class I3DM:
def __init__(self):
self.batch_table = BatchTable()
self.feature_table = InstanceFeatureTable()
self.gltf_bin = bytearray()
def loadJSONBatch(self, data_in, object_wise=True):
self.batch_table.loadJSONBatch(data_in, object_wise)
def loadJSONInstances(self, i3dm_json, object_wise=True):
self.loadJSONFeatures(i3dm_json, object_wise)
def loadJSONFeatures(self, data_in, object_wise=True):
self.feature_table.loadJSONBatch(data_in, object_wise)
# If embed_gltf is false, gltf_bin is a URI string instead of GLTF data
def writeBinary(self,
gltf_bin,
embed_gltf=True,
num_batches=0,
num_feature_features=0):
self.embed_gltf = embed_gltf
# Add the required field BATCH_LENGTH to the feature table,
# as well as any other required globals
num_batch_features = max(num_batches,
self.batch_table.getNumFeatures())
self.feature_table.addGlobal('BATCH_LENGTH', num_batch_features)
num_feature_features = max(num_feature_features,
self.feature_table.getNumFeatures())
self.feature_table.addGlobal('INSTANCES_LENGTH', num_feature_features)
self.batch_table.finalize()
self.feature_table.finalize()
# Generate the header
output = self.writeHeader(gltf_bin, num_batch_features,
num_feature_features)
# Add the feature table JSON to the output
feature_json = self.feature_table.getFeatureJSON()
output.extend(feature_json)
# Add the feature table binary to the output
feature_bin = self.feature_table.getFeatureBin()
output.extend(feature_bin)
# Add the batch table JSON to the output
batch_json = self.batch_table.getBatchJSON()
output.extend(batch_json)
# Add the batch table binary to the output
batch_bin = self.batch_table.getBatchBin()
output.extend(batch_bin)
# Add the GLTF model body to the output
output.extend(gltf_bin)
return output
# If embed_gltf is false, gltf_bin is a URI string instead of GLTF data
def writeHeader(self, gltf_bin, num_batch_features, num_feature_features):
len_feature_json = len(self.feature_table.getFeatureJSON())
len_feature_bin = len(self.feature_table.getFeatureBin())
len_batch_json = len(self.batch_table.getBatchJSON())
len_batch_bin = len(self.batch_table.getBatchBin())
length = I3DM_HEADER_LEN + \
len_feature_json + len_feature_bin + \
len_batch_json + len_batch_bin + \
len(gltf_bin)
output = bytearray()
output.extend(I3DM_MAGIC)
output.extend(struct.pack('<I', I3DM_VERSION))
output.extend(struct.pack('<I', length))
output.extend(struct.pack('<I', len_feature_json))
output.extend(struct.pack('<I', len_feature_bin))
output.extend(struct.pack('<I', len_batch_json))
output.extend(struct.pack('<I', len_batch_bin))
output.extend(struct.pack('<I', 1 if self.embed_gltf else 0))
# Sanity check
if (len(output) != I3DM_HEADER_LEN):
raise ValueError("Incorrect i3dm header length")
return output
def readBinary(self, data):
self.offset = 0
self.readHeader(data) # What it says on the tin
# Now grab the feature table, batch table, and GLB
self.feature_json = self.unpackString(data, self.len_feature_json)
self.feature_bin = self.unpackString(data, self.len_feature_bin)
self.batch_json = self.unpackString(data, self.len_batch_json)
self.batch_bin = self.unpackString(data, self.len_batch_bin)
self.gltf_bin = self.unpackString(data, self.length - self.offset)
def readHeader(self, data):
self.magic = self.unpack('4s', data)
self.version = self.unpack('<I', data)
if self.magic != I3DM_MAGIC or self.version > I3DM_VERSION:
raise IOError("Unrecognized magic %s or bad version %d" %
(self.magic, self.version))
self.length = self.unpack('<I', data)
self.len_feature_json = self.unpack('<I', data)
self.len_feature_bin = self.unpack('<I', data)
self.len_batch_json = self.unpack('<I', data)
self.len_batch_bin = self.unpack('<I', data)
self.embed_gltf = self.unpack('<I', data)
def getGLTFBin(self):
return self.gltf_bin
def unpackString(self, data, length):
self.offset += length
return data[self.offset - length:self.offset]
def unpack(self, fmt, data):
calc_len = struct.calcsize(fmt)
self.offset += calc_len
return struct.unpack(fmt, data[self.offset - calc_len:self.offset])[0]
class B3DM:
def __init__(self):
self.batch_table = BatchTable()
self.feature_table = FeatureTable()
self.gltf_bin = bytearray()
def loadJSONBatch(self, data_in, object_wise=True):
self.batch_table.loadJSONBatch(data_in, object_wise)
def loadJSONFeature(self, data_in, object_wise=True):
self.feature_table.loadJSONBatch(data_in, object_wise)
def writeBinary(self,
gltf_bin,
num_batch_features=0,
num_feature_features=0):
# Add the required field BATCH_LENGTH to the feature table,
# as well as any other required globals
num_batch_features = max(num_batch_features,
self.batch_table.getNumFeatures())
self.feature_table.addGlobal('BATCH_LENGTH', num_batch_features)
num_feature_features = max(num_feature_features,
self.feature_table.getNumFeatures())
self.batch_table.finalize()
self.feature_table.finalize()
# Generate the header
output = self.writeHeader(gltf_bin, num_batch_features,
num_feature_features)
# Add the feature table JSON to the output
feature_json = self.feature_table.getBatchJSON()
output.extend(feature_json)
# Add the batch table binary to the output
feature_bin = self.feature_table.getBatchBin()
output.extend(feature_bin)
# Add the batch table JSON to the output
batch_json = self.batch_table.getBatchJSON()
output.extend(batch_json)
# Add the batch table binary to the output
batch_bin = self.batch_table.getBatchBin()
output.extend(batch_bin)
# Add the GLTF model body to the output
output.extend(gltf_bin)
return output
def writeHeader(self, gltf_bin, num_feature_features, num_batch_features):
len_feature_json = len(self.feature_table.getBatchJSON())
len_feature_bin = len(self.feature_table.getBatchBin())
len_batch_json = len(self.batch_table.getBatchJSON())
len_batch_bin = len(self.batch_table.getBatchBin())
length = B3DM_HEADER_LEN + \
len_feature_json + len_feature_bin + \
len_batch_json + len_batch_bin + \
len(gltf_bin)
output = bytearray()
output.extend("b3dm")
output.extend(struct.pack('<I', B3DM_VERSION))
output.extend(struct.pack('<I', length))
output.extend(struct.pack('<I', len_feature_json))
output.extend(struct.pack('<I', len_feature_bin))
output.extend(struct.pack('<I', len_batch_json))
output.extend(struct.pack('<I', len_batch_bin))
# Sanity check
if (len(output) != B3DM_HEADER_LEN):
raise ValueError("Incorrect b3dm header length")
return output