Changing Convex2Convex2Intersection to allow representing multiple in…

…tersection points

Sources/Geometria/2D/Convex2Convex2Intersection.swift

@@ -14,12 +14,20 @@ public enum Convex2Convex2Intersection<Vector: Vector2FloatingPoint> {
     /// shape on a single vertex, or tangentially, in case of spheroids.
     case singlePoint(PointNormal<Vector>)
 
-    /// Represents cases where the convex crosses the other convex shape twice.
-    case twoPoints(PointNormal<Vector>, PointNormal<Vector>)
+    /// A set of two or more intersection points between the two convexes.
+    ///
+    /// The normals are in relation to one of the convexes.
+    case points([PointNormal<Vector>])
 
     /// Represents the case where no intersection occurs at any point.
     case noIntersection
 
+    /// Convenience for `.points([p1, p2])`.
+    @inlinable
+    public static func twoPoints(_ p1: PointNormal<Vector>, _ p2: PointNormal<Vector>) -> Self {
+        .points([p1, p2])
+    }
+
     /// Returns a new ``Convex2Convex2Intersection`` where any ``PointNormal`` value
     /// is mapped by a provided closure before being stored back into the same
     /// enum case and returned.
@@ -40,8 +48,8 @@ public enum Convex2Convex2Intersection<Vector: Vector2FloatingPoint> {
         case .singlePoint(let pointNormal):
             return .singlePoint(mapper(pointNormal, .singlePoint))
 
-        case let .twoPoints(p1, p2):
-            return .twoPoints(mapper(p1, .twoPointsFirst), mapper(p2, .twoPointsSecond))
+        case .points(let points):
+            return .points(points.enumerated().map({ mapper($0.element, .points(index: $0.offset)) }))
         }
     }
 
@@ -65,8 +73,8 @@ public enum Convex2Convex2Intersection<Vector: Vector2FloatingPoint> {
         case .singlePoint(let pointNormal):
             return .singlePoint(mapper(pointNormal, .singlePoint))
 
-        case let .twoPoints(p1, p2):
-            return .twoPoints(mapper(p1, .twoPointsFirst), mapper(p2, .twoPointsSecond))
+        case .points(let points):
+            return .points(points.enumerated().map({ mapper($0.element, .points(index: $0.offset)) }))
         }
     }
 
@@ -77,6 +85,7 @@ public enum Convex2Convex2Intersection<Vector: Vector2FloatingPoint> {
         case singlePoint
         case twoPointsFirst
         case twoPointsSecond
+        case points(index: Int)
     }
 }
 

Sources/TestCommons/Assertions.swift

@@ -244,11 +244,18 @@ public func assertEqual<T: Vector2FloatingPoint>(
         )
         """
 
-    case .twoPoints(let pn1, let pn2):
+    case .points(let points) where points.count == 2:
         buffer = """
         .twoPoints(
-        \(printPointNormal(pn1)),
-        \(printPointNormal(pn2))
+        \(printPointNormal(points[0])),
+        \(printPointNormal(points[1]))
+        )
+        """
+
+    case .points(let points):
+        buffer = """
+        .points(
+        \(points.map(printPointNormal).joined(separator: ",\n"))
         )
         """
     }

Sources/TestCommons/P5Printer.swift

@@ -122,9 +122,10 @@ public class P5Printer {
         case .singlePoint(let pn):
             add(pn, style: style, file: file, line: line)
 
-        case let .twoPoints(p1, p2):
-            add(p1, style: style, file: file, line: line)
-            add(p2, style: style, file: file, line: line)
+        case .points(let points):
+            for point in points {
+                add(point, style: style, file: file, line: line)
+            }
         }
     }