Utility/OBJParser: Add saving

Former-commit-id: f991f0a66a82a68659f14a7ba887b49a2690f5a7 [formerly e4c96019484ad436048d001bd307ac549dfc615a]
Former-commit-id: 946f9e5f99ff46c26741f1877391506b23602517

include/Nazara/Utility/Formats/OBJParser.hpp

@@ -58,6 +58,8 @@ namespace Nz
 
 			bool Parse(Stream& stream, std::size_t reservedVertexCount = 100);
 
+			bool Save(Stream& stream) const;
+
 		private:
 			bool Advance(bool required = true);
 			template<typename T> void Emit(const T& text) const;

include/Nazara/Utility/Formats/OBJParser.inl

@@ -63,12 +63,37 @@ namespace Nz
 		return m_texCoords.size();
 	}
 
+	template<typename T>
+	void OBJParser::Emit(const T& text) const
+	{
+		m_outputStream << text;
+		if (m_outputStream.GetBufferSize() > 1024 * 1024)
+			Flush();
+	}
+
+	inline void OBJParser::EmitLine() const
+	{
+		Emit('\n');
+	}
+
+	template<typename T>
+	void OBJParser::EmitLine(const T& line) const
+	{
+		Emit(line);
+		Emit('\n');
+	}
 
 	inline void OBJParser::Error(const String& message)
 	{
 		NazaraError(message + " at line #" + String::Number(m_lineCount));
 	}
 
+	inline void OBJParser::Flush() const
+	{
+		m_currentStream->Write(m_outputStream);
+		m_outputStream.Clear();
+	}
+
 	inline void OBJParser::Warning(const String& message)
 	{
 		NazaraWarning(message + " at line #" + String::Number(m_lineCount));

src/Nazara/Utility/Formats/OBJParser.cpp

@@ -363,6 +363,148 @@ namespace Nz
 		return true;
 	}
 
+	bool OBJParser::Save(Stream& stream) const
+	{
+		m_currentStream = &stream;
+
+		// Force stream in text mode, reset it at the end
+		Nz::CallOnExit resetTextMode;
+		if ((stream.GetStreamOptions() & StreamOption_Text) == 0)
+		{
+			stream.EnableTextMode(true);
+
+			resetTextMode.Reset([&stream] ()
+			{
+				stream.EnableTextMode(false);
+			});
+		}
+
+		m_outputStream.Clear();
+
+		EmitLine("# Exported by Nazara Engine");
+
+		if (!m_mtlLib.IsEmpty())
+		{
+			Emit("mtlib ");
+			EmitLine(m_mtlLib);
+			EmitLine();
+		}
+
+		Emit("# position count: ");
+		EmitLine(m_positions.size());
+
+		for (const Nz::Vector4f& position : m_positions)
+		{
+			Emit("v ");
+			Emit(position.x);
+			Emit(' ');
+			Emit(position.y);
+			if (!NumberEquals(position.z, 0.f) || !NumberEquals(position.w, 1.f))
+			{
+				Emit(' ');
+				Emit(position.z);
+
+				if (!NumberEquals(position.w, 1.f))
+				{
+					Emit(' ');
+					Emit(position.w);
+				}
+			}
+			EmitLine();
+		}
+		EmitLine();
+
+		Emit("# normal count: ");
+		EmitLine(m_normals.size());
+
+		for (const Nz::Vector3f& normal : m_normals)
+		{
+			Emit("vn ");
+			Emit(normal.x);
+			Emit(' ');
+			Emit(normal.y);
+			Emit(' ');
+			Emit(normal.y);
+			EmitLine();
+		}
+		EmitLine();
+
+		Emit("# texcoords count: ");
+		EmitLine(m_texCoords.size());
+
+		for (const Nz::Vector3f& uvw : m_texCoords)
+		{
+			Emit("vt ");
+			Emit(uvw.x);
+			Emit(' ');
+			Emit(uvw.y);
+			if (NumberEquals(uvw.z, 0.f))
+			{
+				Emit(' ');
+				Emit(uvw.z);
+			}
+			EmitLine();
+		}
+		EmitLine();
+
+		std::unordered_map<std::size_t /* mesh */, std::vector<std::size_t> /* meshes*/> meshesByMaterials;
+		std::size_t meshIndex = 0;
+		for (const Mesh& mesh : m_meshes)
+			meshesByMaterials[mesh.material].push_back(meshIndex++);
+
+		for (auto& pair : meshesByMaterials)
+		{
+			Emit("usemtl ");
+			EmitLine(m_materials[pair.first]);
+			Emit("# groups count: ");
+			EmitLine(pair.second.size());
+			EmitLine();
+
+			for (std::size_t meshIndex : pair.second)
+			{
+				const Mesh& mesh = m_meshes[meshIndex];
+
+				Emit("g ");
+				EmitLine(mesh.name);
+				EmitLine();
+				
+				Emit("# face count: ");
+				EmitLine(mesh.faces.size());
+				Emit("# vertex count: ");
+				EmitLine(mesh.vertices.size());
+				
+				for (const Face& face : mesh.faces)
+				{
+					Emit('f');
+					for (std::size_t i = 0; i < face.vertexCount; ++i)
+					{
+						Emit(' ');
+						const FaceVertex& faceVertex = mesh.vertices[face.firstVertex + i];
+						Emit(faceVertex.position);
+						if (faceVertex.texCoord != 0 || faceVertex.normal != 0)
+						{
+							Emit('/');
+							if (faceVertex.texCoord != 0)
+								Emit(faceVertex.texCoord);
+
+							if (faceVertex.normal != 0)
+							{
+								Emit('/');
+								Emit(faceVertex.normal);
+							}
+						}
+					}
+					EmitLine();
+				}
+			}
+			EmitLine();
+		}
+
+		Flush();
+
+		return true;
+	}
+
 	bool OBJParser::Advance(bool required)
 	{
 		if (!m_keepLastLine)