Easy Pattern ... needs some fixing

Programming Questions

swift0190

Easy Pattern ... needs some fixing

in Programming Questions • 10 months ago

Hey guys,

On my way to university i wrote a little pattern program, which i want to be able to be configured with a GUI later on. But atm i am stuck on the speed paramater. As soon as i want to change speed settings inside my integer the whole progress isn't working anymore.

Here's the Code:

int x = 0;
int y = 0;
int speed = 40;
int versatz = 5;

void setup() {
size (600, 600);
smooth();
background (80);
noStroke();
}

void draw () {

x = x + speed;

fill (random(255), random(255), random (255), 100);
ellipse (x, y , 40, 40);

if (x >= width) {
    speed = speed * -1;
    y = y + versatz;
}
    if (x <= 0) {
      speed = speed * -1;
      y = y + versatz;
}

if (y >= height) {
versatz = versatz * -1;
save("picture1.tif");

}

if (y <= 0) {
versatz = versatz * -1;

}

}

I hope you find the mistake ... i tried so many versions so far that i just didn't know where else to go. It's just a logical error i think.

glad to hear some new perspektives

cheers
swift

Replies(4)

Chrisir

Re: Easy Pattern ... needs some fixing

10 months ago

this....

reason was (approx.) that you checked x and y for <= 0 instead of
for < 0.
Since both are 0 at the start (line 1+2) this gets immediately true.

It's a little more complicate than this but dunno.

int x = 0;
int y = 0;
int speed = 60;
int versatz = 5;
void setup() {
size (600, 600);
smooth();
background (80);
noStroke();
}
void draw () {
x = x + speed;
fill (random(255), random(255), random (255), 100);
ellipse (x, y, 40, 40);
if (x >= width) {
speed = abs(speed) * -1;
y = y + versatz;
}
if (x < 0) {
speed = abs ( speed );
y = y + versatz;
}
if (y >= height) {
versatz = versatz * -1;
save("picture1.tif");
}
if (y < 0) {
versatz = versatz * -1;
}
}

swift0190

Re: Easy Pattern ... needs some fixing

10 months ago

Thank you so much!

Just one more thing, what does that "abs" do, would be nice to know since i will be working with that code in the future?

Thanks again for helping out a newbie =)

cheers

Chrisir

Re: Easy Pattern ... needs some fixing

10 months ago

abs gives the absolute of a value
(no minus sign in front)
and always returns a positive number.

I tend to use it because in some circumstances
the line (e.g.)

if (y >= height) {
versatz = versatz * -1;

applies twice, then it would still go in the wrong direction.
It toggles fast between -5 and 5 e.g.

Hence it is better to use

versatz = abs(versatz) * -1;

this is always -5.

So it's reliable and stable leading your pattern upwards again
and can't stutter at the lower border of the screen.

BTW
BtW even with <=

if (y <= 0) {

combined with

versatz = abs( versatz );

it works imho.
So versatz = abs( versatz ); is better than versatz = ( versatz ) * -1;
because with this he goes more and more negative (and changes between 5 and -5.
You can find this by inserting:

println("versatz is now " + versatz + "; and y gets " + y + ".");

For abs()
for abs() see
http://www.processing.org/reference/

swift0190

Re: Easy Pattern ... needs some fixing

10 months ago

Thank you so much, you're the best!!!

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