Q: function for positive to negative

Fri, 09 Jun 2017 01:49:35 UTC

I'm trying to write a function to switch negative to positive and vise-versa. I've got:

foot=3

function switch(f)
 f*=-1
end

when I call switch(foot) it returns the original value but if at the command prompt I type "foot*=-1 it preforms as expected.

Thanks for any help and sorry for these remedial questions.

--
-john

Q: orbiting around a point

Thu, 08 Jun 2017 03:13:05 UTC

I would like to create a function that would move one point in along a circle around another, but lack the math know how.

here's what I have cobbled together from examples elsewhere and a little help, hopefully at least my intentions are clear (the inc=increment would let me fiddle with how fast p2 travels)

point1={}
point1.x=68
point1.y=78

point2={}
point2.x=57
point2.y=43

function orbit(p1, p2, inc)
distance = sqrt((p1.x-p2.x)(p1.x-p2.x) + (p1.y-p2.y)(p1.y-p2.y))
ang= atan2(p2.y, p2.x) - atan2(p1.y, p2.x)
p2.x=(p1.x + distance cos(ang+inc))
p2.y=(p1.y + distance sin(ang+inc))
end

function _update()
orbit(point1, point2, .01)
end

function _draw()
line(point1.x, point1.y, point2.x, point2.y, 7)
end

--
-john

xyzzy [Lexaloffle Blog Feed]

Q: function for positive to negative

Q: orbiting around a point