X-Git-Url: https://git.brokenzipper.com/gitweb?a=blobdiff_plain;f=src%2FMoof%2FInterpolator.hh;fp=src%2FMoof%2FInterpolator.hh;h=87e3acdbcf26a517fdaaa84cfbdac1c8de1c98d4;hb=c2321281bf12a7efaedde930422c7ddbc92080d4;hp=0000000000000000000000000000000000000000;hpb=87bc17e55b0c1dc73ecc66df856d3f08fd7a7724;p=chaz%2Fyoink

diff --git a/src/Moof/Interpolator.hh b/src/Moof/Interpolator.hh
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+
+/*******************************************************************************
+
+ Copyright (c) 2009, Charles McGarvey
+ All rights reserved.
+ 
+ Redistribution   and   use  in  source  and  binary  forms,  with  or  without
+ modification, are permitted provided that the following conditions are met:
+ 
+   * Redistributions  of  source  code  must retain the above copyright notice,
+     this list of conditions and the following disclaimer.
+   * Redistributions  in binary form must reproduce the above copyright notice,
+     this  list of conditions and the following disclaimer in the documentation
+     and/or other materials provided with the distribution.
+ 
+ THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES  (INCLUDING,  BUT  NOT  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES;  LOSS  OF  USE,  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+*******************************************************************************/
+
+#ifndef _MOOF_INTERPOLATOR_HH_
+#define _MOOF_INTERPOLATOR_HH_
+
+
+namespace Mf {
+
+
+class Interpolator
+{
+	void clamp(Scalar& value)
+	{
+		if (value > 1.0)
+		{
+			switch (mode_)
+			{
+				case STOP:
+					value = 1.0;
+					stopped_ = true;
+					break;
+				case REPEAT:
+					value -= 1.0;
+					break;
+				case OSCILLATE:
+					value = 2.0 - value;
+					scale_ *= -1.0;
+					break;
+			}
+		}
+		else if (value < 0.0)
+		{
+			switch (mode_)
+			{
+				case STOP:
+					value = 0.0;
+					stopped_ = true;
+					break;
+				case REPEAT:
+					value += 1.0;
+					break;
+				case OSCILLATE:
+					value = -value;
+					scale_ *= -1.0;
+					break;
+			}
+		}
+	}
+
+public:
+	typedef enum
+	{
+		STOP		= 0,
+		REPEAT		= 1,
+		OSCILLATE	= 2
+	} Mode;
+
+	void init(Scalar seconds = 1.0, Mode mode = STOP)
+	{
+		scale_ = 1.0 / seconds;
+		alpha_ = 0.0;
+		setMode(mode);
+	}
+
+
+	void setMode(Mode mode)
+	{
+		mode_ = mode;
+		stopped_ = false;
+	}
+
+
+	void update(Scalar dt)
+	{
+		if (!stopped_)
+		{
+			alpha_ += dt * scale_;
+			clamp(alpha_);
+			calculate(alpha_);
+		}
+	}
+
+	virtual void calculate(Scalar alpha) = 0;
+
+private:
+	Scalar	alpha_;
+	Mode	mode_;
+	Scalar	scale_;
+	bool	stopped_;
+};
+
+template <class T>
+class InterpolatorBase : public Interpolator
+{
+public:
+	void init(Scalar seconds = 1.0, Mode mode = STOP)
+	{
+		Interpolator::init(seconds, mode);
+
+		calculate(0.0);	// set value
+		calculate(0.0);	// set previous
+	}
+
+	void calculate(Scalar alpha)
+	{
+		previous_ = value_;
+		calculate(value_, alpha);
+	}
+
+	virtual void calculate(T& value, Scalar alpha) = 0;
+
+	const T& getValue()
+	{
+		return value_;
+	}
+
+	const T getState(Scalar alpha)
+	{
+		return cml::lerp(previous_, value_, alpha);
+	}
+
+private:
+	T value_;
+	T previous_;
+};
+
+
+template <class T, int D>
+class BinomialInterpolator : public InterpolatorBase<T>
+{
+public:
+	BinomialInterpolator() {}
+
+	explicit BinomialInterpolator(const T coefficients[D+1],
+			Scalar seconds = 1.0, Interpolator::Mode mode = Interpolator::STOP)
+	{
+		init(coefficients, seconds, mode);
+	}
+
+	void init(const T coefficients[D+1], Scalar seconds = 1.0,
+			Interpolator::Mode mode = Interpolator::STOP)
+	{
+		Scalar fac[D+1];
+
+		fac[0] = 1.0;
+		fac[1] = 1.0;
+
+		// build an array of the computed factorials we will need
+		for (int i = 2; i <= D; i++)
+		{
+			fac[i] = i * fac[i - 1];
+		}
+
+		// combine the coefficients for fast updating
+		for (int i = 0; i <= D; i++)
+		{
+			// n! / (k! * (n - k)!)
