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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
|
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>Apache Tomcat WebSocket Examples: Multiplayer Snake</title>
<style type="text/css"><![CDATA[
#playground {
width: 640px;
height: 480px;
background-color: #000;
}
#console-container {
float: left;
margin-left: 15px;
width: 300px;
}
#console {
border: 1px solid #CCCCCC;
border-right-color: #999999;
border-bottom-color: #999999;
height: 480px;
overflow-y: scroll;
padding-left: 5px;
padding-right: 5px;
width: 100%;
}
#console p {
padding: 0;
margin: 0;
}
]]></style>
</head>
<body>
<div class="noscript"><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websockets rely on Javascript being enabled. Please enable
Javascript and reload this page!</h2></div>
<div style="float: left">
<canvas id="playground" width="640" height="480"/>
</div>
<div id="console-container">
<div id="console"/>
</div>
<script type="application/javascript"><![CDATA[
var Game = {};
Game.fps = 30;
Game.socket = null;
Game.nextFrame = null;
Game.interval = null;
Game.direction = 'none';
Game.gridSize = 10;
function Snake() {
this.snakeBody = [];
this.color = null;
}
Snake.prototype.draw = function(context) {
for (var id in this.snakeBody) {
context.fillStyle = this.color;
context.fillRect(this.snakeBody[id].x, this.snakeBody[id].y, Game.gridSize, Game.gridSize);
}
};
Game.initialize = function() {
this.entities = [];
canvas = document.getElementById('playground');
if (!canvas.getContext) {
Console.log('Error: 2d canvas not supported by this browser.');
return;
}
this.context = canvas.getContext('2d');
window.addEventListener('keydown', function (e) {
var code = e.keyCode;
if (code > 36 && code < 41) {
switch (code) {
case 37:
if (Game.direction != 'east') Game.setDirection('west');
break;
case 38:
if (Game.direction != 'south') Game.setDirection('north');
break;
case 39:
if (Game.direction != 'west') Game.setDirection('east');
break;
case 40:
if (Game.direction != 'north') Game.setDirection('south');
break;
}
}
}, false);
if (window.location.protocol == 'http:') {
Game.connect('ws://' + window.location.host + '/examples/websocket/snake');
} else {
Game.connect('wss://' + window.location.host + '/examples/websocket/snake');
}
};
Game.setDirection = function(direction) {
Game.direction = direction;
Game.socket.send(direction);
Console.log('Sent: Direction ' + direction);
};
Game.startGameLoop = function() {
if (window.webkitRequestAnimationFrame) {
Game.nextFrame = function () {
webkitRequestAnimationFrame(Game.run);
};
} else if (window.mozRequestAnimationFrame) {
Game.nextFrame = function () {
mozRequestAnimationFrame(Game.run);
};
} else {
Game.interval = setInterval(Game.run, 1000 / Game.fps);
}
if (Game.nextFrame != null) {
Game.nextFrame();
}
};
Game.stopGameLoop = function () {
Game.nextFrame = null;
if (Game.interval != null) {
clearInterval(Game.interval);
}
};
Game.draw = function() {
this.context.clearRect(0, 0, 640, 480);
for (var id in this.entities) {
this.entities[id].draw(this.context);
}
};
Game.addSnake = function(id, color) {
Game.entities[id] = new Snake();
Game.entities[id].color = color;
};
Game.updateSnake = function(id, snakeBody) {
if (typeof Game.entities[id] != "undefined") {
Game.entities[id].snakeBody = snakeBody;
}
};
Game.removeSnake = function(id) {
Game.entities[id] = null;
// Force GC.
delete Game.entities[id];
};
Game.run = (function() {
var skipTicks = 1000 / Game.fps, nextGameTick = (new Date).getTime();
return function() {
while ((new Date).getTime() > nextGameTick) {
nextGameTick += skipTicks;
}
Game.draw();
if (Game.nextFrame != null) {
Game.nextFrame();
}
};
})();
Game.connect = (function(host) {
if ('WebSocket' in window) {
Game.socket = new WebSocket(host);
} else if ('MozWebSocket' in window) {
Game.socket = new MozWebSocket(host);
} else {
Console.log('Error: WebSocket is not supported by this browser.');
return;
}
Game.socket.onopen = function () {
// Socket open.. start the game loop.
Console.log('Info: WebSocket connection opened.');
Console.log('Info: Press an arrow key to begin.');
Game.startGameLoop();
setInterval(function() {
// Prevent server read timeout.
Game.socket.send('ping');
}, 5000);
};
Game.socket.onclose = function () {
Console.log('Info: WebSocket closed.');
Game.stopGameLoop();
};
Game.socket.onmessage = function (message) {
// _Potential_ security hole, consider using json lib to parse data in production.
var packet = eval('(' + message.data + ')');
switch (packet.type) {
case 'update':
for (var i = 0; i < packet.data.length; i++) {
Game.updateSnake(packet.data[i].id, packet.data[i].body);
}
break;
case 'join':
for (var j = 0; j < packet.data.length; j++) {
Game.addSnake(packet.data[j].id, packet.data[j].color);
}
break;
case 'leave':
Game.removeSnake(packet.id);
break;
case 'dead':
Console.log('Info: Your snake is dead, bad luck!');
Game.direction = 'none';
break;
case 'kill':
Console.log('Info: Head shot!');
break;
}
};
});
var Console = {};
Console.log = (function(message) {
var console = document.getElementById('console');
var p = document.createElement('p');
p.style.wordWrap = 'break-word';
p.innerHTML = message;
console.appendChild(p);
while (console.childNodes.length > 25) {
console.removeChild(console.firstChild);
}
console.scrollTop = console.scrollHeight;
});
Game.initialize();
document.addEventListener("DOMContentLoaded", function() {
// Remove elements with "noscript" class - <noscript> is not allowed in XHTML
var noscripts = document.getElementsByClassName("noscript");
for (var i = 0; i < noscripts.length; i++) {
noscripts[i].parentNode.removeChild(noscripts[i]);
}
}, false);
]]></script>
</body>
</html>
|
