diff --git a/include/input/Input.h b/include/input/Input.h
index 456977b..17672d1 100644
--- a/include/input/Input.h
+++ b/include/input/Input.h
@@ -196,6 +196,13 @@
 #define MAX_POINTER_ID 31
 
 /*
+ * Number of high resolution mouse scroll units for one detent (mouse wheel click), as defined in
+ * evdev. This is relevant when an input device is emitting REL_WHEEL_HI_RES or REL_HWHEEL_HI_RES
+ * events.
+ */
+constexpr int32_t kEvdevMouseHighResScrollUnitsPerDetent = 120;
+
+/*
  * Declare a concrete type for the NDK's input event forward declaration.
  */
 struct AInputEvent {
diff --git a/include/input/VirtualInputDevice.h b/include/input/VirtualInputDevice.h
index 9bbaa0c..9fbae73 100644
--- a/include/input/VirtualInputDevice.h
+++ b/include/input/VirtualInputDevice.h
@@ -77,6 +77,8 @@
 
 private:
     static const std::map<int, int> BUTTON_CODE_MAPPING;
+    int32_t mAccumulatedHighResScrollX;
+    int32_t mAccumulatedHighResScrollY;
 };
 
 class VirtualTouchscreen : public VirtualInputDevice {