[audio] Add two simple utility objects

examples/Advanced/Utilities/AudioSum.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+
+#include <halp/audio.hpp>
+#include <halp/controls.hpp>
+#include <halp/meta.hpp>
+#include <halp/soundfile_port.hpp>
+
+namespace ao
+{
+class AudioSum
+{
+public:
+  halp_meta(name, "Audio Sum")
+  halp_meta(c_name, "audio_sum")
+  halp_meta(category, "Audio")
+  halp_meta(author, "Jean-Michaël Celerier")
+  halp_meta(description, "Sum all the input channels")
+  halp_meta(uuid, "8938ca07-ce26-4d0a-b7f9-bff465a28a97")
+
+  struct
+  {
+    halp::dynamic_audio_bus<"Input", double> audio;
+  } inputs;
+
+  struct
+  {
+    halp::fixed_audio_bus<"Output", double, 1> audio;
+  } outputs;
+
+  void operator()(int frames)
+  {
+    auto out = outputs.audio.channel(0, frames);
+    for(int j = 0; j < frames; j++)
+      out[j] = 0.;
+
+    for(int i = 0; i < inputs.audio.channels; i++)
+    {
+      const auto in = inputs.audio.channel(i, frames);
+      for(int j = 0; j < frames; j++)
+        out[j] += in[j];
+    }
+  }
+};
+}

examples/Advanced/Utilities/Silence.hpp

@@ -0,0 +1,44 @@
+#pragma once
+
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+
+#include <halp/audio.hpp>
+#include <halp/controls.hpp>
+#include <halp/meta.hpp>
+#include <halp/soundfile_port.hpp>
+
+namespace ao
+{
+class Silence
+{
+public:
+  halp_meta(name, "Silence")
+  halp_meta(c_name, "silence")
+  halp_meta(category, "Audio")
+  halp_meta(author, "Jean-Michaël Celerier")
+  halp_meta(description, "Enjoy the silence")
+  halp_meta(uuid, "3bf48e32-06c0-4693-8a80-062ae9b5eac8")
+
+  struct
+  {
+    halp::spinbox_i32<"Channels"> channels;
+  } inputs;
+
+  struct
+  {
+    halp::variable_audio_bus<"Output", double> audio;
+  } outputs;
+
+  using setup = halp::setup;
+  void prepare(halp::setup s) { outputs.audio.request_channels(inputs.channels); }
+
+  void operator()()
+  {
+    if(outputs.audio.channels != inputs.channels)
+    {
+      outputs.audio.request_channels(inputs.channels);
+      return;
+    }
+  }
+};
+}