Question

我编写了一段python代码，可以将网格序列化为ascii或二进制PLY文件。我可以在MeshLab中打开生成的ascii文件就好了。生成的二进制文件会导致MeshLab崩溃（但它只是段错误）。我也无法在Blender中打开文件。我很难理解为什么MeshLab崩溃，因为据我所知，我坚持我写的标题。这是违规代码：

def write_ply(mesh, filename, binary=True):
    """
    Output the mesh object as an ASCII .ply file, or as a little endian binary file.
    """
    header = "comment This file was generated by the SurfacePy library\n"
    header += "element vertex {0}\n".format(len(mesh.vertices))
    header += "property float x\nproperty float y\nproperty float z\n"
    header += "element face {0}\n".format(len(mesh.triangles))
    header += "property list uchar int vertex_indices\n"
    header += "end_header\n"
    with open(filename, 'wb') as file:
        if binary==True:
            file.write(__pack_string("ply\nformat binary_little_endian 1.0\n"))
        else:
            file.write(__pack_string("ply\nformat ascii 1.0\n"))
        file.write(__pack_string(header))
        if binary==True:
            for vert in mesh.vertices:
                file.write(struct.pack('<fff', vert.x, vert.y, vert.z))
            for tri in mesh.triangles:
                file.write(struct.pack('<Biii', ord('3'), tri.i1, tri.i3, tri.i2))
        else:
            for vert in mesh.vertices:
                file.write(__pack_string("{0}\n".format(vert)))
            for tri in mesh.triangles:
                file.write(__pack_string("3 {0} {1} {2}\n".format(tri.i1, tri.i3, tri.i2)))


def __pack_string(str):
    """
    Returns a bytes object of a string, in little-endian format.
    """
    chars = [c.encode('utf-8') for c in str]
    fmt = "<{0}".format(''.join(['c' for i in range(0, len(chars))]))
    return __pack(fmt, chars)



def __pack(fmt, args):
    return struct.pack(fmt, *args)

我是否错误地写了字节？

Answer 1

这个实际上很难解决。我将属性列表计数类型存储为uchar，但整数应该直接写入uchar，而不是像我一样从char转换。

所以我应该struct.pack('<Biii', 3, ...而不是struct.pack('<Biii', ord('3'), ...

我写的二进制PLY文件导致meshlab崩溃

1 个答案: