编辑:所以在与Assimp dev进行短暂接触之后,我被指向了导入过程 . 当我从其他人手中接过代码时,我认为没有看到那部分:
using (var importer = new AssimpContext())
{
scene = importer.ImportFile(file, PostProcessSteps.Triangulate | PostProcessSteps.FlipUVs | PostProcessSteps.JoinIdenticalVertices);
}
FlipUV完全按照它所说的做,它在y轴上翻转,因此原点现在是左上角 . 所以现在我能够获得具有适当UV但仍然是镜像网格的模型 . 设置具有缩放x = -1的父对象将其翻转回正常并使其看起来很好,但我想这并不意味着 . 所以我一直在寻找 .
看图,有两种起重机型号 . 左边的那个在运行时通过序列化和重建加载,而右边的那个是原始的,只是拖动到场景 . 序列化发生在Assimp库中 .
地板碰巧首先被创建,似乎得到了正确的紫外线 Map . 而其他项目出错了uv map . 虽然我正在打印uv Map 的值,但它们似乎与原始 Map 相匹配 .
这是序列化的方法,这是来自Assimp的Mesh类,而不是Unity Mesh类,应用程序序列化是在UWP中构建的Windows应用程序:
private static void SerializeMeshes(BinaryWriter writer, IEnumerable<Mesh> meshes)
{
foreach (Mesh mesh in meshes)
{
ICollection<int> triangles = MeshLoadTriangles(mesh);
MeshSerializeHeader(writer, mesh.Name, mesh.VertexCount, triangles.Count, mesh.MaterialIndex);
MeshSerializeVertices(writer, mesh.Vertices);
MeshSerializeUVCoordinate(writer, mesh.TextureCoordinateChannels);
MeshSerializeTriangleIndices(writer, triangles);
}
}
private static void MeshSerializeUVCoordinate(BinaryWriter writer, List<Vector3D>[] textureCoordinateChannels)
{
// get first channel and serialize to writer. Discard z channel
// This is Vector3D since happening outside Unity
List<Vector3D> list = textureCoordinateChannels[0];
foreach (Vector3D v in list)
{
float x = v.X;
float y = v.Y;
writer.Write(x);
writer.Write(y);
}
}
private static void MeshSerializeVertices(BinaryWriter writer, IEnumerable<Vector3D> vertices)
{
foreach (Vector3D vertex in vertices)
{
Vector3D temp = vertex;
writer.Write(temp.X);
writer.Write(temp.Y);
writer.Write(temp.Z);
}
}
private static void MeshSerializeTriangleIndices(BinaryWriter writer, IEnumerable<int> triangleIndices)
{
foreach (int index in triangleIndices) { writer.Write(index); }
}
这是反转过程:
private static void DeserializeMeshes(BinaryReader reader, SceneGraph scene)
{
MeshData[] meshes = new MeshData[scene.meshCount];
for (int i = 0; i < scene.meshCount; i++)
{
meshes[i] = new MeshData();
MeshReadHeader(reader, meshes[i]);
MeshReadVertices(reader, meshes[i]);
MeshReadUVCoordinate(reader, meshes[i]);
MeshReadTriangleIndices(reader, meshes[i]);
}
scene.meshes = meshes as IEnumerable<MeshData>;
}
private static void MeshReadUVCoordinate(BinaryReader reader, MeshData meshData)
{
bool hasUv = reader.ReadBoolean();
if(hasUv == false) { return; }
Vector2[] uvs = new Vector2[meshData.vertexCount];
for (int i = 0; i < uvs.Length; i++)
{
uvs[i] = new Vector2();
uvs[i].x = reader.ReadSingle();
uvs[i].y = reader.ReadSingle();
}
meshData.uvs = uvs;
}
private static void MeshReadHeader(BinaryReader reader, MeshData meshData)
{
meshData.name = reader.ReadString();
meshData.vertexCount = reader.ReadInt32();
meshData.triangleCount = reader.ReadInt32();
meshData.materialIndex = reader.ReadInt32();
}
private static void MeshReadVertices(BinaryReader reader, MeshData meshData)
{
Vector3[] vertices = new Vector3[meshData.vertexCount];
for (int i = 0; i < vertices.Length; i++)
{
vertices[i] = new Vector3();
vertices[i].x = reader.ReadSingle();
vertices[i].y = reader.ReadSingle();
vertices[i].z = reader.ReadSingle();
}
meshData.vertices = vertices;
}
private static void MeshReadTriangleIndices(BinaryReader reader, MeshData meshData)
{
int[] triangleIndices = new int[meshData.triangleCount];
for (int i = 0; i < triangleIndices.Length; i++)
{
triangleIndices[i] = reader.ReadInt32();
}
meshData.triangles = triangleIndices;
}
MeshData只是一个临时容器,带有来自fbx的反序列化值 . 然后,创建网格:
private static Mesh[] CreateMeshes(SceneGraph scene)
{
Mesh[] meshes = new Mesh[scene.meshCount];
int index = 0;
foreach (MeshData meshData in scene.meshes)
{
meshes[index] = new Mesh();
Vector3[] vec = meshData.vertices;
meshes[index].vertices = vec;
meshes[index].triangles = meshData.triangles;
meshes[index].uv = meshData.uvs;
meshes[index].normals = meshData.normals;
meshes[index].RecalculateNormals();
index++;
}
return meshes;
}
我没有在代码中看到任何导致这种行为的原因,我会说如果值是错误的话,它会完全搞砸网格 .
我可以看到我所拥有的fbx文件使用四边形而不是三角形来进行索引 .
可能是Assimp不顺利吗?
1 回答
我没有从Assimp以适当的方式解决问题 .
我们使用的基本解决方案是对在对象变换中翻转的轴进行负向缩放 .
更合适的解决方案是将所有顶点馈送到Unity侧的矩阵,以便正确地解析顶点的位置 .
获取顶点列表
foreach顶点乘以旋转矩阵
将数组指定给网格
使用网格渲染