 |
Author |
Topic: Some Trig Help (Read 2162 times) |
|
dlarrivee
|
Some Trig Help
« on: Apr 17th, 2005, 5:01pm » |
|
I have a circle that I would like to draw a line from the center of, and make it go out to the edge of the circle, I'd like to be able to draw this line on all 360 degrees, but I'm not sure what to do, maybe someone who is good with trig and can viualize these things can help, here's what I have so far:
Code:
int x, y, diam, rad;
int edgex, edgey;
int centerx, centery;
void setup() {
size(500, 500);
diam = 400;
rad = diam/2;
centerx = width/2;
centery = width/2;
x = centerx - rad;
y = centery - rad;
background(255);
}
void loop() {
edgex = centerx;
edgey = centery - rad;
stroke(0);
ellipse(x, y, diam, diam);
stroke(255, 0, 0);
line(centerx, centery, edgex, edgey);
stroke(0);
//ellipse(x + 150/2, y + 150/2, diam - 150, diam - 150);
}
|
|
|
|
|
|
|
alankilian
|
Re: Some Trig Help
« Reply #1 on: Apr 17th, 2005, 7:02pm » |
|
I don't know anything about Java's trig routines, but here is something to get you started.
Make a variable "angle" that will count from 0 to 359
edjex = centerx + (cos(angle)*rad)
edgey = centery + (sin(angle)*rad)
draw from (centerx,contery) to (edgex,edgey)
increment the variable angle by 45, 5, or 1 degrees.
loop.
Now, you will need to figure out of Java's sin and cos routines take a value of degrees or radians.
If they take radians, divide your angle by (2*PI) so
that you have sin(angle/(2*PI)) etc.
Let us know how it works out for you.
|
| « Last Edit: Apr 17th, 2005, 7:03pm by alankilian » |
|
|
|
|
fry
|
Re: Some Trig Help
« Reply #2 on: Apr 17th, 2005, 9:47pm » |
|
actually if you want to convert from degrees, just use:
edjex = centerx + (cos(radians(angle))*rad)
edgey = centery + (sin(radians(angle))*rad)
(sin and cos take radians)
|
|
|
|
|
mflux
|
Re: Some Trig Help
« Reply #3 on: Apr 17th, 2005, 10:30pm » |
|
Code:
edjex = centerx + (cos(radians(angle))*rad)
edgey = centery + (sin(radians(angle))*rad)
|
|
Hey Ben.
Correction: Isn't edgey supposed to be
edgey = centery - (sin(radians(angle))*rad)
since screen units of y counts downwards?
|
|
|
|
|
fry
|
Re: Some Trig Help
« Reply #4 on: Apr 18th, 2005, 1:55am » |
|
oh, could be.. i was only commenting on the radians() stuff.. didn't look at the code closely.
|
|
|
|
|
dlarrivee
|
Re: Some Trig Help
« Reply #5 on: Apr 18th, 2005, 3:47am » |
|
Wow, thanks alot. That works quite well!
|
|
|
|
|
|
