From the Starting Strength book, 2nd edition:
Light warmup sets, done first with the empty bar and then progressively heavier until the work sets are loaded, serve to prepare the movement pattern itself [...]
As a general rule, it is best to start with an empty bar (45 lbs.), determine the work set or sets, and then divide the difference between them into increments. [...]
Most people will need to select three to five warmup sets, depending on the work set weight[...]
The book includes a diagram with examples. The sample bench warm-up is:
45 pounds 2 sets of 5
work sets 175 3x5
So basically, Rippetoe's advice is to warm-up using "ramping", though he doesn't specifically use the term, and he doesn't seem to advocate a warm-up that uses a weight heavier than the work set (as suggested in the article).
Like JFG said, warm-ups don't need to be/should not be complicated.