Hi,

with risk to be banned from this forum, because of spamming with questions,  I dare to ask one more (and unfortunately most surely not last one)


I want to make a full 360 degrees spin in lets say 3 seconds.

I cant figure out how to define the time in relation to rotation.

Code:

float time = 3000;

if(time>0)
{
 for(int i = 0; i<time; i++)
  {
  angle = (angle*i/time+1)%360;
 
 fill(255,255,0);
 rotate(radians(angle));
 rect(100,0,10,10);
   }
 time --;
}


 

?

Well.... huh    where should I start...

I`m working on a project for my studies. I want to make an app that does the following:

By clicking and dragging the user creates a new sphere with centerpoint at where the mouse has been clicked and  a radius equals to the dragged distance.

The sphere has a certain speed at birth. If this speed is more then a certain threshold, it gets linearly accelerated to a maximum speed, where the rings of the sphere start to dissolve (because of the speed). And vice verca - if the speed at birth is lower then the threshold point, it gets decreased until it hits the minimum speed, where the rings also dissolve. The thing with the colors you already know

OH! oh ! there`s the light! While explaining this to you now, I`ve just spotted a logical/thinking problem myself....

Let me look if I can change my implementation, and if not I`ll continue my storytelling
Eventually it should start looking hopefully a bit like this :
http://www.flickr.com/photos/alexposada/sets/72157623578136140/
with the difference, that the spheres are not concentric.  


MORAL: always ask the right and SIMPLE questions

I guess I have to re-write everything using vectors

10 days I`ve been tweeking on this, and now I have to start over.

Lets see if I get it working until Wednesday


Or before I invest the last 2 days until the deadline, I`d better ask:

Using Vectors, could I influence the position and the speed of the point within the formula for Sphere that I`m using

Code:

  
   void drawSphere()
  {
    for(int i=1; i<wRings; i++)
    {
	float phase = i*1./wRings;
	ringCenterY = (sin(phase*PI+HALF_PI)*.5+.5)*radius;
	ringSizeX = sin(phase*PI)*radius/2;
	ringSizeY = ringSizeX/4;
	drawRing();
    }
  }

  void drawRing()
  {
    noStroke();

    for(int i=0; i<hRings; i++)
    {
	float phase = i*slice/hRings-angle;
	x = ringCenterX + ringSizeX*cos(phase*TWO_PI);
	y = ringCenterY + ringSizeY*sin(phase*TWO_PI);    

	pointSize = abs(sin(phase+angle)*TWO_PI);

	float colorShifter = speed*100;

	float cRed = 255*colorShifter;
	float cBlue = 255*(1-colorShifter);
	//  println("RED: " + cRed + "BLUE: " + cBlue);
	fill(cRed,255,cBlue);
	ellipse(x,y, pointSize,pointSize);
    }
  }
 

May be also color ?

sorry, but i just cant follow your thoughts here.
i cant see what the problem is and how this should be solved by using vectors now...

as far as i understood your programm i dont see a reason to use vectors now...

Code:

PVector ring, radius;
PVector angle, acceleration, speed;
PVector timeVector;

float time;
float  speedMax, speedMin;

void setup()
{
  size(500,500);
  smooth();
  noStroke();
  ring = new PVector(0,0);
  radius = new PVector(200,50);
  angle = new PVector(PI,PI);


  speedMax = 1;
  speedMin = 0.1;
  
}


void draw()
{
  fill(0,10);
  rect(0,0,width,height);
  translate(width/2,height/2);
  drawRing();
  rotateRing();
  //println(ring.x + " " + ring.y);
}


void drawRing()
{
  pushMatrix();
  for(int i=0; i<200; i++)
  {
    
    float phase = i*1./200;
    float pointSize = abs(sin(phase)*TWO_PI);
    
    fill(255,0,155);
    ring.x = mouseX + radius.x*cos(radians(angle.x));
    ring.y = mouseY + radius.y*sin(radians(angle.y));
    ellipse(ring.x,ring.y,pointSize,pointSize);  
  }
   popMatrix();
}

void rotateRing()
{  
   for(int i=0;i<360;i++){
     
    time = millis();
    acceleration = new PVector(time,time);
    acceleration.normalize();
    acceleration.mult(0.01);
    
    
    angle.add(acceleration);
    ring.add(angle);
   }
    
}


 

Now I just have to figure out, how to make an acceleration/deceleration to max or min speed. I guess I need a parameter for the acceleration.mult(p) that gives me a relation to .... speed over time, may be?
Any ideas?


never give up hope!