From fb91232d104058221776e67df7da5001fed0bc6a Mon Sep 17 00:00:00 2001
From: bubnikv <bubnikv@gmail.com>
Date: Wed, 27 Feb 2019 10:31:53 +0100
Subject: [PATCH] Fix of Model is marked as defective after opening project
 #1863 Fixes SPE-613

---
 src/libslic3r/Format/3mf.cpp | 9 ++++++++-
 src/libslic3r/Format/AMF.cpp | 8 +++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/libslic3r/Format/3mf.cpp b/src/libslic3r/Format/3mf.cpp
index 47f78b360..014e9e606 100644
--- a/src/libslic3r/Format/3mf.cpp
+++ b/src/libslic3r/Format/3mf.cpp
@@ -6,6 +6,8 @@
 
 #include "3mf.hpp"
 
+#include <limits>
+
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/split.hpp>
 #include <boost/algorithm/string/predicate.hpp>
@@ -1749,6 +1751,11 @@ namespace Slic3r {
     bool _3MF_Exporter::_add_model_file_to_archive(mz_zip_archive& archive, Model& model)
     {
         std::stringstream stream;
+        // https://en.cppreference.com/w/cpp/types/numeric_limits/max_digits10
+        // Conversion of a floating-point value to text and back is exact as long as at least max_digits10 were used (9 for float, 17 for double).
+        // It is guaranteed to produce the same floating-point value, even though the intermediate text representation is not exact.
+        // The default value of std::stream precision is 6 digits only!
+		stream << std::defaultfloat << std::setprecision(std::numeric_limits<float>::max_digits10);
         stream << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
         stream << "<" << MODEL_TAG << " unit=\"millimeter\" xml:lang=\"en-US\" xmlns=\"http://schemas.microsoft.com/3dmanufacturing/core/2015/02\" xmlns:slic3rpe=\"http://schemas.slic3r.org/3mf/2017/06\">\n";
         stream << " <" << METADATA_TAG << " name=\"" << SLIC3RPE_3MF_VERSION << "\">" << VERSION_3MF << "</" << METADATA_TAG << ">\n";
@@ -1864,7 +1871,7 @@ namespace Slic3r {
             for (int i = 0; i < stl.stats.shared_vertices; ++i)
             {
                 stream << "     <" << VERTEX_TAG << " ";
-                Vec3d v = matrix * stl.v_shared[i].cast<double>();
+                Vec3f v = (matrix * stl.v_shared[i].cast<double>()).cast<float>();
                 stream << "x=\"" << v(0) << "\" ";
                 stream << "y=\"" << v(1) << "\" ";
                 stream << "z=\"" << v(2) << "\" />\n";
diff --git a/src/libslic3r/Format/AMF.cpp b/src/libslic3r/Format/AMF.cpp
index 2f5284db9..d7b41362c 100644
--- a/src/libslic3r/Format/AMF.cpp
+++ b/src/libslic3r/Format/AMF.cpp
@@ -1,3 +1,4 @@
+#include <limits>
 #include <string.h>
 #include <map>
 #include <string>
@@ -856,6 +857,11 @@ bool store_amf(const char *path, Model *model, const DynamicPrintConfig *config)
         return false;
 
     std::stringstream stream;
+    // https://en.cppreference.com/w/cpp/types/numeric_limits/max_digits10
+    // Conversion of a floating-point value to text and back is exact as long as at least max_digits10 were used (9 for float, 17 for double).
+    // It is guaranteed to produce the same floating-point value, even though the intermediate text representation is not exact.
+    // The default value of std::stream precision is 6 digits only!
+    stream << std::defaultfloat << std::setprecision(std::numeric_limits<float>::max_digits10);
     stream << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
     stream << "<amf unit=\"millimeter\">\n";
     stream << "<metadata type=\"cad\">Slic3r " << SLIC3R_VERSION << "</metadata>\n";
@@ -927,7 +933,7 @@ bool store_amf(const char *path, Model *model, const DynamicPrintConfig *config)
             for (size_t i = 0; i < stl.stats.shared_vertices; ++i) {
                 stream << "         <vertex>\n";
                 stream << "           <coordinates>\n";
-                Vec3d v = matrix * stl.v_shared[i].cast<double>();
+                Vec3f v = (matrix * stl.v_shared[i].cast<double>()).cast<float>();
                 stream << "             <x>" << v(0) << "</x>\n";
                 stream << "             <y>" << v(1) << "</y>\n";
                 stream << "             <z>" << v(2) << "</z>\n";