tried to add assimp (spoilers, it did not go well, so hey! now we have separate fiels now.)

src/ThirdParty/assimp/code/AssetLib/3MF/D3MFOpcPackage.h

@@ -0,0 +1,84 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2025, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+#ifndef D3MFOPCPACKAGE_H
+#define D3MFOPCPACKAGE_H
+
+#include <assimp/IOSystem.hpp>
+#include <memory>
+#include <string>
+
+struct aiTexture;
+
+namespace Assimp {
+
+class ZipArchiveIOSystem;
+
+namespace D3MF {
+
+struct OpcPackageRelationship {
+    std::string id;
+    std::string type;
+    std::string target;
+};
+
+class D3MFOpcPackage {
+public:
+    D3MFOpcPackage( IOSystem* pIOHandler, const std::string& file );
+    ~D3MFOpcPackage();
+    IOStream* RootStream() const;
+    bool validate();
+    const std::vector<aiTexture*> &GetEmbeddedTextures() const;
+
+protected:
+    std::string ReadPackageRootRelationship(IOStream* stream);
+    void LoadEmbeddedTextures(IOStream *fileStream, const std::string &filename);
+
+private:
+    IOStream* mRootStream;
+    ZipArchiveIOSystem *mZipArchive;
+    std::vector<aiTexture *> mEmbeddedTextures;
+};
+
+} // namespace D3MF
+} // namespace Assimp
+
+#endif // D3MFOPCPACKAGE_H