Annotation of /sml/trunk/src/eXene/examples/bounce/ball.sml

Parent Directory | Revision Log

---

Revision 2 - (view) (download)

1 :	monnier	2	(* ball.sml
2 :			*
3 :			* COPYRIGHT (c) 1990,1991 by John H. Reppy. See COPYRIGHT file for details.
4 :			*)
5 :
6 :			structure Ball =
7 :			struct
8 :
9 :			datatype ball_msg
10 :			= KILL of Geometry.point
11 :			| REDRAW of (int * Geometry.size)
12 :			| KILL_ALL
13 :
14 :			val updatesPerSec = 10
15 :
16 :			local
17 :			structure MChan = Multicast
18 :			open Geometry BounceDM
19 :
20 :			(* clip a point to keep a ball in the window. If we hit a wall, then
21 :			* we adjust the vector. The clipped point should be computed
22 :			* to lie on the vector, but for now we assume small vectors
23 :			* and just truncate the coordinates. *)
24 :			fun clip (ballRadius, SIZE{wid, ht}) = let
25 :			val maxX = wid - ballRadius and maxY = ht - ballRadius
26 :			fun clipCoord (coord : int, delta, minCoord, maxCoord) =
27 :			if (coord <= minCoord)
28 :			then (minCoord, ~delta)
29 :			else if (coord >= maxCoord)
30 :			then (maxCoord, ~delta)
31 :			else (coord, delta)
32 :			fun clip' (PT{x=x0, y=y0}, PT{x=dx0, y=dy0}) = let
33 :			val (x1, dx1) = clipCoord(x0+dx0, dx0, ballRadius, maxX)
34 :			val (y1, dy1) = clipCoord(y0+dy0, dy0, ballRadius, maxY)
35 :			in
36 :			(PT{x=x1, y=y1}, PT{x=dx1, y=dy1})
37 :			end
38 :			in
39 :			clip'
40 :			end
41 :
42 :			fun mkIconFn win = let
43 :			val ballIcons =
44 :			map (EXeneBase.createTileFromImage (EXeneWin.screenOfWin win))
45 :			Heads.headDataList
46 :			val n = List.length ballIcons
47 :			val ch = CML.channel()
48 :			fun loop i = if (i = n)
49 :			then loop 0
50 :			else (CML.send(ch, List.nth(ballIcons, i)); loop(i+1))
51 :			in
52 :			XDebug.xspawn("newIcon", fn () => loop 0);
53 :			(fn () => CML.recv ch)
54 :			end
55 :
56 :			val delayEvt =
57 :			CML.timeOutEvt(Time.fromMicroseconds(1000000 div updatesPerSec))
58 :			in
59 :
60 :			fun mkBallFn (win, mchan, drawCh) = let
61 :			val newIcon = mkIconFn win
62 :			fun newBall (seqn, pos, vec, sz) = let
63 :			val ballIcon = newIcon()
64 :			val ballRadius = let
65 :			val {sz=SIZE{wid, ...}, ...} = EXeneBase.geomOfTile ballIcon
66 :			in
67 :			wid div 2
68 :			end
69 :			val offset = PT{x=ballRadius, y=ballRadius}
70 :			fun drawBall (n, pos) =
71 :			CML.send(drawCh, DrawBall(n, ballIcon, subPt(pos, offset)))
72 :			fun moveBall (n, oldPos, newPos) = (
73 :			drawBall(n, oldPos); drawBall(n, newPos))
74 :			val clipFn = clip (ballRadius, sz)
75 :			fun ball (inEvt, pos, vec, clipFn) = let
76 :			fun loop (seqn, pos, vec, clipFn) = CML.select [
77 :			CML.wrap(delayEvt, fn () => let
78 :			val (newPos, newVec) = clipFn(pos, vec)
79 :			in
80 :			if (pos <> newPos)
81 :			then moveBall(seqn, pos, newPos)
82 :			else ();
83 :			loop(seqn, newPos, newVec, clipFn)
84 :			end),
85 :			CML.wrap(inEvt,
86 :			fn (KILL(PT{x, y})) => let
87 :			val deathZone = RECT{
88 :			x = x-ballRadius, y = y-ballRadius,
89 :			wid = 2*ballRadius, ht = 2*ballRadius}
90 :			in
91 :			if within(pos, deathZone)
92 :			then drawBall(seqn, pos)
93 :			else loop(seqn, pos, vec, clipFn)
94 :			end
95 :			| (REDRAW(seqn', newSz)) => let
96 :			val clipFn = clip (ballRadius, newSz)
97 :			val (newPos, _) = clipFn(pos, PT{x=0, y=0})
98 :			in
99 :			drawBall(seqn', pos);
100 :			loop (seqn', newPos, vec, clipFn)
101 :			end
102 :			| KILL_ALL => drawBall(seqn, pos))
103 :			]
104 :			in
105 :			drawBall (seqn, pos);
106 :			loop (seqn, pos, vec, clipFn)
107 :			end
108 :			in
109 :			XDebug.xspawn (
110 :			"Ball",
111 :			fn () =>
112 :			ball(MChan.recvEvt(MChan.port mchan), pos, vec, clipFn));
113 :			()
114 :			end
115 :			in
116 :			newBall
117 :			end
118 :
119 :			end (* local *)
120 :			end (* Ball *)

---

root@smlnj-gforge.cs.uchicago.edu	ViewVC Help
Powered by ViewVC 1.0.0