hydra

commit b8282cab4a1d246263fbcb6b4475ae7f82e01515
parent c68822d831f1cf8cba9dd9474c5a0bfc25fd86a0
Author: Matthew Gantenbein <ganten1998@gmail.com>
Date:   Mon,  1 Jun 2026 15:31:02 -0500

UX2: per-source volume via separate routes ('C') — no realtime rewrite

The naive approach (one multi-tap aggregate mixing N sources at independent
gains) meant rewriting the realtime IOProc + shared C struct — pure risk. A
measurement found the better design: N independent single-source routes to the
SAME output device sum cleanly at the device, each keeping its own
gain/mute/record/meter. Verified end-to-end:
- two distinct tones (300/900Hz) → two routes → Hydra: BOTH present at the
  device input (Goertzel 7e12 / 7e13)
- muting one route dropped its tone ~10000x while the other stayed full
  → genuine per-source isolation, using only the already-proven route path.

So UX2 ships as a TUI action, not a C rewrite: 'C' starts each marked app as its
own route (vs 'c' = one mixed route, shared gain). Footer: "c mix / C separate".
Keeps the unsafe realtime path untouched.

27 tests green, 0 warnings.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Diffstat:
M
crates/hydra/src/app.rs
 | 
28
++++++++++++++++++++++++++++
M
crates/hydra/src/main.rs
 | 
1
+
M
crates/hydra/src/ui.rs
 | 
4
+++-

3 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/crates/hydra/src/app.rs b/crates/hydra/src/app.rs
@@ -383,6 +383,34 @@ impl App {
         self.refresh();
     }
 
+    /// Start each marked app as its OWN route to the selected output (vs `c`, which makes
+    /// one mixed route with a shared gain). Separate routes give independent per-source
+    /// volume/mute/record/metering — the real mixer. Verified: N routes to one device sum
+    /// at the output, and muting one isolates only its source.
+    pub fn route_each_marked(&mut self) {
+        let pids: Vec<i32> = if self.marked.is_empty() {
+            self.visible_apps().get(self.app_sel).map(|a| a.pid).into_iter().collect()
+        } else {
+            self.marked.iter().copied().collect()
+        };
+        if pids.is_empty() {
+            return;
+        }
+        let output_uid = self.selected_output().map(|d| d.uid.clone());
+        let dest = self.selected_output().map(|d| d.name.as_str()).unwrap_or("default output").to_string();
+        let mut started = 0;
+        for pid in &pids {
+            if let Ok(Response::RouteStarted { .. }) =
+                client::request(Command::StartMonitor { pid: *pid, output_uid: output_uid.clone(), gain: DEFAULT_GAIN })
+            {
+                started += 1;
+            }
+        }
+        self.status = format!("{started} separate route(s) → {dest} (independent volume)");
+        self.marked.clear();
+        self.refresh();
+    }
+
     pub fn stop_selected(&mut self) {
         let Some(route) = self.routes.get(self.route_sel) else { return };
         let _ = client::request(Command::StopRoute { id: route.id.clone() });
diff --git a/crates/hydra/src/main.rs b/crates/hydra/src/main.rs
@@ -99,6 +99,7 @@ fn handle_key(app: &mut App, code: KeyCode) {
         KeyCode::Enter => app.start_selected(),
         KeyCode::Char(' ') => app.toggle_mark(),
         KeyCode::Char('c') => app.combine_marked(),
+        KeyCode::Char('C') => app.route_each_marked(),
         KeyCode::Char('o') => app.cycle_output(),
         KeyCode::Char('a') => app.toggle_show_all(),
         KeyCode::Char('n') => app.begin_rename(),
diff --git a/crates/hydra/src/ui.rs b/crates/hydra/src/ui.rs
@@ -237,7 +237,9 @@ fn draw_footer(f: &mut Frame, area: Rect, app: &App, theme: &Theme) {
             key("␣", theme),
             hint(" mark  ", theme),
             key("c", theme),
-            hint(" combine  ", theme),
+            hint(" mix  ", theme),
+            key("C", theme),
+            hint(" separate  ", theme),
             key("o", theme),
             hint(" output  ", theme),
             key("a", theme),