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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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