X-Git-Url: https://git.pterodactylus.net/?a=blobdiff_plain;f=ETL%2Ftrunk%2FETL%2F_calculus.h;h=45c8ed48960378df1a83a173a9d958fc61f76b47;hb=9459638ad6797b8139f1e9f0715c96076dbf0890;hp=8b0fa598c40757661c629fa7f02b556814f9c6e9;hpb=b3016b249333ac0ab0008d8c6c4d9029b2ff30c9;p=synfig.git

diff --git a/ETL/trunk/ETL/_calculus.h b/ETL/trunk/ETL/_calculus.h
index 8b0fa59..45c8ed4 100644
--- a/ETL/trunk/ETL/_calculus.h
+++ b/ETL/trunk/ETL/_calculus.h
@@ -1,9 +1,10 @@
 /*! ========================================================================
 ** Extended Template and Library
 ** Calculus Functional Classes Implementation
-** $Id: _calculus.h,v 1.1.1.1 2005/01/04 01:31:46 darco Exp $
+** $Id$
 **
 ** Copyright (c) 2002 Robert B. Quattlebaum Jr.
+** Copyright (c) 2008 Chris Moore
 **
 ** This package is free software; you can redistribute it and/or
 ** modify it under the terms of the GNU General Public License as
@@ -28,14 +29,14 @@
 
 #include <functional>
 
+#include "hermite"
+
 /* === M A C R O S ========================================================= */
 
 //#ifndef _EPSILON
 //#define _EPSILON		0.0000001
 //#endif
 
-#define ETL_FIXED_DERIVATIVE 1
-
 /* === T Y P E D E F S ===================================================== */
 
 /* === C L A S S E S & S T R U C T S ======================================= */
@@ -49,15 +50,27 @@ class derivative : public std::unary_function<typename T::argument_type,typename
 	typename T::argument_type epsilon;
 public:
 	explicit derivative(const T &x, const typename T::argument_type &epsilon=0.000001):func(x),epsilon(epsilon) { }
-	
+
 	typename T::result_type
 	operator()(const typename T::argument_type &x)const
 	{
-#ifdef ETL_FIXED_DERIVATIVE
 		return (func(x+epsilon)-func(x))/epsilon;
-#else
-		return (func(x)-func(x+epsilon))/epsilon;
-#endif
+	}
+};
+
+template <typename T>
+class derivative<hermite<T> > : public std::unary_function<typename hermite<T>::argument_type,typename hermite<T>::result_type>
+{
+	hermite<T> func;
+public:
+	explicit derivative(const hermite<T> &x):func(x) { }
+
+	typename hermite<T>::result_type
+	operator()(const typename hermite<T>::argument_type &x)const
+	{
+		T a = func[0], b = func[1], c = func[2], d = func[3];
+		typename hermite<T>::argument_type y(1-x);
+		return ((b-a)*y*y + (c-b)*x*y*2 + (d-c)*x*x) * 3;
 	}
 };
 
@@ -68,14 +81,14 @@ class integral : public std::binary_function<typename T::argument_type,typename
 	int samples;
 public:
 	explicit integral(const T &x, const int &samples=500):func(x),samples(samples) { }
-	
+
 	typename T::result_type
 	operator()(typename T::argument_type x,typename T::argument_type y)const
 	{
 		typename T::result_type ret=0;
 		int i=samples;
 		const typename T::argument_type increment=(y-x)/i;
-		
+
 		for(;i;i--,x+=increment)
 			ret+=(func(x)+func(x+increment))*increment/2;
 		return ret;