Virtual Notch settings and UI for octagonal stick

Source/Core/InputCommon/ControllerEmu/ControlGroup/AnalogStick.cpp

@@ -65,6 +65,12 @@ OctagonAnalogStick::OctagonAnalogStick(const char* name_, const char* ui_name_,
                                        ControlState gate_radius)
     : AnalogStick(name_, ui_name_, std::make_unique<ControllerEmu::OctagonStickGate>(gate_radius))
 {
+  AddVirtualNotchSetting(&m_virtual_notch_setting, 45);
+}
+
+ControlState OctagonAnalogStick::GetVirtualNotchSize() const
+{
+  return m_virtual_notch_setting.GetValue() * MathUtil::TAU / 360;
 }
 
 }  // namespace ControllerEmu

Source/Core/InputCommon/ControllerEmu/ControlGroup/AnalogStick.h

@@ -33,6 +33,11 @@ class OctagonAnalogStick : public AnalogStick
 public:
   OctagonAnalogStick(const char* name, ControlState gate_radius);
   OctagonAnalogStick(const char* name, const char* ui_name, ControlState gate_radius);
+
+  ControlState GetVirtualNotchSize() const override;
+
+private:
+  SettingValue<double> m_virtual_notch_setting;
 };
 
 }  // namespace ControllerEmu

Source/Core/InputCommon/ControllerEmu/ControlGroup/ControlGroup.cpp

@@ -28,6 +28,17 @@ ControlGroup::ControlGroup(std::string name_, std::string ui_name_, const GroupT
 {
 }
 
+void ControlGroup::AddVirtualNotchSetting(SettingValue<double>* value, double max_virtual_notch_deg)
+{
+  AddSetting(value,
+             {_trans("Virtual Notches"),
+              // i18n: The degrees symbol.
+              _trans("°"),
+              // i18n: Snap the thumbstick position to the nearest octagonal axis.
+              _trans("Snap the thumbstick position to the nearest octagonal axis.")},
+             0, 0, max_virtual_notch_deg);
+}
+
 void ControlGroup::AddDeadzoneSetting(SettingValue<double>* value, double maximum_deadzone)
 {
   AddSetting(value,

Source/Core/InputCommon/ControllerEmu/ControlGroup/ControlGroup.h

@@ -82,6 +82,8 @@ public:
         std::make_unique<NumericSetting<T>>(value, details, default_value_, min_value, max_value));
   }
 
+  void AddVirtualNotchSetting(SettingValue<double>* value, double max_virtual_notch_deg);
+
   void AddDeadzoneSetting(SettingValue<double>* value, double maximum_deadzone);
 
   template <typename T>

Source/Core/InputCommon/ControllerEmu/StickGate.cpp

@@ -48,6 +48,16 @@ std::optional<double> GetRayLineIntersection(Common::DVec2 ray, Common::DVec2 po
   return diff.Cross(-point1) / dot;
 }
 
+double GetNearestNotch(double angle, double virtual_notch_angle)
+{
+  constexpr auto sides = 8;
+  constexpr auto rounding = MathUtil::TAU / sides;
+  const auto closest_notch = std::round(angle / rounding) * rounding;
+  const auto angle_diff =
+      std::fmod(angle - closest_notch + MathUtil::PI, MathUtil::TAU) - MathUtil::PI;
+  return std::abs(angle_diff) < virtual_notch_angle / 2 ? closest_notch : angle;
+}
+
 Common::DVec2 GetPointFromAngleAndLength(double angle, double length)
 {
   return Common::DVec2{std::cos(angle), std::sin(angle)} * length;
@@ -276,16 +286,24 @@ ReshapableInput::ReshapeData ReshapableInput::Reshape(ControlState x, ControlSta
   y -= m_center.y;
 
   // TODO: make the AtAngle functions work with negative angles:
-  const ControlState angle = std::atan2(y, x) + MathUtil::TAU;
+  ControlState angle = std::atan2(y, x) + MathUtil::TAU;
 
-  const ControlState gate_max_dist = GetGateRadiusAtAngle(angle);
   const ControlState input_max_dist = GetInputRadiusAtAngle(angle);
+  ControlState gate_max_dist = GetGateRadiusAtAngle(angle);
 
   // If input radius (from calibration) is zero apply no scaling to prevent division by zero.
   const ControlState max_dist = input_max_dist ? input_max_dist : gate_max_dist;
 
   ControlState dist = Common::DVec2{x, y}.Length() / max_dist;
 
+  const double virtual_notch_size = GetVirtualNotchSize();
+
+  if (virtual_notch_size > 0.0 && dist >= MINIMUM_NOTCH_DISTANCE)
+  {
+    angle = GetNearestNotch(angle, virtual_notch_size);
+    gate_max_dist = GetGateRadiusAtAngle(angle);
+  }
+
   // If the modifier is pressed, scale the distance by the modifier's value.
   // This is affected by the modifier's "range" setting which defaults to 50%.
   if (modifier)

Source/Core/InputCommon/ControllerEmu/StickGate.h

@@ -15,6 +15,9 @@
 
 namespace ControllerEmu
 {
+// Minimum stick distance from the center before virtual notches are applied.
+constexpr ControlState MINIMUM_NOTCH_DISTANCE = 0.9;
+
 // An abstract class representing the plastic shell that limits an analog stick's movement.
 class StickGate
 {
@@ -85,6 +88,8 @@ public:
 
   ControlState GetDeadzonePercentage() const;
 
+  virtual ControlState GetVirtualNotchSize() const { return 0.0; };
+
   virtual ControlState GetGateRadiusAtAngle(double angle) const = 0;
   virtual ReshapeData GetReshapableState(bool adjusted) = 0;
   virtual ControlState GetDefaultInputRadiusAtAngle(double ang) const;