-
Notifications
You must be signed in to change notification settings - Fork 4
/
random_squiggle.js
195 lines (149 loc) · 5.63 KB
/
random_squiggle.js
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
/**
*
* This class is licensed under Creative Commons Attribution 3.0 License:
* http://creativecommons.org/licenses/by/3.0/
* Essentially you are free to use this class in any way you want, but anywhere
* you list credits for a work which uses this class you need to also acknowledge
* this classes author.
*
* @author Noel Billig (http://www.dncompute.com)
* @author Alexander Veenendaal (http://opendoorgonorth.com/)
*
* Based on http://www.dncompute.com/blog/2007/03/19/seed-based-pseudorandom-number-generator-in-actionscript.html
*/
(function (definition) {
// RequireJS/CommonJS/<script> adapter taken from https://raw.github.com/kriskowal/q/master/q.js by Kris Kowal
// This file will function properly as a <script> tag, or a module
// using CommonJS and NodeJS or RequireJS module formats. In
// Common/Node/RequireJS, the module exports the RandomSquiggle API and when
// executed as a simple <script>, it creates a RandomSquiggle global instead.
// RequireJS
if (typeof define === "function") {
define(definition);
// CommonJS
} else if (typeof exports === "object") {
definition(void 0, exports);
// <script>
} else {
definition(void 0, RandomSquiggle = {});
}
})(function (require, exports) {
var RandomSquiggle = function(){
};
RandomSquiggle.prototype.generate = function(seed){
if( typeof seed !== "undefined" ){
random.seed = seed;
}
this.context.fillStyle = '#FFFFFF';
this.context.fillRect( 0,0, this.width, this.height );
this.margin = 50;
//The turtle represents the tip of our drawing pen
this.turtle = {
x:this.width/2, //X,Y is the turtle position
y:this.height/2,
theta:0, //Theta,radius is the turtle velocity in polar coordiantes
radius:1,
colour:ColourValue.create( random.nextInt() ),//randomColour(),
alpha:50,
thickness:1
};
this.context.lineWidth = 1;
this.context.strokeStyle = this.turtle.colour.toString();
this.colourRateChange = random.nextDoubleRange(0,10);
//Theta range is essentially how fast the turtle turns
this.thetaRange = this.random.nextIntRange(0,180);
this.randomizeThetaRange = this.random.nextBoolean();
}
/**
* @param degrees Number in degrees
* @return Number in radians
*/
var degreesToRadians = function(degrees) {
return (degrees / 180) * Math.PI;
}
/**
* @param radians Number in radians
* @return Number in degrees
*/
var radiansToDegrees = function(radians) {
return (radians * 180) / Math.PI;
}
/**
* @param x Number
* @param y Number
* @return Object A vector with two properties, r and theta.
*/
var cartesianToPolar = function(x,y) {
var result = {};
result.r = Math.sqrt( Math.pow(x,2)+Math.pow(y,2) );
var theta = Math.atan2(y,x);
result.theta = radiansToDegrees( theta );
result.toString = function() { return "[Vector r="+result.r+" theta="+result.theta+"]"; };
return result;
};
/**
* @param r Number Length of the vector
* @param theta Number The angle of the vector
* @return Object A vector with two properties, x and y.
*/
var polarToCartesian = function(r,theta) {
var thetaInRadians = degreesToRadians(theta);
var result = {};
result.x = r*Math.cos( thetaInRadians );
result.y = r*Math.sin( thetaInRadians );
result.toString = function() { return "[Vector x="+result.x+" y="+result.y+"]"; };
return result;
};
RandomSquiggle.prototype.draw = function(){
var self = this,
turtle = this.turtle,
random = this.random,
thetaRange = this.thetaRange,
velocity,
rgb, colourRateChange = this.colourRateChange;
this.context.beginPath();
this.context.moveTo(this.turtle.x,this.turtle.y);
//Adjust Alpha
turtle.alpha += random.nextDoubleRange(-10,7);
turtle.alpha = Math.max( 5, Math.min( 100, turtle.alpha ) );
//Adjust Thickness
turtle.thickness += random.nextDoubleRange(-1,1);
turtle.thickness = Math.max( 1, Math.min( turtle.thickness, 5 ));
//Adjust Color
rgb = turtle.colour.clone();
rgb.r += random.nextDoubleRange(-this.colourRateChange,this.colourRateChange);
rgb.g += random.nextDoubleRange(-this.colourRateChange,this.colourRateChange);
rgb.b += random.nextDoubleRange(-this.colourRateChange,this.colourRateChange);
turtle.colour.setRGB(rgb.r,rgb.g,rgb.b,turtle.alpha);
//Change LineStyle
this.context.lineWidth = turtle.thickness;
this.context.strokeStyle = turtle.colour.toString();
//Reposition Turtle
if (this.randomizeThetaRange) thetaRange = random.nextDoubleRange(0,180);
turtle.radius = random.nextIntRange(1,10);
turtle.theta += random.nextIntRange(-thetaRange,thetaRange);
velocity = polarToCartesian(turtle.radius,turtle.theta);
turtle.x += velocity.x;
turtle.y += velocity.y;
this.context.lineTo( this.turtle.x, this.turtle.y );
this.context.stroke();
//If we're out of bounds, redirect the turtle back towards the center
if (
(this.turtle.x > (this.width-this.margin)) ||
(this.turtle.x < this.margin) ||
(this.turtle.y > (this.height-this.margin)) ||
(this.turtle.y < this.margin)
) {
directToCenter = cartesianToPolar(-turtle.x+(this.width/2),-turtle.y+(this.height/2));
turtle.theta = directToCenter.theta;
}
}
exports.create = function( canvas, random ){
var result = new RandomSquiggle();
result.context = canvas.getContext('2d');
result.random = random;
result.width = canvas.width;
result.height = canvas.height;
return result;
};
});