Add ability to reshape analog sticks from square/circle to octagon and make the analog stick mapping indicator pretty.

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

@@ -9,12 +9,57 @@
 
 namespace ControllerEmu
 {
+// An abstract class representing the plastic shell that limits an analog stick's movement.
+class StickGate
+{
+public:
+  // Angle is in radians and should be non-negative
+  virtual ControlState GetRadiusAtAngle(double ang) const = 0;
+};
+
+// An octagon-shaped stick gate is found on most Nintendo GC/Wii analog sticks.
+class OctagonStickGate : public StickGate
+{
+public:
+  explicit OctagonStickGate(ControlState radius);
+  ControlState GetRadiusAtAngle(double ang) const override;
+
+  static ControlState ComputeRadiusAtAngle(double ang);
+
+  const ControlState m_radius;
+};
+
+// A round-shaped stick gate. Possibly found on 3rd-party accessories.
+class RoundStickGate : public StickGate
+{
+public:
+  explicit RoundStickGate(ControlState radius);
+  ControlState GetRadiusAtAngle(double ang) const override;
+
+private:
+  const ControlState m_radius;
+};
+
+// A square-shaped stick gate. e.g. keyboard input.
+class SquareStickGate : public StickGate
+{
+public:
+  explicit SquareStickGate(ControlState half_width);
+  ControlState GetRadiusAtAngle(double ang) const override;
+
+  static ControlState ComputeRadiusAtAngle(double ang);
+
+private:
+  const ControlState m_half_width;
+};
+
 class AnalogStick : public ControlGroup
 {
 public:
   enum
   {
-    SETTING_RADIUS,
+    SETTING_INPUT_RADIUS,
+    SETTING_INPUT_SHAPE,
     SETTING_DEADZONE,
   };
 
@@ -24,10 +69,28 @@ public:
     ControlState y{};
   };
 
-  // The GameCube controller and Wiimote attachments have a different default radius
-  AnalogStick(const char* name, ControlState default_radius);
-  AnalogStick(const char* name, const char* ui_name, ControlState default_radius);
+  AnalogStick(const char* name, std::unique_ptr<StickGate>&& stick_gate);
+  AnalogStick(const char* name, const char* ui_name, std::unique_ptr<StickGate>&& stick_gate);
 
-  StateData GetState();
+  StateData GetState(bool adjusted = true);
+
+  // Angle is in radians and should be non-negative
+  ControlState GetGateRadiusAtAngle(double ang) const;
+  ControlState GetDeadzoneRadiusAtAngle(double ang) const;
+  ControlState GetInputRadiusAtAngle(double ang) const;
+
+private:
+  ControlState CalculateInputShapeRadiusAtAngle(double ang) const;
+
+  std::unique_ptr<StickGate> m_stick_gate;
 };
+
+// An AnalogStick with an OctagonStickGate
+class OctagonAnalogStick : public AnalogStick
+{
+public:
+  OctagonAnalogStick(const char* name, ControlState gate_radius);
+  OctagonAnalogStick(const char* name, const char* ui_name, ControlState gate_radius);
+};
+
 }  // namespace ControllerEmu