I'm studying "game physics" programming, and in this article, at page 14, I don't understand how is the author right.
... if the sphere does indeed collide with the inside of the triangle then a collision against a vertex or edge must happen “further down the velocity” so to speak. So if we can quickly detect collision against the inside then we can skip the more expensive “sweep test” against the vertices and edges.
How is this true? There could be a scenario as I drew, where the sphere collides only with the inside of a triangle, without touching a vertex or an edge "further down the velocity". Am I delusional?
Imagine the sphere is moving downward. It must collide only with the inside of the triangle without touching vertices or edges. What did the author mean?
I'm asking this question here because last time I asked something similar in stackoverflow they closed my thread.
Edit: Weird - in the summary in page 18, it says:
• First we checked if we had a collision inside the triangle. If this was the case we could skip the sweep because it must take place before any vertex or edge collisions.
Isn't it the absolute opposite than what he says earlier?
As Rahul wrote, "a collision against a vertex or edge" seems to be intended to mean "any collision against a vertex or edge". This interpretation fits well with the rest of the text; in particular it makes sense of the immediately following sentence.