/// <summary> /// Removes a blob from the GLB at the given BufferView /// Updates accessors and images to have correct new bufferview index /// This function can invalidate BufferViewId's returned by previous function /// </summary> /// <param name="glb">The glb to remove from</param> /// <param name="bufferViewId">The buffer to remove</param> public static void RemoveBinaryData(GLBObject glb, BufferViewId bufferViewId) { if (glb == null) { throw new ArgumentNullException(nameof(glb)); } if (bufferViewId == null) { throw new ArgumentNullException(nameof(bufferViewId)); } BufferView bufferViewToRemove = bufferViewId.Value; int id = bufferViewId.Id; if (bufferViewToRemove.ByteOffset + bufferViewToRemove.ByteLength == glb.BinaryChunkInfo.Length) { uint bufferViewLengthAsUint = bufferViewToRemove.ByteLength; glb.SetFileLength(glb.Header.FileLength - bufferViewLengthAsUint); glb.SetBinaryChunkLength(glb.BinaryChunkInfo.Length - bufferViewLengthAsUint); if (glb.BinaryChunkInfo.Length == 0) { glb.Root.Buffers.RemoveAt(0); foreach (BufferView bufferView in glb.Root.BufferViews) // other buffers may still exist, and their index has now changed { --bufferView.Buffer.Id; } glb.SetFileLength(glb.Header.FileLength - GLTFParser.CHUNK_HEADER_SIZE); } else { glb.Root.Buffers[0].ByteLength = glb.BinaryChunkInfo.Length; // write binary chunk header WriteChunkHeader(glb.Stream, glb.BinaryChunkInfo); } // trim the end glb.Stream.SetLength(glb.Header.FileLength); // write glb header WriteHeader(glb.Stream, glb.Header, glb.StreamStartPosition); } glb.Root.BufferViews.RemoveAt(id); if (glb.Root.Accessors != null) { foreach (Accessor accessor in glb.Root.Accessors) // shift over all accessors { if (accessor.BufferView != null && accessor.BufferView.Id >= id) { --accessor.BufferView.Id; } if (accessor.Sparse != null) { if (accessor.Sparse.Indices?.BufferView.Id >= id) { --accessor.Sparse.Indices.BufferView.Id; } if (accessor.Sparse.Values?.BufferView.Id >= id) { --accessor.Sparse.Values.BufferView.Id; } } } } if (glb.Root.Images != null) { foreach (GLTFImage image in glb.Root.Images) { if (image.BufferView != null && image.BufferView.Id >= id) { --image.BufferView.Id; } } } }
private static BufferViewId _AddBinaryData(GLBObject glb, Stream binaryData, bool createBufferView, long streamStartPosition, string bufferViewName = null) { binaryData.Position = streamStartPosition; // Append new binary chunk to end uint blobLengthAsUInt = CalculateAlignment((uint)(binaryData.Length - streamStartPosition), 4); uint newBinaryBufferSize = glb.BinaryChunkInfo.Length + blobLengthAsUInt; uint newGLBSize = glb.Header.FileLength + blobLengthAsUInt; uint blobWritePosition = glb.Header.FileLength; // there was an existing file that had no binary chunk info previously if (glb.BinaryChunkInfo.Length == 0) { newGLBSize += GLTFParser.CHUNK_HEADER_SIZE; blobWritePosition += GLTFParser.CHUNK_HEADER_SIZE; glb.SetBinaryChunkStartPosition(glb.Header.FileLength); // if 0, then appends chunk info at the end } glb.Stream.SetLength(glb.Header.FileLength + blobLengthAsUInt); glb.Stream.Position = blobWritePosition; // assuming the end of the file is the end of the binary chunk binaryData.CopyTo(glb.Stream); // make sure this doesn't supersize it glb.SetFileLength(newGLBSize); glb.SetBinaryChunkLength(newBinaryBufferSize); // write glb header past magic number WriteHeader(glb.Stream, glb.Header, glb.StreamStartPosition); WriteChunkHeader(glb.Stream, glb.BinaryChunkInfo); if (createBufferView) { // Add a new BufferView to the GLTFRoot BufferView bufferView = new BufferView { Buffer = new BufferId { Id = 0, Root = glb.Root }, ByteLength = blobLengthAsUInt, // figure out whether glb size is wrong or if documentation is unclear ByteOffset = glb.BinaryChunkInfo.Length - blobLengthAsUInt, Name = bufferViewName }; if (glb.Root.BufferViews == null) { glb.Root.BufferViews = new List <BufferView>(); } glb.Root.BufferViews.Add(bufferView); return(new BufferViewId { Id = glb.Root.BufferViews.Count - 1, Root = glb.Root }); } return(null); }