How to set random colour once ?

General
1

Hi there,

I have been playing with the particle example to try and learn a bit more.

more.

    p={}
ps=500

-- Use this function to perform your initial setup
function setup()
   print("Hello World!")
   for i=0,ps do
   
       p[i]= {x=math.random(WIDTH*10)/10,
y=math.random(HEIGHT*10)/10, ox=0.0, oy=0.0, vx=math.random(20)-10,
vy=math.random(20)-10}
 
   end
end

-- This function gets called once every frame
function draw()
   noSmooth()

   background(10,10,20)
   fill(255,0,0)
   

   for i=0,ps do
    
   stroke(math.random(0,255), math.random(0,255), math.random(0,255), 255)
   strokeWidth(3)

       p[i].ox= p[i].x
       p[i].oy= p[i].y
       p[i].x = p[i].x + p[i].vx
       p[i].y = p[i].y + p[i].vy


       if p[i].x<0 then
           p[i].x=0
           p[i].vx= -p[i].vx
       end

       if p[i].y<0 then
           p[i].y=0
           p[i].vy= -p[i].vy
       end

       if p[i].x>WIDTH then
           p[i].x=WIDTH
           p[i].vx= -p[i].vx
       end

       if p[i].y>HEIGHT then
           p[i].y=HEIGHT
           p[i].vy= -p[i].vy
       end

       p[i].vx = p[i].vx*0.98
       p[i].vy = p[i].vy*0.98

       line(p[i].ox, p[i].oy, p[i].x, p[i].y)
   end
end

function touched(t)
   a=10
   for i=0,ps do
       d= (p[i].x-t.x)*(p[i].x-t.x) + (p[i].y-t.y)*(p[i].y-t.y)
       d= math.sqrt(d)
       p[i].vx = p[i].vx - a/d*(p[i].x-t.x)
       p[i].vy = p[i].vy - a/d*(p[i].y-t.y)

   end
end

The problem is that it changes the colour of each dot each time instead of setting the colour randomly once (if that makes sense)

How would I go about just settings a random colour for each dot just once so it doesn’t change ?

Thanks
Lee

2

Can you put 3 tildas ~ like this: — at the beginning and end of your code?

3

Thank you, I was trying to work that one out lol

4

Do that: (nice effects, btw): i transfered the color creation in the setup, in a table, like you ‘p’


--# Main
    p={}
ps=500

-- Use this function to perform your initial setup
function setup()
   print("Hello World!")
    c={}
   for i=0,ps do

       p[i]= {x=math.random(WIDTH*10)/10,
y=math.random(HEIGHT*10)/10, ox=0.0, oy=0.0, vx=math.random(20)-10,
vy=math.random(20)-10}
        c[i]=color(math.random(0,255), math.random(0,255), math.random(0,255), 255)
   end
end

-- This function gets called once every frame
function draw()
   noSmooth()

   background(10,10,20)
   fill(255,0,0)


   for i=0,ps do

   stroke(c[i])
   strokeWidth(3)

       p[i].ox= p[i].x
       p[i].oy= p[i].y
       p[i].x = p[i].x + p[i].vx
       p[i].y = p[i].y + p[i].vy


       if p[i].x<0 then
           p[i].x=0
           p[i].vx= -p[i].vx
       end

       if p[i].y<0 then
           p[i].y=0
           p[i].vy= -p[i].vy
       end

       if p[i].x>WIDTH then
           p[i].x=WIDTH
           p[i].vx= -p[i].vx
       end

       if p[i].y>HEIGHT then
           p[i].y=HEIGHT
           p[i].vy= -p[i].vy
       end

       p[i].vx = p[i].vx*0.98
       p[i].vy = p[i].vy*0.98

       line(p[i].ox, p[i].oy, p[i].x, p[i].y)
   end
end

function touched(t)
   a=10
   for i=0,ps do
       d= (p[i].x-t.x)*(p[i].x-t.x) + (p[i].y-t.y)*(p[i].y-t.y)
       d= math.sqrt(d)
       p[i].vx = p[i].vx - a/d*(p[i].x-t.x)
       p[i].vy = p[i].vy - a/d*(p[i].y-t.y)

   end
end
5

If you in the beginning of the draw function set a random seed value, then I think it will work for you.