camera: bank the view when the flight path curves

config.js

@@ -480,7 +480,18 @@ window.CONFIG = {
         aim: 'off',               // 'off' | 'moon'
         // aim: 'moon'             // look at the moon while flying the path
         aimEase: 0.94,            // 0 = instant turn, 0.99 = very slow
-        aimBob: 0.25              // share of the altitude bob kept while aiming
+        aimBob: 0.25,             // share of the altitude bob kept while aiming
+        // Banking when the flight path curves. The camera keeps flying the
+        // same path; roll only rotates the view around the forward axis.
+        roll: {
+            enabled: true,
+            gain: 12,             // turn-rate to bank-angle gain
+            maxDeg: 12,           // maximum bank angle
+            ease: 0.92,           // 0 = instant bank, 0.99 = very slow
+            sign: -1              // flip to +1 if the bank direction feels inverted
+            // roll: { enabled: false }
+            // roll: { gain: 20, maxDeg: 18 }
+        }
         // camera: { aim: 'moon' }                         // look at the moon
     },