From 9bb1151dba1a0c10963c5ecb6a7f4561706b613b Mon Sep 17 00:00:00 2001
From: SiboVG <sibo.vangool@hotmail.com>
Date: Fri, 18 Aug 2023 04:01:03 +0200
Subject: [PATCH] Sort export components based on order in rocket This is
 useful if you import the OBJ with "split by groups". In that case, all the
 components are in nice chronological order.

---
 .../export/OBJExporterFactory.java            | 29 +++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/core/src/net/sf/openrocket/file/wavefrontobj/export/OBJExporterFactory.java b/core/src/net/sf/openrocket/file/wavefrontobj/export/OBJExporterFactory.java
index db93b8233..0080fa11c 100644
--- a/core/src/net/sf/openrocket/file/wavefrontobj/export/OBJExporterFactory.java
+++ b/core/src/net/sf/openrocket/file/wavefrontobj/export/OBJExporterFactory.java
@@ -38,6 +38,7 @@ import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -114,8 +115,11 @@ public class OBJExporterFactory {
             }
         }
 
+        // Sort the components according to how they are ordered in the rocket (component tree)
+        Set<RocketComponent> sortedComponents = sortComponents(componentsToExport);
+
         int idx = 1;
-        for (RocketComponent component : componentsToExport) {
+        for (RocketComponent component : sortedComponents) {
             if (component instanceof ComponentAssembly) {
                 continue;
             }
@@ -179,7 +183,7 @@ public class OBJExporterFactory {
             if (options.isExportAppearance()) {
                 String mtlFilePath = FileUtils.removeExtension(filePath) + ".mtl";
                 List<DefaultMtl> mtls = materials.get(obj);
-                try (OutputStream mtlOutputStream = new FileOutputStream(mtlFilePath)) {
+                try (OutputStream mtlOutputStream = new FileOutputStream(mtlFilePath, false)) {
                     DefaultMtlWriter.write(mtls, mtlOutputStream);
                 } catch (IOException e) {
                     throw new RuntimeException(e);
@@ -234,6 +238,27 @@ public class OBJExporterFactory {
         }
     }
 
+    /**
+     * Sort a set of components according to how they are ordered in the rocket (component tree).
+     * @param components components to sort
+     * @return sorted components
+     */
+    private Set<RocketComponent> sortComponents(Set<RocketComponent> components) {
+        Set<RocketComponent> sortedComponents = new LinkedHashSet<>();
+        addChildComponentToList(this.configuration.getRocket(), components, sortedComponents);
+
+        return sortedComponents;
+    }
+
+    private void addChildComponentToList(RocketComponent parent, Set<RocketComponent> components, Set<RocketComponent> sortedComponents) {
+        for (RocketComponent child : parent.getChildren()) {
+            if (components.contains(child)) {
+                sortedComponents.add(child);
+            }
+            addChildComponentToList(child, components, sortedComponents);
+        }
+    }
+
     interface ExporterFactory<T extends RocketComponent> {
         RocketComponentExporter<T> create(DefaultObj obj, FlightConfiguration config, CoordTransform transformer,
                                           T component, String groupName, ObjUtils.LevelOfDetail LOD);