//=============================================================================
  // Camera.h by Frank Luna (C) 2004 All Rights Reserved.
  //=============================================================================
  
  ifndef CAMERA_H
  define CAMERA_H
  
  include <d3dx9.h>
  include <d3dUtil.h>
  
  // Forward declaration.
  class Terrain;
  
  class Camera
  {
  public:
          Camera();
  
          const D3DXMATRIX& view() const;
          const D3DXMATRIX& proj() const;
          const D3DXMATRIX& viewProj() const;
  
          const D3DXVECTOR3& right() const;
          const D3DXVECTOR3& up() const;
          const D3DXVECTOR3& look() const;
  
          D3DXVECTOR3& pos();
  
          void lookAt(D3DXVECTOR3& pos, D3DXVECTOR3& target, D3DXVECTOR3& up);
          void setLens(float fov, float aspect, float nearZ, float farZ);
          void setSpeed(float s);
  
          // Box coordinates should be relative to world space.
          bool isVisible(const AABB& box)const;
  
          void update(float dt, Terrain* terrain, float offsetHeight);
  
  protected:
          void buildView();
          void buildWorldFrustumPlanes();
  
  protected:
          D3DXMATRIX mView;
          D3DXMATRIX mProj;
          D3DXMATRIX mViewProj;
  
          // Relative to world space.
          D3DXVECTOR3 mPosW;
          D3DXVECTOR3 mRightW;
          D3DXVECTOR3 mUpW;
          D3DXVECTOR3 mLookW;
  
          float mSpeed;
  
          // Frustum Planes
          D3DXPLANE mFrustumPlanes[6]; // [0] = near
                                       // [1] = far
                                       // [2] = left
                                       // [3] = right
                                       // [4] = top
                                       // [5] = bottom
  };
  
  endif // CAMERA_H