# HConstantFrameRate

## Functions

| `HConstantFrameRate`
| `~HConstantFrameRate`
HBaseView * | `GetView`
void | `UpdateLevel`
bool | `GetMode`
void | `Init`
void | `Shutdown`
bool | `GetActive`
void | `Watch`
void | `Start`
void | `Stop`
void | `IncreaseDetailTemp`
bool | `ViewpointHasChanged`
void | `SetDetailIncMode`
void | `SetDetailIncOnIdleMode`
`DetailChangeMode` | `GetDetailIncMode`
void | `SetDetailDecMode`
`DetailChangeMode` | `GetDetailDecMode`
void | `ResetListPointers`
float | `GetTargetFrameRate`
void | `SetTargetFrameRate`
void | `SetDeadZone`
void | `SetEmergencyDetailDecrease`
void | `SetActivityType`
`HActivityType` | `GetActivityType`
int | `GetSimpLevel`
void | `AdjustLodOptions`
bool | `GetDetailIncreaseState`
void | `SetDetailLevel`
HConstFRSimpType * | `GetSimpType`
void | `SetSimpLevel`
void | `AdjustDefaultDetailLevelToModel`
void | `SetDisableIncreaseTemp`
void | `InitiateDelay`
int | `GetDetailLevelNum`
int | `GetTotalDetailLevelNum`
void | `SetWatchActivity`
void | `MajorDetailDecrease`
void | `MajorDetailIncrease`
bool | `Tick`

## Detailed Description

class HConstantFrameRate

  The HConstantFrameRate class provides support for maintaining a constant framerate when rendering.

  HConstantFrameRate stores and manages ‘simplification-level’ objects which are used as fallbacks during rendering, in order to maintain a constant framerate. It also includes logic to determine the current framerate and if fallback is necessary and how much.

  Public Functions

  HConstantFrameRate(HBaseView *view)

    Constructs a new HConstantFrameRatge Object.

    Parameters

      view – Pointer to HBaseView object

  virtual ~HConstantFrameRate()
  inline HBaseView *GetView()
    Returns

      A pointer to the HBaseView object.

  void UpdateLevel(int SimpLevel, int SimpListPos)

    This method calls update on the simplication type associated with SimpListPos with the given SimpLevel.

    Parameters

      - SimpLevel – Simplification Level

      - SimpListPos – Position in current Simplification Level

  bool GetMode(HConstFRSimpType ***sd = 0L, float *target_framerate = 0L, int *length = 0L)

    This method lets you retrieve the simplification type list, its length and the target frame rate. Please do NOT use the pointers to the objects returned to change the their values. If you want to modify the target frame rate, use the SetTargetFrameRate() method. If you want to update the simplification type list, please use the Init() method.

    Parameters

      - sd – If sd is not 0, the method returns a pointer to the simplification type list. This is a read- only array. If you want to update the list, use the Init() method.

      - target_framerate – If target_framerate is not 0, the method returns the desired update rate for the scene, in frames per second.

      - length – If length is not 0, the method returns the length of the simplification array.

    Returns

      True if there is a simplification type list and false if none has been set up.

  void Init(float target_framerate = 20.0, HConstFRSimpType **sd = 0, int length = 0, float deadzone = 3.0)

    Initializes constant frame rate mode, sets the target framerate, and supplies a list of geometry simplification levels. The levels are used by the internal framereate logic to degrade the visual quality of the geometry in the scene in order to maintain the target framerate. If no list of simplification levels is provided, a default list is used.

    Parameters

      - target_framerate – The desired update rate for the scene, in frames per second.

      - sd – A pointer to an array of simplification types. Passed by reference.

      - length – The length of the simplification list.

      - deadzone – Allowed variance from target framerate

  void Shutdown()

    This method clears the simplification types list.

  inline bool GetActive()
    Returns

      True if constant framerate watch is activated and false if otherwise.

  void Watch()

    This method checks the update time for every frame and calls AdjustDetail() with a frames per second value. This method updates the scene if the view position has changed since the last update OR different activity that is relevant for the framerate has occured.

  void Start()

    If the simplification type list is set along with the deadzone and target framerate, this method activates the constant framerate functionality. It starts the timer. The watch function will also begin making adjustments to the scene according to the state variables that have been set. This function is normally called when an operator is started (e.g. mouse down event on rotate).

  void Stop()

    Deactivates the constant frame rate functionality. This function is normally called if an operator is stopped (e.g. mouse up event on rotate).

  void IncreaseDetailTemp()

    Temporarily bumps up the detail level if e.g. no mouse movement has occured Also adjust the base detail level based on the draw time of the frames This function is usually called from a timer event in the main application.

  bool ViewpointHasChanged(bool update = true)

    Determines if the viewpoint has changed for the associated scene.

