Fix check if two normal vectors are withing same plane

hypar-io · Aug 29, 2023 · 0b688a8 · 0b688a8
1 parent fa0b8d1
commit 0b688a8
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Showing 4 changed files with 14 additions and 7 deletions.
diff --git a/Elements/src/Geometry/Circle.cs b/Elements/src/Geometry/Circle.cs
@@ -220,7 +220,7 @@ public bool Intersects(Circle other, out List<Vector3> results)
             Plane planeB = new Plane(other.Center, other.Normal);
 
             // Check if two circles are on the same plane. 
-            if (Normal.IsAlmostEqualTo(other.Normal) &&
+            if (Normal.IsParallelTo(other.Normal, Vector3.EPSILON * Vector3.EPSILON) &&
                 other.Center.DistanceTo(planeA).ApproximatelyEquals(0))
             {
                 var delta = other.Center - Center;

diff --git a/Elements/src/Geometry/Ellipse.cs b/Elements/src/Geometry/Ellipse.cs
@@ -316,7 +316,7 @@ public bool Intersects(Circle circle, out List<Vector3> results)
             Plane planeB = new Plane(circle.Center, circle.Normal);
 
             // Check if circle and ellipse are on the same plane. 
-            if (Normal.IsAlmostEqualTo(circle.Normal) &&
+            if (Normal.IsParallelTo(circle.Normal, Vector3.EPSILON * Vector3.EPSILON) &&
                 circle.Center.DistanceTo(planeA).ApproximatelyEquals(0))
             {
                 // Circle and Ellipse are the same.
@@ -381,7 +381,7 @@ public bool Intersects(Ellipse other, out List<Vector3> results)
             Plane planeB = new Plane(other.Center, other.Normal);
 
             // Check if circle and ellipse are on the same plane. 
-            if (Normal.IsAlmostEqualTo(other.Normal) &&
+            if (Normal.IsParallelTo(other.Normal, Vector3.EPSILON * Vector3.EPSILON) &&
                 other.Center.DistanceTo(planeA).ApproximatelyEquals(0))
             {
                 // Ellipses are the same.

diff --git a/Elements/test/CircleTests.cs b/Elements/test/CircleTests.cs
@@ -27,6 +27,13 @@ public void CirceIntersectsCircle()
             Assert.Contains(new Vector3(1.5, 4.769696, 0), results);
             Assert.Contains(new Vector3(1.5, -4.769696, 0), results);
 
+            // Planar intersecting circles with opposite normals
+            c1 = new Circle(new Transform(new Vector3(8, 0, 0), Vector3.ZAxis.Negate()), 5);
+            Assert.True(c0.Intersects(c1, out results));
+            Assert.Equal(2, results.Count());
+            Assert.Contains(new Vector3(4, 3, 0), results);
+            Assert.Contains(new Vector3(4, -3, 0), results);
+
             // Planar touching circles
             c1 = new Circle(new Vector3(8, 0, 0), 3);
             Assert.True(c0.Intersects(c1, out results));

diff --git a/Elements/test/EllipseTests.cs b/Elements/test/EllipseTests.cs
@@ -60,9 +60,9 @@ public void EllipseIntersectsCircle()
             Assert.True(ellipse.Intersects(circle, out var results));
             Assert.Equal(4, results.Count());
 
-            // Planar intersection 3 intersections.
+            // Planar intersection 3 intersections and negative normals.
             ellipse = new Ellipse(new Vector3(1, 1), 2, 6);
-            circle = new Circle(new Vector3(-2, 1, 0), 5);
+            circle = new Circle(new Transform(new Vector3(-2, 1, 0), Vector3.ZAxis.Negate()), 5);
             Assert.True(ellipse.Intersects(circle, out results));
             Assert.Equal(3, results.Count());
 
@@ -130,9 +130,9 @@ public void EllipseIntersectsEllipse()
             Assert.True(ellipse.Intersects(other, out var results));
             Assert.Equal(4, results.Count());
 
-            // Planar intersection 3 intersections.
+            // Planar intersection 3 intersections and negative normals.
             ellipse = new Ellipse(new Vector3(1, 1), 2, 6);
-            other = new Ellipse(new Vector3(-2, 1, 0), 5, 2);
+            other = new Ellipse(new Transform(new Vector3(-2, 1, 0), Vector3.ZAxis.Negate()), 5, 2);
             Assert.True(ellipse.Intersects(other, out results));
             Assert.Equal(3, results.Count());