TriangleSelector: 3MF loading and saving

src/libslic3r/Model.cpp

@@ -1862,6 +1862,64 @@ void FacetsAnnotation::clear()
 
 
 
+// Following function takes data from a triangle and encodes it as string
+// of hexadecimal numbers (one digit per triangle). Used for 3MF export,
+// changing it may break backwards compatibility !!!!!
+std::string FacetsAnnotation::get_triangle_as_string(int triangle_idx) const
+{
+    std::string out;
+
+    auto triangle_it = m_data.find(triangle_idx);
+    if (triangle_it != m_data.end()) {
+        const std::vector<bool>& code = triangle_it->second;
+        int offset = 0;
+        while (offset < int(code.size())) {
+            int next_code = 0;
+            for (int i=3; i>=0; --i) {
+                next_code = next_code << 1;
+                next_code |= int(code[offset + i]);
+            }
+            offset += 4;
+
+            assert(next_code >=0 && next_code <= 15);
+            char digit = next_code < 10 ? next_code + '0' : (next_code-10)+'A';
+            out.insert(out.begin(), digit);
+        }
+    }
+    return out;
+}
+
+
+
+// Recover triangle splitting & state from string of hexadecimal values previously
+// generated by get_triangle_as_string. Used to load from 3MF.
+void FacetsAnnotation::set_triangle_from_string(int triangle_id, const std::string& str)
+{
+    assert(! str.empty());
+    m_data[triangle_id] = std::vector<bool>(); // zero current state or create new
+    std::vector<bool>& code = m_data[triangle_id];
+
+    for (auto it = str.crbegin(); it != str.crend(); ++it) {
+        const char ch = *it;
+        int dec = 0;
+        if (ch >= '0' && ch<='9')
+            dec = int(ch - '0');
+        else if (ch >='A' && ch <= 'F')
+            dec = 10 + int(ch - 'A');
+        else
+            assert(false);
+
+        // Convert to binary and append into code.
+        for (int i=0; i<4; ++i) {
+            code.insert(code.end(), bool(dec & (1 << i)));
+        }
+    }
+
+
+}
+
+
+
 // Test whether the two models contain the same number of ModelObjects with the same set of IDs
 // ordered in the same order. In that case it is not necessary to kill the background processing.
 bool model_object_list_equal(const Model &model_old, const Model &model_new)