106 lines
2.9 KiB
C#

using System;
using System.IO;
using System.Runtime.InteropServices;
using Unity.Collections;
using Unity.Collections.LowLevel.Unsafe;
namespace UniGLTF
{
/// <summary>
/// for exporter
/// </summary>
public class ArrayByteBuffer
{
public string Uri
{
get;
private set;
}
Byte[] m_bytes;
int m_used;
public ArrayByteBuffer(Byte[] bytes = null)
{
Uri = "";
m_bytes = bytes;
}
public glTFBufferView Extend<T>(NativeArray<T> array, glBufferTarget target = default) where T : struct
{
return Extend(new ArraySegment<T>(array.ToArray()), target);
}
public glTFBufferView Extend<T>(ArraySegment<T> array, glBufferTarget target = default) where T : struct
{
using (var pin = Pin.Create(array))
{
var elementSize = Marshal.SizeOf(typeof(T));
var view = Extend(pin.Ptr, array.Count * elementSize, elementSize, target);
return view;
}
}
public glTFBufferView Extend(IntPtr p, int bytesLength, int stride, glBufferTarget target)
{
var tmp = m_bytes;
// alignment
var padding = m_used % stride == 0 ? 0 : stride - m_used % stride;
if (m_bytes == null || m_used + padding + bytesLength > m_bytes.Length)
{
// recreate buffer
m_bytes = new Byte[m_used + padding + bytesLength];
if (m_used > 0)
{
Buffer.BlockCopy(tmp, 0, m_bytes, 0, m_used);
}
}
if (m_used + padding + bytesLength > m_bytes.Length)
{
throw new ArgumentOutOfRangeException();
}
Marshal.Copy(p, m_bytes, m_used + padding, bytesLength);
var result = new glTFBufferView
{
buffer = 0,
byteLength = bytesLength,
byteOffset = m_used + padding,
byteStride = stride,
target = target,
};
m_used = m_used + padding + bytesLength;
return result;
}
public void ExtendCapacity(int capacity)
{
if (m_bytes != null && capacity < m_bytes.Length)
{
return;
}
var newBuffer = new byte[capacity];
if (m_bytes != null && m_used > 0)
{
Buffer.BlockCopy(m_bytes, 0, newBuffer, 0, m_used);
}
m_bytes = newBuffer;
}
public ArraySegment<byte> Bytes
{
get
{
if (m_bytes == null)
{
return new ArraySegment<byte>();
}
return new ArraySegment<byte>(m_bytes, 0, m_used);
}
}
}
}