CWE-ou-minkata/Sources/Plasma/NucleusLib/pnTimer/plTimedValue.h

/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

This program is free software: you can redistribute it and/or modify
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This program is distributed in the hope that it will be useful,
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

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 or by snail mail at:
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*==LICENSE==*/

#ifndef plTimedValue_inc
#define plTimedValue_inc

#include "hsTimer.h"
#include "hsStream.h"

// plTimedValue
// To use, replace your member var of type T with plTimedValue<T>.
// You can then pretty much treat it as normal. To set it to interpolate
// to a new value over secs seconds, use Set(newVal, secs).
// For I/O, see plTimedSimple and plTimedCompound.
template <class T> class plTimedValue
{
protected:
    T           fGoal;
    T           fInit;
    double      fStart;
    hsScalar    fInvSecs;

public:
    plTimedValue() {}
    plTimedValue(const plTimedValue<T>& o) { Set(o, 0.f); }
    plTimedValue(const T& v) { Set(v, 0.f); }

    plTimedValue<T>& operator=(const plTimedValue<T>& o) { return Set(o, 0.f); }
    plTimedValue<T>& operator=(const T& v) { return Set(v, 0.f); }

    plTimedValue<T>& Set(const T& v, hsScalar secs=0);

    operator T () const { return Value(); }

    T Value() const;

};

// Read/Writable version of plTimedValue, for intrinsic types (e.g. int, float, bool).
// Must be a type that hsStream has an overloaded ReadSwap/WriteSwap defined.
template <class T> class plTimedSimple : public plTimedValue<T>
{
public:
    plTimedSimple<T>& operator=(const plTimedValue<T>& o) { return Set(o, 0.f); }
    plTimedSimple<T>& operator=(const T& v) { return Set(v, 0.f); }

    plTimedSimple<T>& Set(const T& v, hsScalar secs=0) { plTimedValue<T>::Set(v, secs); return *this; }

    void Read(hsStream* s);
    void Write(hsStream* s) const;
};

// Read/Writable version of plTimedValue, for compound types (e.g. hsVector3, hsColorRGBA).
// May be any type that has Read(hsStream*)/Write(hsStream*) defined.
template <class T> class plTimedCompound : public plTimedValue<T>
{
public:
    plTimedCompound<T>& operator=(const plTimedValue<T>& o) { return Set(o, 0.f); }
    plTimedCompound<T>& operator=(const T& v) { return Set(v, 0.f); }

    plTimedCompound<T>& Set(const T& v, hsScalar secs=0) { plTimedValue<T>::Set(v, secs); return *this; }

    void Read(hsStream* s);
    void Write(hsStream* s) const;
};

template <class T> 
plTimedValue<T>& plTimedValue<T>::Set(const T& v, hsScalar secs)
{
    if( secs <= 0 )
    {
        fGoal = fInit = v;
        fInvSecs = 0;
    }
    else
    {
        fInit = Value();
        fStart = hsTimer::GetSysSeconds();
        fInvSecs = 1.f / secs;
        fGoal = v;
    }
    return *this;
}

template <class T> 
T plTimedValue<T>::Value() const
{
    if( fInvSecs > 0 )
    {
        hsScalar t = (hsScalar)((hsTimer::GetSysSeconds() - fStart) * fInvSecs);
        hsAssert(t >= 0, "Moving back in time");

        if( t < 1.f )
            return fGoal * t + fInit * (1.f - t);

    }
    return fGoal;
}


template <class T> 
void plTimedSimple<T>::Read(hsStream* s)
{
    T val;
    s->ReadSwap(&val);
    Set(val, 0.f);
}

template <class T> 
void plTimedSimple<T>::Write(hsStream* s) const
{
    T val = this->Value();
    s->WriteSwap(val);
}

template <class T> 
void plTimedCompound<T>::Read(hsStream* s)
{
    T val;
    val.Read(s);
    Set(val, 0.f);
}

template <class T> 
void plTimedCompound<T>::Write(hsStream* s) const
{
    T val = this->Value();
    val.Write(s);
}

#endif // plTimedValue_inc