From 83122dcfd46d373a989540bc4d680b0ec0ef3129 Mon Sep 17 00:00:00 2001
From: Chandan Yeshwanth <chandan.yeshwanth@tum.de>
Date: Mon, 13 Jun 2022 12:37:09 +0200
Subject: [PATCH] Read the data type for #vertices/face from PLY header, remove
 commented code

---
 include/core-mesh/meshIO.cpp  | 33 ++++++++++-------------------
 include/core-mesh/plyHeader.h | 40 +++++++++++++++++++++++++++++------
 2 files changed, 44 insertions(+), 29 deletions(-)

diff --git a/include/core-mesh/meshIO.cpp b/include/core-mesh/meshIO.cpp
index 7f1cfb3..426560c 100644
--- a/include/core-mesh/meshIO.cpp
+++ b/include/core-mesh/meshIO.cpp
@@ -115,25 +115,22 @@ void MeshIO<FloatType>::loadFromPLY( const std::string& filename, MeshData<Float
 
 		delete [] data;
 
-		size = 1+3*4;	//typically 1 uchar for numVertices per triangle, 3 * int for indices
+		// size of the #vertices/face field, uchar=1, int=4
+		// need to support int field, for eg. PLY files coming from PoissonRecon's SurfaceTrimmer.exe
+		unsigned int verticesPerFaceFieldSize = header.m_properties["verticesPerFace"][0].byteSize;
+		//typically 1 uchar for numVertices per triangle, 3 * int for indices
+		size = verticesPerFaceFieldSize + 3*4;	
 		data = new char[size*header.m_numFaces];
 		file.read(data, size*header.m_numFaces);
-		for (unsigned int i = 0; i < header.m_numFaces; i++) {	
-			mesh.m_FaceIndicesVertices[i][0] = ((int*)&data[i*size+1])[0];
-			mesh.m_FaceIndicesVertices[i][1] = ((int*)&data[i*size+1])[1];
-			mesh.m_FaceIndicesVertices[i][2] = ((int*)&data[i*size+1])[2];
 
-			//mesh.m_FaceIndicesVertices[i].push_back(((int*)&data[i*size+1])[0]);
-			//mesh.m_FaceIndicesVertices[i].push_back(((int*)&data[i*size+1])[1]);
-			//mesh.m_FaceIndicesVertices[i].push_back(((int*)&data[i*size+1])[2]);
+		for (unsigned int i = 0; i < header.m_numFaces; i++) {	
+			// go to the line containing i'th face, then skip the first field (#vertices/face)
+			unsigned int offset = i * size + verticesPerFaceFieldSize;
+			mesh.m_FaceIndicesVertices[i][0] = ((int*)&data[offset])[0];
+			mesh.m_FaceIndicesVertices[i][1] = ((int*)&data[offset])[1];
+			mesh.m_FaceIndicesVertices[i][2] = ((int*)&data[offset])[2];
 		}
 
-		//if (mesh.m_Colors.size() == 0) {
-		//	mesh.m_Colors.resize(header.m_NumVertices);
-		//	for (size_t i = 0; i < mesh.m_Colors.size(); i++) {
-		//		mesh.m_Colors[i] = vec3f(0.5f, 0.5f, 0.5f);
-		//	}
-		//}
 		delete [] data;
 
 	}
@@ -164,14 +161,6 @@ void MeshIO<FloatType>::loadFromPLY( const std::string& filename, MeshData<Float
 			}
 			mesh.m_FaceIndicesVertices.push_back(face);
 		}
-
-		//if (mesh.m_Colors.size() == 0) {
-		//	mesh.m_Colors.resize(header.m_NumVertices);
-		//	for (size_t i = 0; i < mesh.m_Colors.size(); i++) {
-		//		mesh.m_Colors[i] = vec3f(0.5f, 0.5f, 0.5f);
-		//	}
-		//}
-
 	}
 }
 
diff --git a/include/core-mesh/plyHeader.h b/include/core-mesh/plyHeader.h
index 1b78bc2..2b5a3dd 100644
--- a/include/core-mesh/plyHeader.h
+++ b/include/core-mesh/plyHeader.h
@@ -44,6 +44,23 @@ namespace ml {
 			}
 		}
 
+		static unsigned int getByteSizeFromNameType(const std::string& nameType) {
+			/*
+			nameType: double/float/int/uint/char/uchar/short/ushort
+			return: number of bytes occupied by this type
+			*/
+			unsigned int size;
+
+			if (nameType == "double") size = 8;
+			else if (nameType == "float" || nameType == "int" || nameType == "uint") size = 4;
+			else if (nameType == "ushort" || nameType == "short") size = 2;
+			else if (nameType == "uchar" || nameType == "char") size = 1;
+			else {
+				throw MLIB_EXCEPTION("unkown data type");
+			}
+			return size;
+		}
+
 		static void PlyHeaderLine(const std::string& line, PlyHeader& header, std::string& activeElement) {
 
 			std::stringstream ss(line);
@@ -80,15 +97,24 @@ namespace ml {
 						if (p.name == "red") header.m_bHasColors = true;
 					}
 
-					if (p.nameType == "double") p.byteSize = 8;
-					else if (p.nameType == "float" || p.nameType == "int" || p.nameType == "uint") p.byteSize = 4;
-					else if (p.nameType == "ushort" || p.nameType == "short") p.byteSize = 2;
-					else if (p.nameType == "uchar" || p.nameType == "char") p.byteSize = 1;
-					else {
-						throw MLIB_EXCEPTION("unkown data type");
-					}
+					p.byteSize = getByteSizeFromNameType(p.nameType);
 					header.m_properties[activeElement].push_back(p);
 				}
+				// read the line about face indices
+				//eg: property list uchar int vertex_indices
+				//eg: property list int int vertex_indices
+				else if (util::endsWith(line, "vertex_indices") || util::endsWith(line, "vertex_index")) {
+					PlyHeader::PlyPropertyHeader p;
+					std::string ignore;
+					// "list"
+					ss >> ignore;
+					// uchar/int
+					ss >> p.nameType;
+					// create our own name for this
+					p.name = "verticesPerFace";
+					p.byteSize = getByteSizeFromNameType(p.nameType);
+					header.m_properties[p.name].push_back(p);
+				}
 				else {
 					//property belonging to unknown element
 				}