public void GetData <T>(
int offsetInBytes,
T[] data,
int startIndex,
int elementCount
) where T : struct
{
if (data == null)
{
throw new ArgumentNullException("data");
}
if (data.Length < (startIndex + elementCount))
{
throw new InvalidOperationException("The array specified in the data parameter is not the correct size for the amount of data requested.");
}
if (BufferUsage == BufferUsage.WriteOnly)
{
throw new NotSupportedException(
"This IndexBuffer was created with a usage type of BufferUsage.WriteOnly. " +
"Calling GetData on a resource that was created with BufferUsage.WriteOnly is not supported."
);
}
int elementSizeInBytes = Marshal.SizeOf(typeof(T));
GCHandle handle = GCHandle.Alloc(data, GCHandleType.Pinned);
FNA3D.FNA3D_GetIndexBufferData(
GraphicsDevice.GLDevice,
buffer,
offsetInBytes,
handle.AddrOfPinnedObject() + (startIndex * elementSizeInBytes),
elementCount * elementSizeInBytes
);
handle.Free();
}