...create a simple ascending/descending series of values

wnovotny

My aim would be to create a counter, which starts at 0, counts up to 10, then down again to 0, and again starts from the beginning. Somehow i can not figure out how to do that:

int countdown =0;
int seconds, seconds2, startTime;

void setup() {



    startTime = millis()/1000 + countdown;
}

void draw() {

  seconds = startTime + millis()/1000;

    if (seconds > 10)    seconds = startTime - millis()/1000;
    if (seconds < 0)    seconds = startTime + millis()/1000;

    println (seconds);
}

GoToLoop

https://Forum.Processing.org/two/discussion/23846/time-delay-in-python-mode#Item_11

http://Bl.ocks.org/GoSubRoutine/1a0d21828319cf18fecf44101764bd60

jeremydouglass

Conceptually your counter is a bouncing ball. Just like a ball might have a direction vector, and any collision with a wall causes the vector to switch direction....

int x = 0;
int xstep = 1;
void setup(){
  frameRate(4);
}
void draw(){
    if (x >= 10){
      xstep = -1;
    } else if (x <= 0){
      xstep = 1;
    }
    x = x + xstep;
    println(x);
}

This will "bounce."

wnovotny

Yes, perfect! Bouncing-Ball, have not thought about that!

wnovotny

...now thinking further, would it be possible to increase the "limit" (in this case 10) always with 1, if reached? f.e. in the 2nd pass to 11, the 3rd pass to 12,...

Chrisir

sure in line 7 replace 10 with upperBound

After line 8 say upperBound++;

Chrisir

Before setup ():

int upperBound=10;

wnovotny

thank you, actually simple. i think i'm starting to understand loops...

wnovotny

i "remapped" the number-range starting at 90, counting up and down. now i wonder how to set limits, f.e. at 130 (50 when counting down), where the loops resets to the starting position. or even better, shrink the range again down. i guess it is another if situation inside the existing one, or?

int x = 90;
int xstep = 1;
int upperBound = 91;
int lowerBound = 89;

void setup(){
  frameRate(4);
}
void draw(){




    if (x >= upperBound){
      xstep = -1;
      upperBound++;
    } else if (x <= lowerBound){
      xstep = 1;
      lowerBound--;
    }
    x = x + xstep;
    println(x);
}

Chrisir

That's right

In line 16 you see ++

replace this by upperBound += upperBoundStep;

Then similar to line 14 say

if (upperBound> 130)

upperBoundStep = -1;

wnovotny

thanks for your fast answers! i don't understand it completely:

int x = 90;
int xstep = 1;
int upperBound = 91;
int lowerBound = 89;
int upperBoundStep;

void setup(){
  frameRate(8);
}
void draw(){



 if (x >= upperBound){
      xstep = -1;
      upperBound += upperBoundStep;

     if (upperBound > 130){
      upperBoundStep = -1;} 


    } else if (x <= lowerBound){
      xstep = 1;
      lowerBound--;
     }
    x = x + xstep;
    println(x);
 }

Chrisir

Basically the upperBound value dows the same as the x value:

It behaves like a ball that gets reflected

Chrisir

In line 5

upperBoundStep=1;

upperBound changes very very slowly at the moment, only when x touches it (line 14-16)

Chrisir

int x = 90;
int xstep = 1;

int upperBound = 91;
int lowerBound = 89;

int upperBoundStep=8;

int i; 

void setup() {
  //  frameRate(8);
  size(1000, 800);
}

void draw() {

  if (x >= upperBound) {

    xstep = -1;
    upperBound += upperBoundStep;
    x=upperBound-1; 

    if (upperBound > 130) {
      upperBoundStep = -1 * abs(upperBoundStep); // always neg 
      upperBound=130;
    } else if (upperBound < 93) {
      upperBoundStep = abs(upperBoundStep); // always pos
      upperBound=93;
    }
    //
  } else if (x <= lowerBound) {
    xstep = 1;
    lowerBound--;
  }

  x = x + xstep;

  println(x);
  stroke(255, 0, 0);
  point(i, x) ; 

  stroke(0, 0, 255);
  point(i, upperBound) ; 

  stroke(0, 255, 2);
  point(i, lowerBound) ; 

  i++;
}

Chrisir

or use sinus

float x ;
int xstep = 1;

int upperBound = 91;
int lowerBound = 89;

int upperBoundStep=8;

int i=0; 

float radius=120; 
float radiusAdd=-.1; 

float x1 = 0; 
void setup() {
  //  frameRate(8);
  size(1600, 800);
}

void draw() {
  x1=x; 
  x = sin(radians(i*15)) * radius + height/2; 

  println(x);
  stroke(255, 0, 0);
  point(i, x); 
  line(i, x, i-1, x1);


  //stroke(0, 0, 255);
  //point(i, upperBound) ; 

  //stroke(0, 255, 2);
  //point(i, lowerBound) ; 

  i++;

  radius+=radiusAdd;
  if (radius<48) 
    radiusAdd=.1;
  else if (radius>88)
    radiusAdd=-.1;
}