Processing 1.0 - Processing Discourse - Points distributed round a circle

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Points distributed round a circle (Read 575 times)

tomski YaBB Newbies Offline Posts: 4	Points distributed round a circle Apr 9^th, 2008, 8:37pm Hi, I'm suffering from a very poor mathematics background here.... Ideally I'd like to be able to specify n points then for those points to be drawn, evenly distributed round a circle - I can happily cope with straight lines its circles that confuse me - can anybody point me to an example? Thanks Tomski

JohnG

Re: Points distributed round a circle
Reply #1 - Apr 9^th, 2008, 8:51pm

It's really simple really. you just take 360' and divide it by the number of points, and draw one every X degrees.

In processing it's TWO_PI radians in a circle, but the principal is the same.

Code:

float radius=50;
int numPoints=20;
float angle=TWO_PI/(float)numPoints;
for(int i=0;i<numPoints;i++)
{
  point(radius*sin(angle*i),radius*cos(angle*i));
}

tomski YaBB Newbies Offline Posts: 4	Re: Points distributed round a circle Reply #2 - Apr 9^th, 2008, 9:02pm Great thanks for the speedy reply - I knew it would be simple, it just takes a little while to become familiar with the building blocks for this type of code;)

tomski

Re: Points distributed round a circle
Reply #3 - Apr 10^th, 2008, 7:34pm

I further developed the "distributed circle" code. which works great, however, the lines drawn (I created a series of points that all link to each other) don't seem to be anti-aliased - what can I do to smooth them? i.e. smooth(); doesn't do as I expect...

Code:


// Global variables
float radius = 150; // Size of the circle
int numPoints = 11; // Number of points on the circe
float angle=TWO_PI/(float)numPoints; // Calculate the angle each point is on
float[][] xyArray; // Declare an array

void setup(){
  smooth();
  strokeWeight(1);
  height = 500; // Window height
  width = 500;  // Window width
  background(51);
  // CREATE A LIST OF x & y CO-ORDINATES
  xyArray = new float [numPoints][3]; // Setup the array dimentions
  for(int i=0;i<numPoints;i++) { 
    float x = radius*sin(angle*i)+width/2;
    float y = radius*cos(angle*i)+height/2;
    xyArray[i][0] = x; // Store the x co-ordinate
    xyArray[i][1] = y; // Store the x co-ordinate
    xyArray[i][2] = 0.0;
  }
}

void draw(){     
  // Draw the shape
  for(int i=0;i<numPoints;i++){ 
    float x = xyArray[i][0];
    float y = xyArray[i][1];
    for(int ii=i+1;ii<numPoints;ii++){ 
      if(ii>i){
        float xx = xyArray[ii][0];
        float yy = xyArray[ii][1];  
        strokeWeight(1);
        line(x, y, xx, yy);
      }
    }
    strokeWeight(1);
    ellipse(x, y, 5, 5);
  }
}

tomski YaBB Newbies Offline Posts: 4	Re: Points distributed round a circle Reply #4 - Apr 10^th, 2008, 7:44pm ignore me - playing around with background colors solves the issue..... boy have I got allot to learn about processing....

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