    Parameters

      update – Pass true if you want the new viewpoint to be recorded if it has changed. Default is true.

    Returns

      True if the viewpoint has changed and false if otherwise.

  inline void SetDetailIncMode(DetailChangeMode mode)

    This method sets the state of detail increase mode which tells the framerate logic whether to try a lower simplification level when the actual framerate exceeds the target frame rate.

    Parameters

      mode – New Detail change mode

  inline void SetDetailIncOnIdleMode(DetailChangeMode mode)
  inline DetailChangeMode GetDetailIncMode()
    Returns

      The current state of detail increase mode which determines if the framerate logic should be allowed to try a lower simplification level if the actual framerate exceeds the target framerate.

  inline void SetDetailDecMode(DetailChangeMode mode)

    Sets the state of the detail decrease mode which determines if the framerate logic should be allowed to try increase the simplification level if the actual framerate is less than the target framerate.

    Parameters

      mode – New Detail decrease mode

  inline DetailChangeMode GetDetailDecMode()
    Returns

      The state of detail decrease mode which determines if the framerate logic should be allowed to try increase the simplification level if the actual framerate is less than the target framerate.

  inline void ResetListPointers()

    Resets the simplification list and level pionters.

  inline float GetTargetFrameRate()
    Returns

      Target framerate which we want the scene to maintain.

  inline void SetTargetFrameRate(float framerate)

    Sets the new target framerate which we want the scene to maintain during rendering.

    Parameters

      framerate – New target framerate

  inline void SetDeadZone(float deadzone)

    Sets the new dead zone around the target framerate. Framerate changes in that area will not result in detail level changes

    Parameters

      deadzone – new dead zone

  inline void SetEmergencyDetailDecrease(bool detaildecrease)

    Sets the emergency decrease feature which allows sharp drops in detail level if the framerate is very low.

    Parameters

      detaildecrease – Turn detaildecrease on/off

  inline void SetActivityType(HActivityType at)

    This method sets the status of the activity flag. The information is used by this class to determine how to maintain the framerate. This method supersedes SetNoActivity().

    Parameters

      at – Pass the current activity type which can be NoActivity, MovementActivity, CuttingPlaneActivity or GeneralActivity.

  inline HActivityType GetActivityType()
    Returns

      The state of the activity flag which can be NoActivity, MovementActivity, CuttingPlaneActivity or GeneralActivity. This flag affects the constant framerate logic.

  inline int GetSimpLevel()
    Returns

      Current simplification level.

  void AdjustLodOptions()

    This method adjusts the LOD rendering settings. If there is a ConstFRLodClampType in the simplification list, this method sets the LOD clamp value to the simple level maximum. If there is a ConstFRLodThresholdType in the simplification list, then this method performs a calculation based on the simple level maximum to set the LOD threshold.

    Returns

      State of detail increase flag.

  inline bool GetDetailIncreaseState()
  inline void SetDetailLevel(int listpos, int simplevel)

    Sets the default detail level before the framerate logic is started.

    Parameters

      - listpos – simplification type

      - simplevel – simplification level for given type

  HConstFRSimpType *GetSimpType(ConstFRType stype)

    This method returns a pointer to the object in the simplification list that correctsponds to given ConstFRType.

    Parameters

      stype – The ConstFRType type you are looking for in the simplification list.

    Returns

      The HConstFRSimpType object in the simplification list whose type is the given stype.

  inline void SetSimpLevel(int simplevel)

    Sets the current simplification level.

    Parameters

      simplevel – simplification level for the scene

  void AdjustDefaultDetailLevelToModel()

    This method adjusts the default detail level by calculating the complexity of the model of the associated view.

  inline void SetDisableIncreaseTemp(bool it)
  inline void InitiateDelay()
  int GetDetailLevelNum()
  int GetTotalDetailLevelNum()
  inline void SetWatchActivity(bool wa)
  void MajorDetailDecrease()
  void MajorDetailIncrease()

  Public Static Functions

  static bool Tick(float request_time, float actual_time, void *user_data)

    Tick function called from timer manager.

    Parameters

      - request_time – Timer Parameter

      - actual_time – Timer Parameter

      - user_data – User Data

    Returns

      True if the event was processed.