將osg::Geometry轉(zhuǎn)換為FMeshDescription，通過(guò)FMeshDescription即可構(gòu)建UStaticMesh，下面這段代碼主要是為了轉(zhuǎn)換傾斜攝影的osgb數(shù)據(jù)，但是傾斜攝影數(shù)據(jù)中本身不攜帶法線數(shù)據(jù)，也不需要計(jì)算法線，因此如果要轉(zhuǎn)換其他攜帶或需要計(jì)算法線的osg::Geometry的數(shù)據(jù)，請(qǐng)另行將法線信息補(bǔ)充到FMeshDescription中文章來(lái)源地址http://www.zghlxwxcb.cn/news/detail-859001.html

FMeshDescription ConvertOsgGeometryToMeshDescription(osg::ref_ptr<osg::Geometry> InGeometry)
{
	FMeshDescription result;
	//頂點(diǎn)
	osg::MixinVector<osg::Vec3f>* vertices = dynamic_cast<osg::MixinVector<osg::Vec3f>*>(InGeometry->getVertexArray());
	if (!vertices)
		return result;
	//紋理坐標(biāo)
	osg::MixinVector<osg::Vec2f>* texCoords = dynamic_cast<osg::MixinVector<osg::Vec2f>*>(InGeometry->getTexCoordArray(0));
	assert(vertices->size() == texCoords->size());

	//法線，傾斜攝影數(shù)據(jù)沒(méi)有法線，其實(shí)不需要
	osg::MixinVector<osg::Vec3f>* normals = dynamic_cast<osg::MixinVector<osg::Vec3f>*>(InGeometry->getNormalArray());
	//索引
	osg::MixinVector<unsigned int>* indices = dynamic_cast<osg::MixinVector<unsigned int>*>(InGeometry->getPrimitiveSet(0));
	if (!indices)
		return result;
	assert(indices->size() / 3 == 0);

	FStaticMeshAttributes attributes(result);
	//注冊(cè)默認(rèn)的靜態(tài)模型屬性
	attributes.Register();

	//FMeshDescriptionBuilder用于設(shè)置頂點(diǎn)、法線、UV坐標(biāo)等信息
	FMeshDescriptionBuilder meshDescBuilder;
	meshDescBuilder.SetMeshDescription(&result);
	//允許使用多邊形組
	meshDescBuilder.EnablePolyGroups();
	//設(shè)置UV坐標(biāo)的級(jí)數(shù)為1
	meshDescBuilder.SetNumUVLayers(1);
	FPolygonGroupID GroupId = meshDescBuilder.AppendPolygonGroup();

	const uint32 vertexCount = vertices->size();
	TArray<FVertexID> vertexIDs;
	vertexIDs.SetNum(vertices->size());
	const float unit = 100.0;
	// 定義一個(gè)Lambda表達(dá)式，用于將OSG坐標(biāo)轉(zhuǎn)換為UE坐標(biāo)
	auto ConvertOSGToUE = [&unit](const osg::Vec3f& OSGCoordinate) -> FVector
		{
			float X = OSGCoordinate.x() * unit;
			float Y = -OSGCoordinate.y() * unit; 
			float Z = OSGCoordinate.z() * unit; 

			return FVector(X, Y, Z);
		};
	for (uint32 i = 0; i < vertexCount; ++i) {
		const osg::Vec3f vertex = vertices->at(i);
		vertexIDs[i] = meshDescBuilder.AppendVertex(ConvertOSGToUE(vertex));
	}

	const uint32 indiceCount = indices->size();
	assert(indiceCount / 3 == 0);
	const uint32 triangleCount = indiceCount / 3;
	for (uint32 i = 0; i < triangleCount; ++i) {
		const uint32 indice1 = indices->at(i * 3);
		const FVertexInstanceID vertexInstanceId1 = meshDescBuilder.AppendInstance(vertexIDs[indice1]);
		const osg::Vec2f texCoord1 = texCoords->at(indice1);
		meshDescBuilder.SetInstanceUV(vertexInstanceId1, FVector2D(texCoord1.x(), 1 - texCoord1.y()), 0);

		const uint32 indice2 = indices->at(i * 3 + 1);
		const FVertexInstanceID vertexInstanceId2 = meshDescBuilder.AppendInstance(vertexIDs[indice2]);
		const osg::Vec2f texCoord2 = texCoords->at(indice2);
		meshDescBuilder.SetInstanceUV(vertexInstanceId2, FVector2D(texCoord2.x(), 1 - texCoord2.y()), 0);

		const uint32 indice3 = indices->at(i * 3 + 2);
		const FVertexInstanceID vertexInstanceId3 = meshDescBuilder.AppendInstance(vertexIDs[indice3]);
		const osg::Vec2f texCoord3 = texCoords->at(indice3);
		meshDescBuilder.SetInstanceUV(vertexInstanceId3, FVector2D(texCoord3.x(), 1 - texCoord3.y()), 0);

		meshDescBuilder.AppendTriangle(vertexInstanceId1, vertexInstanceId2, vertexInstanceId3, GroupId);

	}

	//FStaticMeshOperations::ComputeTriangleTangentsAndNormals(result);//傾斜攝影數(shù)據(jù)沒(méi)有法線，不必計(jì)算
	return result;
}

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