xrb_framehandler.hpp

// ///////////////////////////////////////////////////////////////////////////
// xrb_framehandler.hpp by Victor Dods, created 2004/09/06
// ///////////////////////////////////////////////////////////////////////////
// Unless a different license was explicitly granted in writing by the
// copyright holder (Victor Dods), this software is freely distributable under
// the terms of the GNU General Public License, version 2.  Any works deriving
// from this work must also be released under the GNU GPL.  See the included
// file LICENSE for details.
// ///////////////////////////////////////////////////////////////////////////

#if !defined(_XRB_FRAMEHANDLER_HPP_)
#define _XRB_FRAMEHANDLER_HPP_

#include "xrb.hpp"

namespace Xrb
{

class FrameHandler
{
public:

    FrameHandler ();
    virtual ~FrameHandler ();

    inline Float MostRecentFrameTime () const { return Max(m_most_recent_time, 0.0f); }
    inline Uint32 FrameCount () const { return m_frame_count; }

    // this function will skip time so that the next call to ProcessFrame
    // incurs a time delta of 0.
    inline void SetSkipTime (bool const skip_time) { m_skip_time = skip_time; }

    void ProcessFrame (Float const time);

protected:

    inline Float FrameTime () const
    {
        ASSERT1(m_lock > 0);
        return m_most_recent_time;
    }
    inline Float FrameDT () const
    {
        ASSERT1(m_lock > 0);
        return m_frame_dt;
    }

    virtual void HandleFrame () = 0;

private:

    // handles setting up all the member variables for starting a frame
    void StartFrame (Float const time);
    // handles ending the frame and updating m_most_recent_time
    void EndFrame ();

    // mutual exclusion so that calls to superclass Frames work
    Uint32 m_lock;
    // the most recently processed frame's time (stores the current frame
    // time during ProcessFrame()
    Float m_most_recent_time;
    // the delta time value
    Float m_frame_dt;
    // the frame counter
    Uint32 m_frame_count;
    // indicates if the next frame should skip time and make
    // the frame's time delta 0.
    bool m_skip_time;
}; // end of class FrameHandler

} // end of namespace Xrb

#endif // !defined(_XRB_FRAMEHANDLER_HPP_)

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