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hypotrochoid (Read 460 times)
yeolesquid
hypotrochoid
Aug 5th, 2006, 7:29am  
Hello everyone!  I am new to Processing and coding in general. I am trying to learn how to take a concept and continue towards a complete code.  Currently, I am trying to reproduce a spirograph-type image using a hypotochoid equation [http://mathworld.wolfram.com/Hypotrochoid.html]

I'm getting better but I have a lot to learn.  I can't take the figure out the next step.  Because I'm close to clueless, I am graciously asking for help.
This is what I have so far:

int r = 5;
int R = 30;
int d = 70;
float theta;
float rot;
int dif = R - r;

void setup () {
 size (500,500);
 background (0);
 stroke (255);
}

void draw () {
 
 theta = radians(rot);
 rot=rot+1;
 translate (width/2,height/2);
 point (dif * cos(theta) + d * cos((dif/r)*theta), dif * sin(theta) + d * sin((dif/r)*theta));
}

These are the questions I have about my code:
1) How do I create a single clean line quickly rather than a dotted line?

2) is there a way to create a spirograph shape without using the draw() function? In other words, I would like to know how to be able to animate this function as well as just creating a still picture.

Thanks in advance! I'm looking forward to seeing a solution.
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funkopatomus  
Bas
Re: hypotrochoid
Reply #1 - Aug 5th, 2006, 2:30pm  
Hi there! I've been using processing for a few days now. I'm not really that mathematically skilled to understand the spirograph-type math you're using, but it looks neat though.

You could try to use the line() function and calculate the starting & ending locations (points) for every line.

Quote:

int r = 5;
int R = 30;
int d = 70;
float theta = 0;
float rot;
int dif = R - r;
float x1, y1, x2, y2;

void setup () {  
 size (500,500);
 background (0);
 stroke (255);
}

void draw () {
 x1 = dif * cos(theta) + d * cos((dif/r)*theta);
 y1 = dif * sin(theta) + d * sin((dif/r)*theta);
 rot++;
 theta = radians(rot);
 x2 = dif * cos(theta) + d * cos((dif/r)*theta);
 y2 = dif * sin(theta) + d * sin((dif/r)*theta);  
 translate(width/2,height/2);  
 line(x1,y1,x2,y2);
}
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« Last Edit: Aug 5th, 2006, 4:52pm by Bas »  
 
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