import addPipelineExtras from './addPipelineExtras.js'
|
import removeExtensionsUsed from './removeExtensionsUsed.js'
|
import defaultValue from '../../Core/defaultValue.js'
|
import defined from '../../Core/defined.js'
|
import getMagic from '../../Core/getMagic.js'
|
import getStringFromTypedArray from '../../Core/getStringFromTypedArray.js'
|
import RuntimeError from '../../Core/RuntimeError.js'
|
|
var sizeOfUint32 = 4;
|
|
/**
|
* Convert a binary glTF to glTF.
|
*
|
* The returned glTF has pipeline extras included. The embedded binary data is stored in gltf.buffers[0].extras._pipeline.source.
|
*
|
* @param {Buffer} glb The glb data to parse.
|
* @returns {Object} A javascript object containing a glTF asset with pipeline extras included.
|
*
|
* @private
|
*/
|
function parseGlb(glb) {
|
// Check that the magic string is present
|
var magic = getMagic(glb);
|
if (magic !== 'glTF') {
|
throw new RuntimeError('File is not valid binary glTF');
|
}
|
|
var header = readHeader(glb, 0, 5);
|
var version = header[1];
|
if (version !== 1 && version !== 2) {
|
throw new RuntimeError('Binary glTF version is not 1 or 2');
|
}
|
|
if (version === 1) {
|
return parseGlbVersion1(glb, header);
|
}
|
|
return parseGlbVersion2(glb, header);
|
}
|
|
function readHeader(glb, byteOffset, count) {
|
var dataView = new DataView(glb.buffer);
|
var header = new Array(count);
|
for (var i = 0; i < count; ++i) {
|
header[i] = dataView.getUint32(glb.byteOffset + byteOffset + i * sizeOfUint32, true);
|
}
|
return header;
|
}
|
|
function parseGlbVersion1(glb, header) {
|
var length = header[2];
|
var contentLength = header[3];
|
var contentFormat = header[4];
|
|
// Check that the content format is 0, indicating that it is JSON
|
if (contentFormat !== 0) {
|
throw new RuntimeError('Binary glTF scene format is not JSON');
|
}
|
|
var jsonStart = 20;
|
var binaryStart = jsonStart + contentLength;
|
|
var contentString = getStringFromTypedArray(glb, jsonStart, contentLength);
|
var gltf = JSON.parse(contentString);
|
addPipelineExtras(gltf);
|
|
var binaryBuffer = glb.subarray(binaryStart, length);
|
|
var buffers = gltf.buffers;
|
if (defined(buffers) && Object.keys(buffers).length > 0) {
|
// In some older models, the binary glTF buffer is named KHR_binary_glTF
|
var binaryGltfBuffer = defaultValue(buffers.binary_glTF, buffers.KHR_binary_glTF);
|
if (defined(binaryGltfBuffer)) {
|
binaryGltfBuffer.extras._pipeline.source = binaryBuffer;
|
}
|
}
|
// Remove the KHR_binary_glTF extension
|
removeExtensionsUsed(gltf, 'KHR_binary_glTF');
|
return gltf;
|
}
|
|
function parseGlbVersion2(glb, header) {
|
var length = header[2];
|
var byteOffset = 12;
|
var gltf;
|
var binaryBuffer;
|
while (byteOffset < length) {
|
var chunkHeader = readHeader(glb, byteOffset, 2);
|
var chunkLength = chunkHeader[0];
|
var chunkType = chunkHeader[1];
|
byteOffset += 8;
|
var chunkBuffer = glb.subarray(byteOffset, byteOffset + chunkLength);
|
byteOffset += chunkLength;
|
// Load JSON chunk
|
if (chunkType === 0x4E4F534A) {
|
var jsonString = getStringFromTypedArray(chunkBuffer);
|
gltf = JSON.parse(jsonString);
|
addPipelineExtras(gltf);
|
}
|
// Load Binary chunk
|
else if (chunkType === 0x004E4942) {
|
binaryBuffer = chunkBuffer;
|
}
|
}
|
if (defined(gltf) && defined(binaryBuffer)) {
|
var buffers = gltf.buffers;
|
if (defined(buffers) && buffers.length > 0) {
|
var buffer = buffers[0];
|
buffer.extras._pipeline.source = binaryBuffer;
|
}
|
}
|
return gltf;
|
}
|
|
export default parseGlb;
|
