From 06c01debef40c5804783437a6df2b2072ef1b0f7 Mon Sep 17 00:00:00 2001
From: Peter Abeles <peter.abeles@gmail.com>
Date: Thu, 21 Dec 2023 15:42:28 -0800
Subject: [PATCH] PLY - Fixed endian issue when reading/writing polyline

---
 .../src/main/java/boofcv/io/points/impl/PlyCodec.java |  7 ++++++-
 .../test/java/boofcv/io/points/impl/TestPlyCodec.java | 11 +++++++----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/main/boofcv-io/src/main/java/boofcv/io/points/impl/PlyCodec.java b/main/boofcv-io/src/main/java/boofcv/io/points/impl/PlyCodec.java
index 1b483470cf..bddbcf4d7d 100644
--- a/main/boofcv-io/src/main/java/boofcv/io/points/impl/PlyCodec.java
+++ b/main/boofcv-io/src/main/java/boofcv/io/points/impl/PlyCodec.java
@@ -168,6 +168,7 @@ public static void saveBinary( PlyWriter data, ByteOrder order, boolean saveAsFl
 
 		var indexes = new int[100];
 		bytes = ByteBuffer.allocate(1 + indexes.length*4);
+		bytes.order(order);
 		for (int i = 0; i < data.getPolygonCount(); i++) {
 			int size = data.getIndexes(i, indexes);
 			bytes.position(0);
@@ -467,6 +468,7 @@ private static void readCloudBinary( PlyReader output, InputStream reader, List<
 
 		final var polygonLine = new byte[4*10];
 		final ByteBuffer polygonBB = ByteBuffer.wrap(polygonLine);
+		polygonBB.order(order);
 		int[] indexes = new int[100];
 		for (int i = 0; i < triangleCount; i++) {
 			if (1 != reader.read(line, 0, 1))
@@ -482,7 +484,10 @@ private static void readCloudBinary( PlyReader output, InputStream reader, List<
 				throw new IOException("Read unexpected number of bytes. " + found + " vs " + lineLength);
 
 			for (int wordIndex = 0; wordIndex < count; wordIndex++) {
-				indexes[wordIndex] = polygonBB.getInt(wordIndex*4);
+				int foundIndex = polygonBB.getInt(wordIndex*4);
+				if (foundIndex < 0 || foundIndex > vertexCount)
+					throw new IOException("Negative index. word: " + wordIndex + " value: " + foundIndex + " count: " + vertexCount);
+				indexes[wordIndex] = foundIndex;
 			}
 
 			output.addPolygon(indexes, 0, count);
diff --git a/main/boofcv-io/src/test/java/boofcv/io/points/impl/TestPlyCodec.java b/main/boofcv-io/src/test/java/boofcv/io/points/impl/TestPlyCodec.java
index 0d86394aaf..7de91d0665 100644
--- a/main/boofcv-io/src/test/java/boofcv/io/points/impl/TestPlyCodec.java
+++ b/main/boofcv-io/src/test/java/boofcv/io/points/impl/TestPlyCodec.java
@@ -140,11 +140,14 @@ class TestPlyCodec extends BoofStandardJUnit {
 		for (var endian : new ByteOrder[]{ByteOrder.LITTLE_ENDIAN, ByteOrder.BIG_ENDIAN}) {
 			var mesh = new VertexMesh();
 			mesh.offsets.add(0);
-			for (int i = 0; i < 10; i++) {
+			int numVertexes = 10;
+			for (int i = 0; i < numVertexes; i++) {
 				mesh.vertexes.append(i, 2, 3);
-				mesh.indexes.add(i*3);
-				mesh.indexes.add(i*3 + 1);
-				mesh.indexes.add(i*3 + 2);
+
+				// bound indexes to ensure they are in the valid range
+				mesh.indexes.add((i*3)%numVertexes);
+				mesh.indexes.add((i*3 + 1)%numVertexes);
+				mesh.indexes.add((i*3 + 2)%numVertexes);
 				mesh.offsets.add(mesh.indexes.size);
 			}
 			var colors = new DogArray_I32();