Is this oriented towards educational use, or is it a more general-purpose library?
y On Tue, Nov 27, 2012 at 10:51 PM, Jay McCarthy <jay.mccar...@gmail.com> wrote: > And if you don't want to write your own... > > I have a Planet package or github repo for almost everything... > > (old) slow functional physics in Racket --- > https://github.com/jeapostrophe/pfp/blob/master/example.ss > > (old) interface to fast Chipmunk library --- > https://github.com/jeapostrophe/chipmunk/ > > my current system in pure Racket with a broad phase / narrow phase > distinction: https://github.com/get-bonus/get-bonus/tree/master/gb/physics > > Personally, I think you should use this opportunity to teach your kid > the Pythagorean Theorem, like the Boostrap curriculum teaches: > http://www.bootstrapworld.org/materials/ > > Jay > > On Tue, Nov 27, 2012 at 8:37 PM, Stephen Bloch <bl...@adelphi.edu> wrote: >> >> On Nov 27, 2012, at 8:56 PM, Yaron Minsky wrote: >> >>> I've been weaning my son off of Scratch in favor of Racket, and trying >>> to get him to write interactive games using universe.ss and image.ss. >>> I'm wondering if anyone has suggestions for how to do things like >>> collision detection. image.ss has these nice first-class images, but >>> I don't see a good way of querying two images to see if they overlap. >> >> Right, and the question doesn't even make sense at the "image" level because >> images don't have locations. >> >> One "purist" answer would be to write your own collision detection, based on >> whatever data type you're using for your model. If it has two fields >> "player-posn" and "monster-posn", you can do a distance formula calculation >> to find out how close those two points are to one another, and decide >> whether it's close enough to constitute a "collision". If it has a list of >> posns (or structs that contain posns), you can do that for each pair of >> elements in the list. >> >> But that's a pain, however much one might learn from the process. If you >> just want to get a game with collision detection up and running, it would be >> nice if the image and/or universe libraries provided some support. An easy >> example would be rects-intersect?: call it on the bounding rectangles of >> your two translated images, and it tells you whether they intersect. (A >> student could write that easily enough, and use it henceforth.) Spiffier, >> in case you wanted to treat irregularly-shaped objects properly, would be a >> function images-intersect? that takes in two translated images and tells >> whether there is a pixel location for which both have nonzero alpha channels. >> >> How do you represent a "translated image"? It could be an image and a posn, >> or it could be just an image formed by place-image onto an all-transparent >> background. >> >>> Has anyone else had luck in doing this? universe has a nice >>> programming model, but I've found it challenging to find simple ways >>> of doing the kinds of things that Scratch makes easy. >> >> And vice versa, of course: there are lots of things that are easy in >> universe, but very difficult in Scratch. >> >> >> Stephen Bloch >> sbl...@adelphi.edu >> >> >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users > > > > -- > Jay McCarthy <j...@cs.byu.edu> > Assistant Professor / Brigham Young University > http://faculty.cs.byu.edu/~jay > > "The glory of God is Intelligence" - D&C 93 ____________________ Racket Users list: http://lists.racket-lang.org/users
