Merge pull request #310 from orottier/feature/needless-clone

Prevent needless clone in offline rendering + in the online happy path

Author: orottier

src/render/graph.rs

@@ -354,7 +354,7 @@ impl Graph {
     }
 
     /// Render a single audio quantum by traversing the node list
-    pub fn render(&mut self, scope: &RenderScope) -> AudioRenderQuantum {
+    pub fn render(&mut self, scope: &RenderScope) -> &AudioRenderQuantum {
         // if the audio graph was changed, determine the new ordering
         if self.ordered.is_empty() {
             self.order_nodes();
@@ -460,12 +460,12 @@ impl Graph {
         }
 
         // Return the output buffer of destination node
-        self.nodes
+        &self
+            .nodes
             .get_mut(&AudioNodeId(0))
             .unwrap()
             .get_mut()
             .outputs[0]
-            .clone()
     }
 }
 

src/render/thread.rs

@@ -257,8 +257,8 @@ impl RenderThread {
                 node_id: Cell::new(AudioNodeId(0)), // placeholder value
             };
 
-            // render audio graph
-            let mut rendered = self.graph.as_mut().unwrap().render(&scope);
+            // render audio graph, clone it in case we need to mutate/store the value later
+            let mut rendered = self.graph.as_mut().unwrap().render(&scope).clone();
 
             // online AudioContext allows channel count to be less than no of hardware channels
             if rendered.number_of_channels() != self.number_of_channels {