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Topic: boring brownian bug? (Read 272 times) |
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sinkblot
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boring brownian bug?
« on: Apr 27th, 2004, 10:22pm » |
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Hey - I was just writing a simple object-based faux-brownian motion simulator, and for some reason all of my objects tend towards zero, even though it picks a random direction out of TWO_PI on each .update. Also no matter where the starting coordinates. Any ideas?
here's the code.
//____________object-based drawing engine skeleton
int num=3;
obj[] objs;
void setup(){
size(500,500);
background(255);
objs = new obj[num];
for(int j=0;j<num;j++)objs[j] = new obj(
int(.5*width+1), //_x
int(.5*height), //_y
random(TWO_PI), //r1
float(2) //vel1
);
}
void loop(){
translate(.25*width,.25*height); //this is just to get a clear view of the "tends towards zero" behavior
for(int j=0;j<num;j++) objs[j].update(mouseX,mouseY);
}
class obj{
int x,px,y,py;
float r1;
float vel1;
obj(int _x, int _y, float _r1, float _vel1){
this.x=_x;
this.y=_y;
this.r1=_r1;
this.vel1=_vel1;
this.draw();
}
void update(int newx,int newy){
this.px=this.x;
this.py=this.y;
this.r1=random(0,TWO_PI);
this.x+=this.vel1*cos(this.r1);
this.y+=this.vel1*sin(this.r1);
this.draw();
}
void draw(){
line(this.x,this.y,this.px,this.py);
}
}
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TomC
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Re: boring brownian bug?
« Reply #1 on: Apr 27th, 2004, 11:58pm » |
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Try using floats for x,px,y,py? I think you are losing accuracy every time you add small floats onto your ints.
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sinkblot
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Re: boring brownian bug?
« Reply #2 on: Apr 28th, 2004, 1:37am » |
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perfect, thanks. Thought it was something obvious I was missing.
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