+			coefficients_[i] = coefficients[i] * fac[D] / (fac[i] * fac[D - i]);
+		}
+
+		InterpolatorBase<T>::init(seconds, mode);
+	}
+
+
+	void calculate(T& value, Scalar alpha)
+	{
+		Scalar beta = 1.0 - alpha;
+
+		value = coefficients_[0] * std::pow(beta, D);
+
+		for (int i = 1; i <= D; i++)
+		{
+			value += coefficients_[i] * std::pow(beta, D - i) *
+				std::pow(alpha, i);
+		}
+	}
+
+private:
+	T coefficients_[D+1];
+};
+
+
+template <class T>
+class BinomialInterpolator<T,1> : public InterpolatorBase<T>
+{
+public:
+	BinomialInterpolator() {}
+
+	explicit BinomialInterpolator(const T coefficients[2], Scalar seconds = 1.0,
+			Interpolator::Mode mode = Interpolator::STOP)
+		//InterpolatorBase<T>(seconds, mode)
+	{
+		init(coefficients, seconds, mode);
+	}
+
+	void init(const T coefficients[2], Scalar seconds = 1.0,
+			Interpolator::Mode mode = Interpolator::STOP)
+	{
+		a_ = coefficients[0];
+		b_ = coefficients[1];
+
+		InterpolatorBase<T>::init(seconds, mode);
+	}
+
+
+	void calculate(T& value, Scalar alpha)
+	{
+		value = cml::lerp(a_, b_, alpha);
+	}
+
+private:
+	T a_;
+	T b_;
+};
+
+
+// Here are some aliases for more common interpolators.  Also see the
+// interpolation functions in cml for other types of interpolation such as
+// slerp and some multi-alpha interpolators.
+
+typedef BinomialInterpolator<Scalar, 1>	Lerps;	// linear
+typedef BinomialInterpolator<Vector2,1>	Lerpv2;
+typedef BinomialInterpolator<Vector3,1>	Lerpv3;
+typedef BinomialInterpolator<Vector4,1>	Lerpv4;
+
+typedef BinomialInterpolator<Scalar ,2>	Qerps;	// quadratic
+typedef BinomialInterpolator<Vector2,2>	Qerpv2;
+typedef BinomialInterpolator<Vector3,2>	Qerpv3;
+typedef BinomialInterpolator<Vector4,2>	Qerpv4;
+
+typedef BinomialInterpolator<Scalar ,3>	Cerps;	// cubic
+typedef BinomialInterpolator<Vector2,3>	Cerpv2;
+typedef BinomialInterpolator<Vector3,3>	Cerpv3;
+typedef BinomialInterpolator<Vector4,3>	Cerpv4;
+
+
+} // namespace Mf
+
+#endif // _MOOF_INTERPOLATOR_HH_
+
+/** vim: set ts=4 sw=4 tw=80: *************************************************/
+