Resolved Issues With Corrupted STL Files When Exporting to stdout (op…

…enscad#5470) --------- Co-authored-by: Marius Kintel <[email protected]>
schiele · Dec 4, 2024 · c190dac · c190dac
1 parent fc3aa54
commit c190dac
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Showing 3 changed files with 35 additions and 19 deletions.
diff --git a/src/io/export_stl.cc b/src/io/export_stl.cc
@@ -293,29 +293,40 @@ void export_stl(const std::shared_ptr<const Geometry>& geom, std::ostream& outpu
 {
   // FIXME: In lazy union mode, should we export multiple solids?
   if (binary) {
+    std::ostringstream buffer; // Using a memory buffer
     char header[80] = "OpenSCAD Model\n";
-    output.write(header, sizeof(header));
-    char tmp_triangle_count[4] = {0, 0, 0, 0}; // We must fill this in below.
-    output.write(tmp_triangle_count, 4);
-  } else {
-    setlocale(LC_NUMERIC, "C"); // Ensure radix is . (not ,) in output
-    output << "solid OpenSCAD_Model\n";
-  }
+    buffer.write(header, sizeof(header));
+
+  // Placeholder for triangle count
+    uint32_t triangle_count = 0;
+    char tmp_triangle_count[4] = {0, 0, 0, 0};
+    buffer.write(tmp_triangle_count, 4);
+
+    // Writing triangles and counting them
+    triangle_count = append_stl(geom, buffer, binary);
+
+  if (triangle_count > 4294967295) {
+    LOG(message_group::Export_Error, "Triangle count exceeded 4294967295, so the STL file is not valid");
+    }
 
-  uint64_t triangle_count = append_stl(geom, output, binary);
+  // Updating the triangle count in the buffer
+    char triangle_count_bytes[4] = {
+        static_cast<char>(triangle_count & 0xff),
+        static_cast<char>((triangle_count >> 8) & 0xff),
+        static_cast<char>((triangle_count >> 16) & 0xff),
+        static_cast<char>((triangle_count >> 24) & 0xff)};
+    buffer.seekp(80, std::ios_base::beg);
+    buffer.write(triangle_count_bytes, 4);
+
+    // Flushing the buffer to the output stream
+    output << buffer.str();
 
-  if (binary) {
-    // Fill in triangle count.
-    output.seekp(80, std::ios_base::beg);
-    output.put(triangle_count & 0xff);
-    output.put((triangle_count >> 8) & 0xff);
-    output.put((triangle_count >> 16) & 0xff);
-    output.put((triangle_count >> 24) & 0xff);
-    if (triangle_count > 4294967295) {
-      LOG(message_group::Export_Error, "Triangle count exceeded 4294967295, so the stl file is not valid");
-    }
   } else {
+    // ASCII mode: Write directly to the output stream
+    setlocale(LC_NUMERIC, "C"); // Ensure radix is . (not ,) in output
+    output << "solid OpenSCAD_Model\n";
+    uint64_t triangle_count = append_stl(geom, output, binary);
     output << "endsolid OpenSCAD_Model\n";
-    setlocale(LC_NUMERIC, ""); // Set default locale
+    setlocale(LC_NUMERIC, ""); // Restore default locale
   }
 }
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
@@ -1137,9 +1137,14 @@ ${TEST_SCAD_DIR}/misc/rotate_extrude-hole.scad
 
 # Export tests (compare actually exported files)
 add_cmdline_test(stlexport              EXPERIMENTAL OPENSCAD SUFFIX stl FILES ${EXPORT_STL_TEST_FILES} ARGS --enable=predictible-output --render)
+add_cmdline_test(stlexport-stdout       EXPERIMENTAL OPENSCAD SUFFIX stl FILES ${EXPORT_STL_TEST_FILES} STDIO EXPECTEDDIR stlexport ARGS --enable=predictible-output --render --export-format asciistl)
 if (ENABLE_MANIFOLD)
 add_cmdline_test(manifold-stlexport     EXPERIMENTAL OPENSCAD SUFFIX stl FILES ${EXPORT_STL_TEST_FILES} EXPECTEDDIR stlexport ARGS --enable=predictible-output --backend=manifold --render)
 endif()
+
+add_cmdline_test(binstlexport           EXPERIMENTAL OPENSCAD SUFFIX stl FILES ${EXPORT_STL_TEST_FILES} ARGS --enable=predictible-output --render --export-format binstl)
+add_cmdline_test(binstlexport-stdout    EXPERIMENTAL OPENSCAD SUFFIX stl FILES ${EXPORT_STL_TEST_FILES} STDIO EXPECTEDDIR binstlexport ARGS --enable=predictible-output --render --export-format binstl)
+
 add_cmdline_test(objexport              EXPERIMENTAL OPENSCAD SUFFIX obj FILES ${EXPORT_OBJ_TEST_FILES} ARGS --render --enable=predictible-output)
 if (LIB3MF_FOUND)
 add_cmdline_test(3mfexport              EXPERIMENTAL OPENSCAD SUFFIX 3mf FILES ${EXPORT_3MF_TEST_FILES} ARGS --enable=predictible-output)

diff --git a/tests/regression/binstlexport/stl-export-expected.stl b/tests/regression/binstlexport/stl-export-expected.stl