How big of a performance hit comes from using get_surfacepixel?
The manual says that it shouldn't be used often because it is slow. Unfortunately, with the lighting engine I've created, I have literally no other way of knowing if the player is in shadows or not without get_surfacepixel, which I need to know so that I can draw the player's shadow on the same surface as the rest of the shadows in order for them to merge properly. At max, only 4 get_surfacepixel's ever have to run (two for the player, two for the player's potential follower), but they're running continuously in the draw event in every single room that the player object is in. So, most rooms.
I haven't personally noticed any performance hits or hiccups, but I also have a really, really good PC, so I need to know how big a hit the average player will get from it.