X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=src%2Fbezier.cpp;h=9b594a05f8fa24f9b821586b30f99b433a1104c4;hb=fe80b0a479a44182b6e7e982fb6ff33b6e17303d;hp=3fa16e35ed13cab396a7c916a43309d67d6d0e76;hpb=35f1190c8c8036ed11180656769cf0c1cbf7c2b3;p=ipdf%2Fcode.git

diff --git a/src/bezier.cpp b/src/bezier.cpp
index 3fa16e3..9b594a0 100644
--- a/src/bezier.cpp
+++ b/src/bezier.cpp
@@ -54,9 +54,11 @@ static void CubicSolveSegment(vector<Real> & roots, const Real & a, const Real &
 	Real l = a*tl*tl*tl + b*tl*tl + c*tl + d;
 	Real u = a*tu*tu*tu + b*tu*tu + c*tu + d;
 	if ((l < 0 && u < 0) || (l > 0 && u > 0))
-		return;
+		Debug("Discarding segment (no roots) l = %f (%f), u = %f (%f)", tl, l, tu, u);
+		//return;
 	
 	bool negative = (u < l); // lower point > 0, upper point < 0
+	//Debug("%ft^3 + %ft^2 + %ft + %f is negative (%f < %f) %d", a,b,c,d,u,l, negative);
 	while (tu - tl > delta)
 	{
 		Real t(tu+tl);
@@ -97,23 +99,6 @@ vector<Real> SolveCubic(const Real & a, const Real & b, const Real & c, const Re
 	tu = max;
 	CubicSolveSegment(roots, a, b, c, d, tl, tu,delta);
 	return roots;
-	/*
-		Real maxi(100);
-		Real prevRes(d);
-		for(int i = 0; i <= 100; ++i)
-		{
-			Real x(i);
-			x /= maxi;
-			Real y = a*(x*x*x) + b*(x*x) + c*x + d;
-			if (((y < Real(0)) && (prevRes > Real(0))) || ((y > Real(0)) && (prevRes < Real(0))))
-			{
-				//Debug("Found root of %fx^3 + %fx^2 + %fx + %f at %f (%f)", a, b, c, d, x, y);
-				roots.push_back(x);
-			}
-			prevRes = y;
-		}
-		return roots;
-	*/
 }
 
 /**
@@ -166,8 +151,8 @@ pair<Real, Real> BezierTurningPoints(const Real & p0, const Real & p1, const Rea
 	{
 		return pair<Real,Real>(0, 1);
 	}
-	Real a = (3*(p1-p2) + p3 - p0);
-	Real b = 2*(p2 - 2*p1 + p0);
+	Real a = ((p1-p2)*3 + p3 - p0);
+	Real b = (p2 - p1*2 + p0)*2;
 	Real c = (p1-p0);
 	if (a == 0)
 	{
@@ -179,7 +164,7 @@ pair<Real, Real> BezierTurningPoints(const Real & p0, const Real & p1, const Rea
 		return pair<Real, Real>(t, t);
 	}
 	//Debug("a, b, c are %f, %f, %f", Float(a), Float(b), Float(c));
-	if (b*b - 4*a*c < 0)
+	if (b*b - a*c*4 < 0)
 	{
 		//Debug("No real roots");
 		return pair<Real, Real>(0,1);