From 667b466ca7c71a5bde5be59ec29ecce8cbddfafb Mon Sep 17 00:00:00 2001
From: Michael Carleton <micycle1@hotmail.co.uk>
Date: Fri, 14 Feb 2025 14:16:40 +0000
Subject: [PATCH] assorted

---
 CHANGELOG.md                                  |  1 +
 src/main/java/micycle/pgs/PGS_Conversion.java |  2 +-
 src/main/java/micycle/pgs/PGS_PointSet.java   | 20 ++++++++++++++++++-
 .../java/micycle/pgs/PGS_ShapePredicates.java | 14 ++++++++++++-
 .../java/micycle/pgs/commons/ChaikinCut.java  |  4 ++--
 5 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8a5dde73..170cc09a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * `maximumInscribedTriangle()` to `PGS_Optimisation`. Finds an approximate largest area triangle (of arbitrary orientation) contained within a polygon.
 * `closestPoint()` to `PGS_Optimisation`. Finds the closest point in a collection of points to a specified point.
 * `distanceTree()` to `PGS_Contour`. Generates a tree structure representing the shortest paths from a start point to all other vertices in a mesh.
+* `vertexCount()` to `PGS_ShapePredicates`. Returns the total number of vertices that make up a shape.
 
 ### Changes
 * Optimised `PGS_CirclePacking.tangencyPack()`. It's now around 1.5-2x faster and has higher precision.
diff --git a/src/main/java/micycle/pgs/PGS_Conversion.java b/src/main/java/micycle/pgs/PGS_Conversion.java
index 109e47e3..aead2bb2 100644
--- a/src/main/java/micycle/pgs/PGS_Conversion.java
+++ b/src/main/java/micycle/pgs/PGS_Conversion.java
@@ -1504,7 +1504,7 @@ public static PShape fromArray(double[][] shape, boolean close) {
 	/**
 	 * Flattens a collection of PShapes into a single GROUP PShape which has the
 	 * input shapes as its children. If the collection contains only one shape, it
-	 * is directly returned.
+	 * is returned directly as a non-GROUP shape.
 	 *
 	 * @since 1.2.0
 	 * @see #flatten(PShape...)
diff --git a/src/main/java/micycle/pgs/PGS_PointSet.java b/src/main/java/micycle/pgs/PGS_PointSet.java
index 76b48372..f7cae32a 100644
--- a/src/main/java/micycle/pgs/PGS_PointSet.java
+++ b/src/main/java/micycle/pgs/PGS_PointSet.java
@@ -43,9 +43,27 @@
  * Generation of random sets of 2D points having a variety of different
  * distributions and constraints (and associated functions).
  * 
+ * <p>
+ * <strong>Note on Floating-Point Values and Collisions:</strong>
+ * </p>
+ * <p>
+ * When generating many random points, collisions in coordinate values are
+ * expected due to the limited precision of floating-point numbers. For example:
+ * <ul>
+ * <li>A {@code float} has ~24 bits of precision (23 explicit mantissa bits + 1
+ * implicit leading bit), which allows for ~16.8 million unique values in the
+ * range [0, 1).</li>
+ * <li>When generating a large number of points (e.g., 100,000), the probability
+ * of collisions follows the birthday paradox formula: <code>n² / (2m)</code>,
+ * where <code>n</code> is the number of samples and <code>m</code> is the
+ * number of possible unique values.</li>
+ * <li>For 100,000 points, this results in ~300 expected collisions in the
+ * x-coordinate, even when using a high-quality random number generator.</li>
+ * </ul>
+ * </p>
+ * 
  * @author Michael Carleton
  * @since 1.2.0
- *
  */
 public final class PGS_PointSet {
 
diff --git a/src/main/java/micycle/pgs/PGS_ShapePredicates.java b/src/main/java/micycle/pgs/PGS_ShapePredicates.java
index 39383651..9c3e69c9 100644
--- a/src/main/java/micycle/pgs/PGS_ShapePredicates.java
+++ b/src/main/java/micycle/pgs/PGS_ShapePredicates.java
@@ -453,6 +453,18 @@ public static double convexity(PShape shape) {
 		return g.getArea() / g.convexHull().getArea();
 	}
 
+	/**
+	 * Returns the total number of vertices that make up a shape.
+	 * <p>
+	 * Unlike <code>PShape.getVertexCount()</code> this method properly returns the
+	 * number of vertices in GROUP and primitive shapes.
+	 * 
+	 * @since 2.1
+	 */
+	public static int vertexCount(PShape shape) {
+		return fromPShape(shape).getNumPoints();
+	}
+
 	/**
 	 * Counts the number of holes in a shape.
 	 * <p>
@@ -514,7 +526,7 @@ public static double maximumInteriorAngle(PShape shape) {
 	}
 
 	/**
-	 * Calculates the interior angles of a polygon represented by a {@link PShape}.
+	 * Calculates all interior angles of a polygon represented by a {@link PShape}.
 	 * The method calculates the interior angle at each vertex.
 	 * <p>
 	 * The vertices of the input {@code shape} are assumed to represent a simple
diff --git a/src/main/java/micycle/pgs/commons/ChaikinCut.java b/src/main/java/micycle/pgs/commons/ChaikinCut.java
index 94fe5b09..514e0b2a 100644
--- a/src/main/java/micycle/pgs/commons/ChaikinCut.java
+++ b/src/main/java/micycle/pgs/commons/ChaikinCut.java
@@ -154,14 +154,14 @@ private static ArrayList<PVector> chaikinCut(PVector a, PVector b, float ratio)
 
 	/**
 	 * Determines whether to cut an edge. Returns false for edges with a euclidean
-	 * distance less than 1.0.
+	 * distance less than 0.5.
 	 */
 	private static boolean cut(PVector a, PVector b) {
 		// TODO expand to exclude almost coincident edge pairs
 		final float dx = b.x - a.x;
 		final float dy = b.y - a.y;
 		final float d2 = dx * dx + dy * dy;
-		return d2 > 1;
+		return d2 > 0.5;
 	}
 
 }