[nodes] Add a mono merger node

src/ossia/dataflow/nodes/merger.hpp

@@ -4,12 +4,60 @@
 
 namespace ossia::nodes
 {
+class mono_merger final : public ossia::graph_node
+{
+ int m_count{};
+
+public:
+ explicit mono_merger(int count)
+ : m_count{count}
+ {
+ for(int i = 0; i < count; i++)
+ {
+ auto inl = new ossia::audio_inlet;
+ inl->target<ossia::audio_port>()->set_channels(1);
+ m_inlets.push_back(std::move(inl));
+ }
+
+ m_outlets.push_back(new ossia::audio_outlet);
+ m_outlets.back()->target<ossia::audio_port>()->set_channels(count);
+ }
+
+ ~mono_merger() override = default;
+
+ void run(const ossia::token_request& t, ossia::exec_state_facade e) noexcept override
+ {
+ auto& op = *m_outlets.back()->target<ossia::audio_port>();
+ op.set_channels(this->m_count);
+ auto& out = op.get();
+ std::size_t cur = 0;
+ for(int i = 0; i < m_count; i++)
+ {
+ auto& in = m_inlets[i]->target<ossia::audio_port>()->get();
+
+ if(in.size() > 0)
+ out[cur++] = in[0];
+ else
+ out[cur++].resize(e.bufferSize());
+ }
+
+ for(auto& c : out)
+ {
+ if(c.size() < e.bufferSize())
+ {
+ c.resize(e.bufferSize());
+ }
+ }
+ }
+
+ [[nodiscard]] std::string label() const noexcept override { return "Mono Merger"; }
+};
 class merger final : public ossia::graph_node
 {
  int m_count{};
 
 public:
- merger(int count)
+ explicit merger(int count)
  : m_count{count}
  {
  for(int i = 0; i < count; i++)