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;;;; examples/09-ghoulspree.lisp
(defpackage #:ww.examples/9
(:use #:cl)
(:export #:start)
(:import-from #:defclass-std #:defclass/std))
(in-package #:ww.examples/9)
;;; CLASSES
(defclass/std ghoulspree (ww::application)
((ghouls-per-click :std 20)
(collision-on-p :std t)
(gravity-on-p :std nil)))
(defclass/std ghoul (ww:image)
((dx dy dr :std)))
;;; UTILITY FUNCTIONS
(defun make-ghoul (x y)
(make-instance 'ghoul :texture (ww:get-asset "Fezghoul.png")
:x x :y y
:dr (random-velocity 0.2)
:dx (random-velocity 4)
:dy (random-velocity 4)))
(defun out-of-bounds-p (ghoul)
(not
(and
(< -50 (ww:x ghoul) 850)
(< -50 (ww:y ghoul) 650))))
(defun random-velocity (&optional (size 1.0))
(* size (if (zerop (random 2))
(random 1.0)
(* -1 (random 1.0)))))
(defun advance-pos (thing)
(with-accessors ((dr dr) (dx dx) (dy dy) (x ww::x) (y ww::y) (r ww::rotation)) thing
(incf x dx)
(incf y dy)
(incf r dr)))
(defun clamp (lo val hi)
"Returns VAL if (< LO VAL HI), otherwise returns LO or HI depending
on which boundary VAL is outside of."
(max lo (min val hi)))
(defun sign (x)
(if (zerop x) 0
(/ x (abs x))))
(defmacro with-pairs ((a b) vector &rest body)
(alexandria:with-gensyms (idxa idxb vec)
`(loop
with ,vec = ,vector
for ,idxa from 0 to (- (length ,vec) 2)
for ,a = (aref ,vec ,idxa) do
(loop for ,idxb from (1+ ,idxa) to (1- (length ,vec))
for ,b = (aref ,vec ,idxb) do
(progn ,@body)))))
(defun handle-collision (g1 g2 &optional (friction 0.99))
(with-slots ((dx1 dx) (dy1 dy) (dr1 dr)) g1
(with-slots ((dx2 dx) (dy2 dy) (dr2 dr)) g2
(let ((tdx (* friction dx1))
(tdy (* friction dy1))
(tdr (* friction dr1)))
(setf dx1 (* friction dx2)
dy1 (* friction dy2)
dr1 (* friction dr2)
dx2 tdx
dy2 tdy
dr2 tdr)))))
(defun apply-gravity-to (thing acc)
(with-slots (dx dy) thing
(decf dy acc)))
(ww:defhandler moveghouls
(ww:on-perframe (app)
;; first handle collisions
(when (collision-on-p app)
(with-pairs
(g1 g2) (ww::application-scene app)
(when (ww:units-intersect-p g1 g2)
(handle-collision g1 g2 1.0)
;; need a "bounce"
(advance-pos g1)
(advance-pos g1)
(advance-pos g2)
(advance-pos g2))))
;; then update positions and remove the out of bounds
(let ((gravity
(gravity-on-p app))
(accelleration
(/ 9.8 (ww:fps app))))
(loop for ghoul across (ww::application-scene app)
do (advance-pos ghoul)
when gravity
do (apply-gravity-to ghoul accelleration)
when (out-of-bounds-p ghoul)
;; note, it is generally a BadIdea™ to delete
;; something from an array that you are iterating
;; over. It only works as expected here b/c of
;; implicit knowledge about the imlementation of the
;; scene container. A safer way in most cases would be
;; to `collect ghoul into drop-list` and then deleted
;; all the collected ghouls in a `finally` clause.
do (ww:drop-unit ghoul)))))
(defun random-sign ()
(if (zerop (random 2)) -1 1))
(defun random-between (lo hi)
(+ lo (random (- hi lo))))
(ww:defhandler add-ghouls
(ww:on-mousedown (app x y)
(loop repeat (ghouls-per-click app)
for rx = (random 800); (+ x (* (random-sign) (random-between 30 60)))
for ry = (random 600); (+ y (* (random-sign) (random-between 30 60)))
do (ww:add-unit (make-ghoul rx ry)))
(format t "~a ghouls on screen~%"
(length (ww::application-scene app )))))
(ww:defhandler toggle-collision
(ww:on-keydown (app scancode)
(case scancode
(:scancode-c
(format t "collision: ~a~%"
(setf (collision-on-p app)
(not (collision-on-p app)))))
(:scancode-g
(format t "gravity: ~a~%"
(setf (gravity-on-p app)
(not (gravity-on-p app))))))))
(defmethod ww::boot ((app ghoulspree))
"Adds the intro text and sets up the start button handler."
(format t "Click to add ~a ghouls to the screen.~%" (ghouls-per-click app))
(format t "Press c to toggle collision handling.~%")
(format t "Press g to toggle gravity.~%")
(ww:add-handler app #'add-ghouls)
(ww:add-handler app #'moveghouls)
(ww:add-handler app #'toggle-collision))
(defun start (&optional (scale 1.0))
(ww::start
(make-instance
'ghoulspree
:fps 60
:width (round (* 800 scale))
:height (round (* 600 scale))
:scale scale
:refocus-on-mousedown-p nil
:title "Click to add ghouls"
:asset-root
(merge-pathnames
"examples/"
(asdf:system-source-directory :wheelwork)))))
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