From c520f4d9de42b65153ca60bec2a3ebddf3f348a6 Mon Sep 17 00:00:00 2001
From: alemuntoni <muntoni.alessandro@gmail.com>
Date: Fri, 18 Jun 2021 12:45:17 +0200
Subject: [PATCH] first draft nexus exporter

---
 src/external/nexus                   |   2 +-
 src/meshlabplugins/io_nxs/io_nxs.cpp | 134 +++++++++++++++++++++++++++
 2 files changed, 135 insertions(+), 1 deletion(-)

diff --git a/src/external/nexus b/src/external/nexus
index 8f507ed59..f15c1a0b2 160000
--- a/src/external/nexus
+++ b/src/external/nexus
@@ -1 +1 @@
-Subproject commit 8f507ed591c9edaeb0e31a9b8950ed64cfade507
+Subproject commit f15c1a0b24e402a61622395cf46da44e5291278c
diff --git a/src/meshlabplugins/io_nxs/io_nxs.cpp b/src/meshlabplugins/io_nxs/io_nxs.cpp
index be2f1cbc4..2a3f4c4db 100644
--- a/src/meshlabplugins/io_nxs/io_nxs.cpp
+++ b/src/meshlabplugins/io_nxs/io_nxs.cpp
@@ -24,6 +24,12 @@
 #include <common/ml_document/mesh_model.h>
 #include "io_nxs.h"
 
+#include <QTextStream>
+#include <nxsbuild/nexusbuilder.h>
+#include <nxsbuild/meshstream.h>
+#include <nxsbuild/vcgloader.h>
+#include <nxsbuild/kdtree.h>
+
 QString IONXSPlugin::pluginName() const
 {
 	return "IONXS";
@@ -79,7 +85,135 @@ void IONXSPlugin::save(
 		vcg::CallBackPos*)
 {
 	if (fileFormat.toUpper() == "NXS"){
+		int node_size = 1<<15;
+		int top_node_size = 4096;
+		float vertex_quantization = 0.0f;   //optionally quantize vertices position.
+		int tex_quality(92);                //default jpg texture quality
+		//QString decimation("quadric");      //simplification method
+		int ram_buffer(2000);               //Mb of ram to use
+		int n_threads = 4;
+		float scaling(0.5);                 //simplification ratio
+		int skiplevels = 0;
+		vcg::Point3d origin(0, 0, 0);
+		bool center = false;
 
+
+		bool point_cloud = false;
+		bool normals = false;
+		bool no_normals = false;
+		bool colors = false;
+		bool no_colors = false;
+		bool no_texcoords = false;
+		bool useOrigTex = false;
+		bool create_pow_two_tex = false;
+		bool deepzoom = false;
+
+		QVariant adaptive(0.333f);
+
+		Stream* stream = nullptr;
+		VcgLoader<CMeshO>* loader = nullptr;
+		KDTree* tree = nullptr;
+		try {
+			quint64 max_memory = (1<<20)*(uint64_t)ram_buffer/4; //hack 4 is actually an estimate...
+			std::string input = "mesh";
+			if (point_cloud) {
+				input = "pointcloud";
+				stream = new StreamCloud("cache_stream");
+			}
+			else
+				stream = new StreamSoup("cache_stream");
+			stream->setVertexQuantization(vertex_quantization);
+			stream->setMaxMemory(max_memory);
+			if(center) {
+				stream->origin = m.cm.bbox.Center();
+			} else
+				stream->origin = origin;
+
+			vcg::Point3d &o = stream->origin;
+			if(o[0] != 0.0 || o[1] != 0.0 || o[2] != 0.0) {
+				int lastPoint = fileName.lastIndexOf(".");
+				QString ref = fileName.left(lastPoint) + ".js";
+				QFile file(ref);
+				if(!file.open(QFile::ReadWrite)) {
+					throw MLException("Could not save reference file: " + ref);
+				}
+				QTextStream stream(&file);
+				stream.setRealNumberPrecision(12);
+				stream << "{ \"origin\": [" << o[0] << ", " << o[1] << ", " << o[2] << "] }\n";
+			}
+
+			loader = new VcgLoader<CMeshO>;
+			//todo
+			bool has_colors = false, has_normals  = false, has_textures  = false;
+			loader->load(&m.cm, has_colors, has_normals, has_textures);
+			stream->load(loader);
+
+			quint32 components = 0;
+			if(!point_cloud) components |= NexusBuilder::FACES;
+
+			if((!no_normals && (!point_cloud || has_normals)) || normals) {
+				components |= NexusBuilder::NORMALS;
+				cout << "Normals enabled\n";
+			}
+			if((has_colors  && !no_colors ) || colors ) {
+				components |= NexusBuilder::COLORS;
+				cout << "Colors enabled\n";
+			}
+			if(has_textures && !no_texcoords) {
+				components |= NexusBuilder::TEXTURES;
+				cout << "Textures enabled\n";
+			}
+
+			//WORKAROUND to save loading textures not needed
+			if(!(components & NexusBuilder::TEXTURES)) {
+				stream->textures.clear();
+			}
+
+			NexusBuilder builder(components);
+			builder.skipSimplifyLevels = skiplevels;
+			builder.setMaxMemory(max_memory);
+			builder.n_threads = n_threads;
+			builder.setScaling(scaling);
+			builder.useNodeTex = !useOrigTex;
+			builder.createPowTwoTex = create_pow_two_tex;
+			if(deepzoom)
+				builder.header.signature.flags |= nx::Signature::Flags::DEEPZOOM;
+			builder.tex_quality = tex_quality;
+			bool success = builder.initAtlas(stream->textures);
+			if(!success) {
+				throw MLException("Fail");
+			}
+			if(point_cloud)
+				tree = new KDTreeCloud("cache_tree", adaptive.toFloat());
+			else
+				tree = new KDTreeSoup("cache_tree", adaptive.toFloat());
+
+			tree->setMaxMemory((1<<20)*(uint64_t)ram_buffer/2);
+			KDTreeSoup *treesoup = dynamic_cast<KDTreeSoup *>(tree);
+			if(treesoup)
+				treesoup->setTrianglesPerBlock(node_size);
+
+			KDTreeCloud *treecloud = dynamic_cast<KDTreeCloud *>(tree);
+			if(treecloud)
+				treecloud->setTrianglesPerBlock(node_size);
+
+			builder.create(tree, stream,  top_node_size);
+			builder.save(fileName);
+			delete tree;
+			delete loader;
+			delete stream;
+		}
+		catch(QString error) {
+			delete tree;
+			delete loader;
+			delete stream;
+			throw MLException("Fatal error: " + error);
+		} catch(const char *error) {
+			delete tree;
+			delete loader;
+			delete stream;
+			throw MLException("Fatal error: " + QString(error));
+		}
 	}
 	else {
 		wrongSaveFormat(fileFormat);