Adjust emulated rumble strength (#1288)

app/src/main/java/com/limelight/binding/input/ControllerHandler.java

@@ -2121,7 +2121,16 @@ public class ControllerHandler implements InputManager.InputDeviceListener, UsbD
             else if (foundMatchingDevice && !vibrated && prefConfig.vibrateFallbackToDevice) {
                 // We found a device to vibrate but it didn't have rumble support. The user
                 // has requested us to vibrate the device in this case.
-                rumbleSingleVibrator(deviceVibrator, lowFreqMotor, highFreqMotor);
+
+                // We cast the unsigned short value to a signed int before multiplying by
+                // the preferred strength. The resulting value is capped at 65534 before
+                // we cast it back to a short so it doesn't go above 100%.
+                short lowFreqMotorAdjusted = (short)(Math.min((((lowFreqMotor & 0xffff)
+                        * prefConfig.vibrateFallbackToDeviceStrength) / 100), Short.MAX_VALUE*2));
+                short highFreqMotorAdjusted = (short)(Math.min((((highFreqMotor & 0xffff)
+                        * prefConfig.vibrateFallbackToDeviceStrength) / 100), Short.MAX_VALUE*2));
+
+                rumbleSingleVibrator(deviceVibrator, lowFreqMotorAdjusted, highFreqMotorAdjusted);
             }
         }
     }