X-Git-Url: https://git.pterodactylus.net/?a=blobdiff_plain;f=ETL%2Ftrunk%2FETL%2F_calculus.h;h=45c8ed48960378df1a83a173a9d958fc61f76b47;hb=10607b8897203cd8c6606827e01bb94508645775;hp=279ed9129f7b0e42fe6934c67aa2c5e2f00103ce;hpb=003520b8158176c1509825eef09f46cd417dcc16;p=synfig.git

diff --git a/ETL/trunk/ETL/_calculus.h b/ETL/trunk/ETL/_calculus.h
index 279ed91..45c8ed4 100644
--- a/ETL/trunk/ETL/_calculus.h
+++ b/ETL/trunk/ETL/_calculus.h
@@ -4,6 +4,7 @@
 ** $Id$
 **
 ** 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
@@ -28,6 +29,8 @@
 
 #include <functional>
 
+#include "hermite"
+
 /* === M A C R O S ========================================================= */
 
 //#ifndef _EPSILON
@@ -56,6 +59,22 @@ public:
 };
 
 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;
+	}
+};
+
+template <typename T>
 class integral : public std::binary_function<typename T::argument_type,typename T::argument_type,typename T::result_type>
 {
 	T func;