;; The first three lines of this file were inserted by DrRacket. They record
metadata
;; about the language level of this file in a form that our tools can easily
process.
#reader(lib "htdp-beginner-reader.ss" "lang")((modname pset-04-starter) (read-case-
sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f
#t none #f () #t)))
;; DO NOT PUT ANYTHING PERSONALLY IDENTIFYING BEYOND YOUR CWL IN THIS FILE.
;; YOUR CWLs WILL BE SUFFICIENT TO IDENTIFY YOU AND, IF YOU HAVE ONE, YOUR
;; PARTNER.
;;
(@assignment pset-03);Do not edit or remove this tag
(@cwl ??? ???) ;Replace ??? with your cwl,
;; ;second ??? is replaced with partner cwl if you have one
;; Bounce a single ball around the screen.
;; IMPORTANT:
;; This problem set will form the basis for problem sets 4 and 5 as well.
;; You are strongly advised to put in the effort to do well on this
;; problem set so that you then have an easier time with problem sets
;; 4 and 5.
;;
;; For this problem set you must complete the design of a world program.
;; The complete program must have the following behaviour:
;; - there is a green background, with a single white ball
;; bouncing around inside that box
;; - when the ball hits the top/right/bottom/left of the box it
;; bounces in the usual way a ball would bounce off of a wall
;; - clicking the mouse replaces the ball with a new ball, at the
;; current mouse position, and with a small random x,y velocity
;;
;; Note that we are giving you significant help in the starter file.
;; There is a complete data design, some complete helper functions, as
;; well as a some wish list entries. You absolutely MUST
;; - not edit any of the complete design elements we give you
;; - complete the wish list entries we give you, and do so in a way
;; that is consistent with the rest of the design we give you
;; - must use the helpers we give you as part of your solution
;;
;; We recommend that you begin by first going through the entire file to
;; understand what is already complete and what you need to complete.
;;
(@problem 1)
(@htdw Ball)
;; ===========================================================================
;; ===========================================================================
;; Data definitions:
(@htdd Ball)
(define-struct ball (x y dx dy))
;; Ball is (make-ball Number Number Number Number)
;; interp. (make-ball x y dx dy) is ball
;; - position x, y in screen coordinates
;; - velocity dx, dy in pixels/tick
(define B1 (make-ball (/ WIDTH 2) (/ HEIGHT 2) 4 -3))
(@dd-template-rules compound)
(define (fn-for-ball b)
(... (ball-x b)
(ball-y b)
(ball-dx b)
(ball-dy b)))
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