for both VertexBuffer<T> and VertexBufferSlice<T>, T is Sized type and method write() takes &self and data: &T;
That means that you are able to modify only 1 T at a time with this method.

Another way would be to use map() method and then for result of that method use deref_mut() but it returns &mut T, so you can modify only 1 T at a thime with this method.

So the only solution is to in loop, make slice (VertexBufferSlice) of size of 1 T from VertexBuffer for each vertex I want to modify and write() to it, right?
No more convinient ways to do that?

btw how do i add tags?
#question