Re: random points near central point

From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.lang.c
Subject	Re: random points near central point
Date	2023-07-20 20:59 +0100
Organization	A noiseless patient Spider
Message-ID	<87sf9ipd5e.fsf@bsb.me.uk> (permalink)
References	<eb9e82fb-265b-42a7-a245-1943e5b3b5aan@googlegroups.com> <87tttzr9h0.fsf@bsb.me.uk> <a0756188-052d-406b-8fe8-7c6a071be044n@googlegroups.com> <874jlyqsi1.fsf@bsb.me.uk> <2c181aeb-49e4-45b8-8be1-fc1189878e3en@googlegroups.com>

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fir <profesor.fir@gmail.com> writes:

> czwartek, 20 lipca 2023 o 21:43:02 UTC+2 Ben Bacarisse napisał(a):
>> fir <profes...@gmail.com> writes: 
>> 
>> > środa, 19 lipca 2023 o 21:24:09 UTC+2 Ben Bacarisse napisał(a): 
>> >> fir <profes...@gmail.com> writes: 
>> >> 
>> >> > i need tos et asteroids in game (about 100 or 200) but not in square 
>> >> > area with two rands one for x and second for y but need it to 
>> >> > be sphericel symetric around central point and in more densitu near it 
>> >> > and less desity with bigger radius until some radius when it is zero 
>> >> If you just pick a uniform angle and a uniform radius and plot those 
>> >> points, the density of points near the origin will be higher. This is a 
>> >> very simple method and might be suitable for a game. 
>> > 
>> > uniform radius? dont know what is that
>> Uniform refers to a statistical distribution with uniform density -- 
>> every result in some range is equally likely. Your random number 
>> generator will have a function to give you a number uniformly 
>> distributed in some range (often >= 0.0 to < 1.0). I'll use drand48() 
>> as an example. 
>> 
>> double pi = 4 * atan(1); 
>> double r = drand48(); 
>> double a = 2 * pi * drand48(); 
>> 
>> Now if you plot the point at angle a and distance r from (0,0) you will 
>> see that they all lie in the unit circle but they cluster round the 
>> origin. 
>> 
>> Obviously you can convert polar coordinates r and a to Cartesian x and y 
>> with 
>> 
>> double x = r * cos(a), y = r * sin(a); 
>> 
>> I'm not sure if this is what you want, but it sounds like it from some 
>> of the words you used. 
>
> no i just need to add rangom grou[p which is randomly spgerical amd
> has more density near centre and which get downs to zero at some
> radius R2 the centre of it (with some radius R) should have some flat
> density ...iys not just much important what but flad

I wish you well.  If you want to ask in a group where English is widely
used, can you find someone to review your posts?  I have no idea what
you are asking, but please don't spend any time explaining it -- I don't
need to know.

-- 
Ben.

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random points near central point fir <profesor.fir@gmail.com> - 2023-07-18 23:38 -0700
  Re: random points near central point Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-07-19 01:49 -0700
    Re: random points near central point fir <profesor.fir@gmail.com> - 2023-07-19 04:20 -0700
  Re: random points near central point Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-07-19 01:59 -0700
  Re: random points near central point Kaz Kylheku <864-117-4973@kylheku.com> - 2023-07-19 16:50 +0000
  Re: random points near central point Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-07-19 20:23 +0100
    Re: random points near central point fir <profesor.fir@gmail.com> - 2023-07-20 09:31 -0700
      Re: random points near central point Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-07-20 20:42 +0100
        Re: random points near central point fir <profesor.fir@gmail.com> - 2023-07-20 12:56 -0700
          Re: random points near central point Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-07-20 20:59 +0100
          Re: random points near central point David Brown <david.brown@hesbynett.no> - 2023-07-21 09:13 +0200
            Re: random points near central point fir <profesor.fir@gmail.com> - 2023-07-21 05:55 -0700
              Re: random points near central point Ed Prochak <edprochak@gmail.com> - 2023-07-22 12:24 -0700
                Re: random points near central point fir <profesor.fir@gmail.com> - 2023-07-23 04:04 -0700
                Re: random points near central point Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-07-23 14:53 +0100
                Re: random points near central point fir <profesor.fir@gmail.com> - 2023-07-23 07:03 -0700
                Re: random points near central point "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-07-23 12:30 -0700
                Re: random points near central point Ed Prochak <edprochak@gmail.com> - 2023-07-30 21:48 -0700
        Re: random points near central point fir <profesor.fir@gmail.com> - 2023-07-20 13:20 -0700
      Re: random points near central point "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-07-20 12:57 -0700
        Re: random points near central point fir <profesor.fir@gmail.com> - 2023-07-20 13:18 -0700
          Re: random points near central point "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-07-23 12:28 -0700
  Re: random points near central point "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-07-20 12:56 -0700

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