InputOutput.py

import numpy as np
from plyfile import PlyData
from plyfile import PlyElement
from plyfile import make2d

from TriSoupMesh import TriSoupMesh

# Multipurpose mesh reader
def readMesh(filename, filetype=None, output='soup'):

    print('Reading mesh from: ' + filename)

    # TODO implement this
    if(output != 'soup'):
        raise Exception('Mesh types other than soup not yet supported')

    # Attempt to detect the filetype, if necessary
    if not filetype:
        if(filename.endswith('.ply')):
            filetype = 'ply'
        elif(filename.endswith('.obj')):
            filetype = 'obj'
        else:
            raise Exception('Could not detect filetype for input file: ' + filename)


    # Call the appropriate input function
    if filetype == 'ply':
        mesh = readMesh_PLY(filename, output)
    elif filetype == 'obj':
        mesh = readMesh_OBJ(filename, output)
    else:
        raise Exception('No reader for filetype: ' + filetype)

    if(mesh.nVerts == 0):
        raise Exception("ERROR: Loaded mesh has no vertices")

    print('   Loaded mesh with ' + "{:,}".format(mesh.nVerts) + ' vertices and ' + "{:,}".format(mesh.nTris) + ' faces')
    return mesh

# Read a .ply mesh
def readMesh_PLY(filename, output="soup"):

    if(output != 'soup'):
        raise Exception('Mesh types other than soup not yet supported')

    # Read the actual file
    # TODO This takes a long time, maybe try to replace with something faster of my own?
    plydata = PlyData.read(filename)

    # Read vertices
    # If the mesh has more than three columns of vertex data, ignore the later columns
    # (for instance, Stanford Mesh Repo meshes store intensity and confidence here)
    nVerts = plydata['vertex'].count
    verts = np.zeros((nVerts,3))
    verts[:,0] = np.array(plydata['vertex'].data['x'])
    verts[:,1] = np.array(plydata['vertex'].data['y'])
    verts[:,2] = np.array(plydata['vertex'].data['z'])


    # Read faces
    faces = make2d(plydata['face'].data['vertex_indices'])

    # Build a mesh from these vertices and faces
    mesh = TriSoupMesh(verts, faces)

    return mesh


# Read a .ply mesh
# TODO Ignores everything execpt for vertex position and face indices
# TODO Will only process triangular vertices
def readMesh_OBJ(filename, output="soup"):

    if(output != 'soup'):
        raise Exception('Mesh types other than soup not yet supported')

    verts = []
    tris = []

    # Process the file line by line
    lineInd = -1
    for line in open(filename).readlines():
        lineInd += 1
        if line[0] == '#':
            continue

        try:
            items = line.strip('  ','').split()
    
            # Process vertex
            if items[0] == 'v':
                #print items[1:]
                verts.append([float(s) for s in items[1:]])
    
            # Process tex-coord
            elif items[0] == 'vt':
                pass
    
            # Process normal vector
            elif items[0] == 'vn' : #normal vector
                pass
    
            # Process face indices
            elif items[0] == 'f' :
                face = items[1:]
                if len(face) != 3 :
                    print("Line " + str(lineInd) + " is not a triangular face: " + line)
                    continue
    
                # Take index before slash, which is the vertex index (if slash is given).
                # Conversion from 1-based to 0-based indexing happens at end
                tris.append([int(s.split("/")[0]) for s in face])
        except:
            items = line.strip().split()
            if len(items)>0:
                # Process vertex
                if items[0] == 'v':
                    #print items[1:]
                    verts.append([float(s) for s in items[1:]])
        
                # Process tex-coord
                elif items[0] == 'vt':
                    pass
        
                # Process normal vector
                elif items[0] == 'vn' : #normal vector
                    pass
        
                # Process face indices
                elif items[0] == 'f' :
                    face = items[1:]
                    if len(face) != 3 :
                        print("Line " + str(lineInd) + " is not a triangular face: " + line)
                        continue
        
                    # Take index before slash, which is the vertex index (if slash is given).
                    # Conversion from 1-based to 0-based indexing happens at end
                    tris.append([int(s.split("/")[0]) for s in face])
    # Convert to numpy arrays
    verts = np.array(verts)
    tris = np.array(tris)

    # Convert to 0-based indexing
    tris = tris - 1

    # Make a tri-soup mesh
    mesh = TriSoupMesh(verts, tris)

    return mesh