public (int VertexOffset, int VertexCount) AddVertices(ReadOnlySpan <Byte> vertexData, VertexDeclaration vertexFormat)
{
var count = vertexData.Length / vertexFormat.VertexStride;
if (count == 0)
{
return(_VertexCount, 0);
}
if (_VertexCount == 0)
{
_VertexElements = vertexFormat.GetVertexElements();
_VertexStride = vertexFormat.VertexStride;
}
else
{
var thisVD = new VertexDeclaration(_VertexStride, _VertexElements);
if (!thisVD.Equals(vertexFormat))
{
throw new ArgumentException(nameof(vertexFormat));
}
}
vertexData = vertexData.Slice(0, count * _VertexStride);
int offset = _VertexCount;
Array.Resize(ref _VertexData, (offset + count) * _VertexStride);
vertexData.CopyTo(_VertexData.AsSpan().Slice(offset * _VertexStride));
_VertexCount += count;
return(offset, count);
}