drawing angle as line around point

beginners
#1

hi folks,
i’m really bad at math can you please help me:

i want to draw a line starting at a given point with a fixed length and an given angle. The Endpoint of the line should cirle around the starting point, like a compass needle. I want to use vectors. how can i translate the angle (in degrees or radiant) to the endpoint.

I think there are several methods, i also would like to see an example with rotation.

Help would be awesome.
cheers

#2

I always think the easiest thing is to have some variable that you increment to 2 * PI, which is the number of radians in a circle, and use the cos of that variable to find the X position to draw and the sin of that variable to find the Y position to draw:

  
  
  float pos = 0.0;  
  while( pos < TWO_PI) {  
    ofVertex( cos(pos)*100, sin(pos)*100);  
    pos+=0.01;  
  }

You can use this inside ofBeginShape() and ofEndShape() or you can use it with an ofShape to add points.