summaryrefslogtreecommitdiff
path: root/examples/quadtree.scm
blob: 31b8138c7e5bb87f1a4564c0a96c68a9de406dc7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
(use-modules (chickadee)
             (chickadee data quadtree)
             (chickadee math)
             (chickadee math matrix)
             (chickadee math rect)
             (chickadee math vector)
             (chickadee graphics color)
             (chickadee graphics font)
             (chickadee graphics path)
             (chickadee graphics sprite)
             (chickadee graphics texture)
             (chickadee scripting)
             (ice-9 format)
             (ice-9 match)
             (srfi srfi-1)
             (srfi srfi-9)
             (statprof))

(define-record-type <actor>
  (make-actor position velocity bounding-box)
  actor?
  (position actor-position)
  (velocity actor-velocity)
  (bounding-box actor-bounding-box))

(define texture #f)
(define batch #f)
(define start-time 0.0)
(define avg-frame-time 16)
(define actor-count 250)
(define actors
  (list-tabulate actor-count
                 (lambda (n)
                   (let ((x (* (random:uniform) 624.0))
                         (y (* (random:uniform) 464.0)))
                     (make-actor (vec2 x y)
                                 (vec2 (* (- (random:uniform) 0.5) 3.0)
                                       (* (- (random:uniform) 0.5) 3.0))
                                 (rect x y 16.0 16.0))))))
(define quadtree (make-quadtree (make-rect 0.0 0.0 640.0 480.0) #:max-size 4 #:max-depth 4))
(define canvas (make-empty-canvas))
(define paused? #f)
(define matrix (make-identity-matrix4))
(define stats-text-pos (vec2 4.0 464.0))
(define stats-text #f)

(for-each (lambda (actor)
            (quadtree-insert! quadtree (actor-bounding-box actor) actor))
          actors)

(define (quadtree-nodes quadtree)
  (if (quadtree-leaf? quadtree)
      (list quadtree)
      (cons quadtree
            (append (quadtree-nodes (quadtree-q1 quadtree))
                    (quadtree-nodes (quadtree-q2 quadtree))
                    (quadtree-nodes (quadtree-q3 quadtree))
                    (quadtree-nodes (quadtree-q4 quadtree))))))

(define (paint-canvas)
  (let ((painter (with-style ((stroke-color tango-scarlet-red))
                   (apply superimpose
                          (map (lambda (node)
                                 (let ((rect (quadtree-bounds node)))
                                   (stroke
                                    (rectangle (vec2 (rect-x rect)
                                                     (rect-y rect))
                                               (rect-width rect)
                                               (rect-height rect)))))
                               (quadtree-nodes quadtree))))))
    (set-canvas-painter! canvas painter)))

(define (stats-message)
  (format #f "  actors: ~d  fps: ~1,2f"
          actor-count (/ 1.0 avg-frame-time)))

(define (load)
  (set! *random-state* (random-state-from-platform))
  (set! texture (load-image "images/shot.png"))
  (set! batch (make-sprite-batch texture #:capacity actor-count))
  (paint-canvas)
  (script
   (forever
    (set! stats-text (stats-message))
    (sleep 60))))

(define (draw alpha)
  (sprite-batch-clear! batch)
  (for-each (lambda (actor)
              (sprite-batch-add* batch (actor-bounding-box actor) matrix))
            actors)
  (draw-canvas canvas)
  (draw-sprite-batch batch)
  (draw-text stats-text stats-text-pos #:color black)
  (let ((current-time (elapsed-time)))
    (set! avg-frame-time
          (+ (* (- current-time start-time) 0.1)
             (* avg-frame-time 0.9)))
    (set! start-time current-time)))

(define (clamp-x x)
  (clamp 0.0 624.0 x))

(define (clamp-y y)
  (clamp 0.0 464.0 y))

(define (update dt)
  (update-agenda 1)
  (unless paused?
    ;; Move
    (for-each (lambda (actor)
                (let ((p (actor-position actor))
                      (v (actor-velocity actor))
                      (r (actor-bounding-box actor)))
                  (quadtree-delete! quadtree r actor)
                  ;; Move by velocity, clamping to the edge of the
                  ;; window.
                  (set-vec2-x! p (clamp-x (+ (vec2-x p) (vec2-x v))))
                  (set-vec2-y! p (clamp-y (+ (vec2-y p) (vec2-y v))))
                  (set-rect-x! r (vec2-x p))
                  (set-rect-y! r (vec2-y p))
                  ;; Check for and resolve collision.
                  (quadtree-find
                   quadtree r
                   (lambda (other)
                     ;; Calculate overlap.
                     (let* ((ro (actor-bounding-box other))
                            (xo (max (- (min (rect-right r) (rect-right ro))
                                        (max (rect-left r) (rect-left ro)))
                                     0.0))
                            (yo (max (- (min (rect-top r) (rect-top ro))
                                        (max (rect-bottom r) (rect-bottom ro)))
                                     0.0)))
                       (if (or (= xo 0.0) (= yo 0.0))
                           #f          ; no collision
                           (let ((vo (actor-velocity other)))
                             ;; Resolve the collsion with the least
                             ;; possible movement.  Bounce the
                             ;; colliding actors off of each other by
                             ;; reversing the x or y component of the
                             ;; velocity vectors.
                             (if (< xo yo)
                                 (let* ((xdiff (- (rect-x r) (rect-x ro)))
                                        (xsign (/ xdiff (abs xdiff))))
                                   (set-vec2-x! p (clamp-x (+ (vec2-x p) (* xo xsign))))
                                   (set-vec2-x! v (* (vec2-x v) -1.0))
                                   (set-vec2-x! vo (* (vec2-x vo) -1.0)))
                                 (let* ((ydiff (- (rect-y r) (rect-y ro)))
                                        (ysign (/ ydiff (abs ydiff))))
                                   (set-vec2-y! p (clamp-y (+ (vec2-y p) (* yo ysign))))
                                   (set-vec2-y! v (* (vec2-y v) -1.0))
                                   (set-vec2-y! vo (* (vec2-y vo) -1.0))))
                             (set-rect-x! r (vec2-x p))
                             (set-rect-y! r (vec2-y p))
                             #t)))))
                  ;; Bounce off the window edges.
                  (when (or (= (vec2-x p) 0.0)
                            (= (vec2-x p) 624.0))
                    (set-vec2-x! v (* (vec2-x v) -1.0)))
                  (when (or (= (vec2-y p) 0.0)
                            (= (vec2-y p) 464.0))
                    (set-vec2-y! v (* (vec2-y v) -1.0)))
                  (quadtree-insert! quadtree r actor)))
              actors)
    (paint-canvas)))

(define (key-press key modifiers repeat?)
  (case key
    ((q)
     (abort-game))
    ((space)
     (set! paused? (not paused?)))))

(run-game #:window-title "quadtree"
          #:load load
          #:draw draw
          #:update update
          #:key-press key-press)