Initial checkin

BeefySysLib/util/PolySpline.cpp

@@ -0,0 +1,67 @@
+#include "PolySpline.h"
+
+USING_NS_BF;
+  
+PolySpline2D::PolySpline2D()
+{
+	mCoefs = NULL;	
+}
+
+PolySpline2D::~PolySpline2D()
+{
+	delete mCoefs;	
+}
+
+void PolySpline2D::AddPt(float x, float y)
+{
+	delete mCoefs;
+	mCoefs = NULL;
+	
+	
+
+	mInputPoints.push_back(Point2D(x, y));
+}
+
+int PolySpline2D::GetLength()
+{
+	return (int) mInputPoints.size();
+}
+
+void PolySpline2D::Calculate()
+{
+	int n = (int) mInputPoints.size();
+	float* mat = new float[n*n];
+	mCoefs = new float[n];
+
+	for (int j=0; j<n; j++)
+		mat[j*n] = mInputPoints[j].mY;
+	for (int i=1; i<n; i++)
+	{	    
+	    for (int j=0; j<n-i; j++)
+		    mat[i+j*n]=(mat[(i-1)+j*n]-mat[(i-1)+(j+1)*n])/(mInputPoints[j].mX-mInputPoints[j+i].mX);	    
+	}
+
+	for (int i=0; i<n; i++)
+		mCoefs[i] = mat[i];
+
+	delete mat;	
+}
+
+float PolySpline2D::Evaluate(float x)
+{
+	if (mCoefs == NULL)
+		Calculate();
+
+	float result = mCoefs[0];
+	int n = (int) mInputPoints.size();
+	for (int i = 1; i < n; i++)
+	{	    
+		float add = mCoefs[i];
+	    for (int j = 0; j < i; j++)
+			add *= (x - mInputPoints[j].mX);
+		result += add;
+	}
+
+	return result;
+}
+