I wish to get the screenspace coordinates corresponding to the vertex of a Model. For doing this, I need to have access to the MVP matrix which I shall multiply with the vertex positions to get the Clip Space Coordinates.
I did exactly that in that minimal example GitHub - abernier/vertex-journey: The complete journey of a vertex, going from model coordinates to screen coordinates where I start with local cube-space coordinates, up to screen-space coordinates.
Just check the README it should be self-explanatory.
I also recently published a Change of basis - memo to help me keep my mind clear about the different THREE spaces and how to “jump” from/to one to another.