public static void DrawIndexedPrimitives(this GraphicsDevice GraphicsDevice, VertexBuffer vb, IndexBuffer ib, VertexDeclaration decl)
{
GraphicsDevice.SetVertexBuffer(vb, decl, ib);
GraphicsDevice.DrawIndexedPrimitives(vb.GetVertexBufferCount(), ib.GetIndexBufferPrimitiveCount());
}