public void GetData <T>(
int offsetInBytes,
T[] data,
int startIndex,
int elementCount,
int vertexStride
) where T : struct
{
if (data == null)
{
throw new ArgumentNullException("data");
}
if (data.Length < (startIndex + elementCount))
{
throw new ArgumentOutOfRangeException(
"elementCount",
"This parameter must be a valid index within the array."
);
}
if (BufferUsage == BufferUsage.WriteOnly)
{
throw new NotSupportedException("Calling GetData on a resource that was created with BufferUsage.WriteOnly is not supported.");
}
int elementSizeInBytes = Marshal.SizeOf(typeof(T));
if (vertexStride == 0)
{
vertexStride = elementSizeInBytes;
}
else if (vertexStride < elementSizeInBytes)
{
throw new ArgumentOutOfRangeException(
"vertexStride",
"The vertex stride is too small for the type of data requested. This is not allowed."
);
}
if (elementCount > 1 &&
(elementCount * vertexStride) > (VertexCount * VertexDeclaration.VertexStride))
{
throw new InvalidOperationException("The array is not the correct size for the amount of data requested.");
}
GCHandle handle = GCHandle.Alloc(data, GCHandleType.Pinned);
FNA3D.FNA3D_GetVertexBufferData(
GraphicsDevice.GLDevice,
buffer,
offsetInBytes,
handle.AddrOfPinnedObject() + (startIndex * elementSizeInBytes),
elementCount,
elementSizeInBytes,
vertexStride
);
handle.Free();
}
