VideoCommon: Add Free Look camera with separate modes

Source/Core/VideoCommon/FreeLookCamera.h

@@ -0,0 +1,66 @@
+// Copyright 2020 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <optional>
+
+#include "Common/Matrix.h"
+#include "VideoCommon/VideoConfig.h"
+
+class PointerWrap;
+
+class CameraController
+{
+public:
+  CameraController() = default;
+  virtual ~CameraController() = default;
+
+  CameraController(const CameraController&) = delete;
+  CameraController& operator=(const CameraController&) = delete;
+
+  CameraController(CameraController&&) = delete;
+  CameraController& operator=(CameraController&&) = delete;
+
+  virtual Common::Matrix44 GetView() = 0;
+
+  virtual void MoveVertical(float amt) = 0;
+  virtual void MoveHorizontal(float amt) = 0;
+
+  virtual void Zoom(float amt) = 0;
+
+  virtual void Rotate(const Common::Vec3& amt) = 0;
+
+  virtual void Reset() = 0;
+
+  virtual void DoState(PointerWrap& p) = 0;
+};
+
+class FreeLookCamera
+{
+public:
+  void SetControlType(FreelookControlType type);
+  Common::Matrix44 GetView();
+
+  void MoveVertical(float amt);
+  void MoveHorizontal(float amt);
+
+  void Zoom(float amt);
+
+  void Rotate(const Common::Vec3& amt);
+
+  void Reset();
+
+  void DoState(PointerWrap& p);
+
+  bool IsDirty() const;
+
+private:
+  bool m_dirty = false;
+  std::optional<FreelookControlType> m_current_type;
+  std::unique_ptr<CameraController> m_camera_controller;
+};
+
+extern FreeLookCamera g_freelook_camera;