orthanc-stone: OrthancStone/Sources/Toolbox/GeometryToolbox.cpp comparison

added DebugDrawing2D and GeometryToolbox::IntersectLineAndSegment()

author	Sebastien Jodogne <s.jodogne@gmail.com>
date	Fri, 27 Sep 2024 22:14:36 +0200
parents	16c01cc201e7
children

comparison

equal deleted inserted replaced

-:71d6ad7036b7
+:340bde744884
 else
 {
 return false;
 }
 }
+static bool SolveLineIntersectionSystem(double& x,
+double& y,
+double& s,
+double& t,
+double x1, double y1,
+double x2, double y2,
+double x3, double y3,
+double x4, double y4)
+{
+// https://en.wikipedia.org/wiki/Intersection_(geometry)#Two_line_segments
+const double a1 = x2 - x1;
+const double b1 = -x4 + x3;
+const double c1 = x3 - x1;
+const double a2 = y2 - y1;
+const double b2 = -y4 + y3;
+const double c2 = y3 - y1;
+const double denominator = a1 * b2 - a2 * b1;
+if (LinearAlgebra::IsCloseToZero(denominator))
+{
+return false;
+}
+else
+{
+// This is Cramer's rule
+s = (c1 * b2 - c2 * b1) / denominator;
+t = (a1 * c2 - a2 * c1) / denominator;
+x = x1 + s * (x2 - x1);
+y = y1 + s * (y2 - y1);
+return true;
+}
+}
+bool IntersectTwoLines(double& x,
+double& y,
+double ax1,
+double ay1,
+double ax2,
+double ay2,
+double bx1,
+double by1,
+double bx2,
+double by2)
+{
+double s, t;
+return SolveLineIntersectionSystem(x, y, s, t, ax1, ay1, ax2, ay2, bx1, by1, bx2, by2);
+}
+bool IntersectLineAndSegment(double& x,
+double& y,
+double lineX1,
+double lineY1,
+double lineX2,
+double lineY2,
+double segmentX1,
+double segmentY1,
+double segmentX2,
+double segmentY2)
+{
+double s, t;
+if (SolveLineIntersectionSystem(x, y, s, t, lineX1, lineY1, lineX2, lineY2, segmentX1, segmentY1, segmentX2, segmentY2))
+{
+return (t >= 0 && t <= 1);
+}
+else
+{
+return false;
+}
+}
 }
 }

Mercurial > hg > orthanc-stone