Web: add panning, move mixing to wasm

web/VB.js

@@ -285,6 +285,7 @@ class Sim extends HTMLElement {
     #core;      // Core proxy
     #emulating; // Current emulation status
     #keys;      // Controller state
+    #panning;   // Audio stereo balance
     #peer;      // Communication peer
     #pointer;   // Pointer in core memory
     #volume;    // Audio output volume
@@ -313,9 +314,10 @@ class Sim extends HTMLElement {
         this.#core      = core;
         this.#emulating = false;
         this.#keys      = Constants.VB.SGN;
+        this.#panning   = 0.0;
         this.#peer      = null;
         this.#pointer   = pointer;
-        this.#volume    = 1;
+        this.#volume    = 1.0;
         delete this.proxy;
 
         // Create a <canvas> for the video image
@@ -358,10 +360,11 @@ class Sim extends HTMLElement {
     /////////////////////////// Property Accessors ////////////////////////////
 
     get anaglyph() { return this.#anaglyph.slice(); }
-    get core    () { return this.#core.core; }
-    get keys    () { return this.#keys; }
-    get peer    () { return this.#peer; }
-    get volume  () { return this.#volume; }
+    get core    () { return this.#core.core       ; }
+    get keys    () { return this.#keys            ; }
+    get panning () { return this.#panning         ; }
+    get peer    () { return this.#peer            ; }
+    get volume  () { return this.#volume          ; }
 
 
 
@@ -479,6 +482,27 @@ class Sim extends HTMLElement {
         });
     }
 
+    // Specify audio panning
+    async setPanning(panning) {
+
+        // Error checking
+        if (!Number.isFinite(panning) ||panning < -1 || panning > +1) {
+            throw new RangeError(
+                "Panning must be a number from -1 to +1.");
+        }
+
+        // Configure instance fields
+        this.#panning = panning;
+
+        // Send the panning to the core
+        await this.#core.toCore({
+            command : "setPanning",
+            promised: true,
+            sim     : this.#pointer,
+            panning : panning
+        });
+    }
+
     // Specify a new communication peer
     async setPeer(peer = null) {