            [8, 10],
+            [8, 6],
+            [0, 6],
+        ]
+    ).T
+    room = pra.Room.from_corners(corners, fs=fs, max_order=1, sigma2_awgn=sigma2)
+
+    # Microphones
+    def mic_array_at(pos: np.ndarray) -> pra.MicrophoneArray:
+        mic_locations = pra.circular_2D_array(center=pos, M=6, phi0=0, radius=37.5e-3)
+        mic_locations = np.concatenate(
+            (mic_locations, np.array(pos, ndmin=2).T), axis=1
+        )
+        return pra.MicrophoneArray(mic_locations, room.fs)
+
+    mic = mic_array_at(np.array([3, 3]))
+    room.add_microphone_array(mic)
+
+    # Sources
+    rng = np.random.RandomState(23)
+    duration_samples = int(fs)
+    source_location = np.array([3, 13])
+    source_signal = rng.randn(duration_samples)
+    room.add_source(source_location, signal=source_signal)
+
+    room.image_source_model()
+
+    room.compute_rir()