Pretty sure I'm done with triangle. Changelog next

Changelog.md

@@ -30,6 +30,7 @@ Here's the full changelog:
                 + : IIndexRangeAll<Float3>
                 + : ISplittable<Line, (Float3[] As, Float3[] Bs)>
                 + IWithinRange<Float3, float>
+                + Angle
                 + Slope
                 + Line()
                 + ToFloatArrayAll(params Line[])

Nerd_STF/Mathematics/Angle.cs

@@ -52,11 +52,15 @@ public struct Angle : IAbsolute<Angle>, IAverage<Angle>, IClamp<Angle>, ICloneab
         _ => throw new ArgumentException("Unknown type.", nameof(valueType)),
     };
 
-    public static Angle FromVerts(Float3 endA, Float3 middleB, Float3 endC)
+    public static Angle FromLines(Line ab, Line bc)
+    {
+        if (ab.b != bc.a) throw new DisconnectedLinesException(ab, bc);
+        return FromPoints(ab.a, ab.b, bc.b);
+    }
+    public static Angle FromPoints(Float3 endA, Float3 middleB, Float3 endC)
     {
         endA -= middleB;
         endC -= middleB;
-
         float dot = Float3.Dot(endA, endC);
         return Mathf.ArcCos(dot * endA.InverseMagnitude * endC.InverseMagnitude);
     }

Nerd_STF/Mathematics/Geometry/Line.cs

@@ -16,6 +16,7 @@ public class Line : IAverage<Line>, IClosestTo<Float3>, IContains<Float3>, IEqua
     public static Line One => (Float3.Zero, Float3.One);
     public static Line Zero => (Float3.Zero, Float3.Zero);
 
+    public Angle Angle => Mathf.ArcTan(Slope);
     public float Length => (b - a).Magnitude;
     public Float3 Midpoint => (a + b) / 2;
     public float Slope => (b.y - a.y) / (b.x - a.x);
@@ -253,5 +254,5 @@ public class Line : IAverage<Line>, IClosestTo<Float3>, IContains<Float3>, IEqua
     public static implicit operator Line(Fill<Int3> fill) => new(fill);
     public static implicit operator Line(Fill<float> fill) => new(fill);
     public static implicit operator Line(Fill<int> fill) => new(fill);
-    public static implicit operator Line((Float3 a, Float3 b) tuple) => (tuple.a, tuple.b);
+    public static implicit operator Line((Float3 a, Float3 b) tuple) => new(tuple.a, tuple.b);
 }

Nerd_STF/Mathematics/Geometry/Triangle.cs

@@ -45,6 +45,10 @@ public class Triangle : IClosestTo<Float3>, IContains<Float3>,
         }
     }
 
+    public Angle AngleABC => Angle.FromPoints(a, b, c);
+    public Angle AngleBCA => Angle.FromPoints(b, c, a);
+    public Angle AngleCAB => Angle.FromPoints(c, a, b);
+
     public Float3 a, b, c;
 
     public Triangle() : this(Float3.Zero, Float3.Zero, Float3.Zero) { }
@@ -176,6 +180,24 @@ public class Triangle : IClosestTo<Float3>, IContains<Float3>,
         return result;
     }
 
+    public Float3 ClosestTo(Float3 point)
+    {
+        Float3 abClosest = AB.ClosestTo(point),
+               bcClosest = BC.ClosestTo(point),
+               caClosest = CA.ClosestTo(point);
+
+        // Very inefficient way to select the closest point.
+
+        float abDist = (abClosest - point).Magnitude,
+              bcDist = (bcClosest - point).Magnitude,
+              caDist = (caClosest - point).Magnitude;
+
+        float min = Mathf.Min(abDist, bcDist, caDist);
+        if (abDist == min) return abClosest;
+        else if (bcDist == min) return bcClosest;
+        else return caClosest;
+    }
+
     public bool Equals(Triangle? other) => other is not null && a == other.a
         && b == other.b && c == other.c;
     public override bool Equals(object? obj)
@@ -191,7 +213,7 @@ public class Triangle : IClosestTo<Float3>, IContains<Float3>,
         Triangle pab = (point, a, b),
                  pbc = (point, b, c),
                  pca = (point, c, a);
-        return Mathf.Absolute(Area - (pab.Area + pbc.Area + pca.Area)) < 0.025f;
+        return Mathf.Absolute(Area - (pab.Area + pbc.Area + pca.Area)) < 0.05f;
     }
 
     public Float3[] GetAllVerts() => new[] { a, b, c };