summaryrefslogtreecommitdiffstats
path: root/examples/script/context2d/scripts/pong.js
blob: 2bff053f334685700921bde42fca9f0292a8d201 (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
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
// globals
playarea_canvas = document.getElementById('tutorial');
playarea_canvas.resize(320,200);
playarea = playarea_canvas.getContext('2d');
//p1_scr = document.getElementById('p1_scr');
//p2_scr = document.getElementById('p2_scr');
//status_msg = document.getElementById('status');
//debug = document.getElementById('debug');
ball_direction = 0;
up = -1;
down = 1;

//key codes
key_up = 38;
key_down = 40;
key_W = 87;
key_S = 83;
key_pause = 32;

speed = 2;			//controls the speed of the ball
paddle_inc = 10;	//how many pixels paddle can move in either direction
pause = false;

player_1 = 0;		//player IDs
player_2 = 1;
player_1_scr = 0;	//player scores
player_2_scr = 0;
player_1_direction = null;	//null = no movement whatsoever
player_2_direction = null;

pa = new Array();
divider = new Array();
paddle_1 = new Array();
paddle_2 = new Array();
ball = new Array();


function sleep(numberMillis)
{
    var now = new Date();
    var exitTime = now.getTime() + numberMillis;
    while (true) {
	now = new Date();
	if (now.getTime() > exitTime)
	    return;
    }
}

function init()
{
    pa['width'] = 150;
    pa['height'] = 140;
    pa['player_margin'] = 10;		//area behind player paddles
    pa['foreground'] = "#FFFFFF";
    pa['background'] = "#000000";

    divider['pos'] = pa['width']/2;
    divider['width'] = 4;

    paddle_1['width'] = 8;
    paddle_1['height'] = 64;
    paddle_1['x'] = pa['player_margin'];
    paddle_1['y'] = (pa['height'] /2 ) - (paddle_1['height'] / 2);

    paddle_2['width'] = 8;
    paddle_2['height'] = 64;
    paddle_2['x'] = (pa['width'] - pa['player_margin'] - paddle_2['width']);
    paddle_2['y'] = (pa['height'] /2 ) - (paddle_2['height'] / 2);

    ball['width'] = 10;
    ball['height'] = 10;
    ball['x'] = (pa['width']/2) - (ball['width'] / 2);
    ball['y'] = (pa['height']/2) - (ball['height'] / 2);

    ball_direction = Math.random() * 360;	//initialize ball direction, which is determined by angle, at random
    speed = 2;
}

function renderPlayarea()
{
    playarea.beginPath();

    playarea.clearRect(0,0,pa['width'],pa['height']);
    playarea.fillStyle = pa['background'];
    playarea.strokeStyle = pa['foreground'];
    playarea.fillRect(0,0, pa['width'], pa['height']);

    //move paddles
    if(player_1_direction != null)
	{
	    if(player_1_direction == up)
		paddle_1['y'] = paddle_1['y'] - paddle_inc;
	    else
		paddle_1['y'] = paddle_1['y'] + paddle_inc;
	}
    if(player_2_direction != null)
	{
	    if(player_2_direction == up)
		paddle_2['y'] = paddle_2['y'] - paddle_inc;
	    else
		paddle_2['y'] = paddle_2['y'] + paddle_inc;
	}
    playarea.rect(paddle_1['x'],paddle_1['y'],paddle_1['width'],paddle_1['height']);
    playarea.rect(paddle_2['x'],paddle_2['y'],paddle_2['width'],paddle_2['height']);

    //move ball
    playarea.rect(ball['x'], ball['y'], ball['width'], ball['height']);
    ball['x'] = ball['x'] + Math.cos((ball_direction)*Math.PI/180) * speed;
    ball['y'] = ball['y'] + Math.sin((ball_direction)*Math.PI/180) * speed;

    playarea.fillStyle = pa['foreground'];
    playarea.fill();

    playarea.beginPath();
    //redraw divider
    playarea.lineWidth = divider['width'];
    playarea.lineTo(divider['pos'], 0);
    playarea.lineTo(divider['pos'], pa['height'] = 200);
    playarea.lineWidth = 1;

    playarea.stroke();
    playarea.closePath();
}

function testCollisions()
{
    //make sure paddles don't go beyond play area
    if(((paddle_1['y'] <= 0) &&	(player_1_direction == up)) || ((paddle_1['y'] >= (pa['height'] - paddle_1['height'])) && (player_1_direction == down)))
	player_1_direction = null;
    if(((paddle_2['y'] <= 0) &&	(player_2_direction == up)) || ((paddle_2['y'] >= (pa['height'] - paddle_2['height'])) && (player_2_direction == down)))
	player_2_direction = null;

    //check to see if ball went beyond paddles, and if so, score accordingly and reset playarea
    if(ball['x'] <= 0)
	{
	    setScore(player_2);
	    init()
		sleep(1000);
	}
    if(ball['x'] >= (pa['width'] - ball['width']))
	{
	    setScore(player_1);
	    init();
	    sleep(1000);
	}

    //check to see if ball hit top or bottom wall. if so, change direction
    if((ball['y'] >= (pa['height'] - ball['height'])) || ball['y'] <= 0)
	ball_direction = -ball_direction;

    //check to see if the ball hit a paddle, and if so, change ball angle dependant on where it hit the paddle
    if((ball['x'] <= (paddle_1['x'] + paddle_1['width'])) && (ball['y'] >= paddle_1['y']) && (ball['y'] <= (paddle_1['y'] + paddle_1['height'])))
	{
	    ball_direction = -ball_direction/2;
	    speed += .5;
	}
    if(((ball['x'] + ball['width']) >= paddle_2['x']) && (ball['y'] >= paddle_2['y']) && (ball['y'] <= (paddle_2['y'] + paddle_2['height'])))
	{
	    ball_direction = (180+ball_direction)/2;
	    speed += .5;
	}
}

function setScore(p)
{
    if(p == player_1)
	{
	    player_1_scr++;
	    //p1_scr.firstChild.nodeValue = player_1_scr;
	}
    if(p == player_2)
	{
	    player_2_scr++;
	    //p2_scr.firstChild.nodeValue = player_2_scr;
	}
}


//handle input
document.onkeydown = function(ev)
{
    switch(ev.keyCode)
    {
	case key_W:
	player_1_direction = up;
	break;
	case key_S:
	player_1_direction = down;
	break;
	case key_up:
	player_2_direction = up;
	break;
	case key_down:
	player_2_direction = down;
	break;
    }
}

document.onkeyup = function(ev)
{
    switch(ev.keyCode)
    {
	case key_W:
	case key_S:
	player_1_direction = null;
	break;
	case key_up:
	case key_down:
	player_2_direction = null;
	break;
	case key_pause:
	if(pause == false)
	{
	    clearInterval(game);
	    //status_msg.style.visibility = "visible";
	    pause = true;
	}
	else
	{
	    game = setInterval(main, 25);
	    //status_msg.style.visibility = "hidden";
	    pause = false;
	}
	break;
    }
}

function main()
{
    testCollisions();
    renderPlayarea();
}

init();
game = setInterval(main, 25);