How can I get a Buffer of ModelView transformed Vertices?

After a long time reading, I do my first atemp making Decal:

How to project decals - Wolfire Games Blog

We had projected texture,

maybe It still need the “crop process” to procedure a mesh which fit the decal, and not take a whole mesh into a pre-render ( as describe in that article)…


First, I want to get 3D → 2D every vertices of a mesh (transformed, skined by bone…) from world space into viewport space to do the Sutherland-Hodgeman cliping…


Vector3f getScreenCoordinates(Vector3f worldPosition, Vector3f store)

Converts the given position from world space to screen space.

is good but I want the whole mesh at once, how can I?