Setting a value once by turning off a boolean doesn't work

Processing Beginners
1 
float x1 = random(50, 450);
float y1 = random(50, 450);

int size1 = 100;

float inc1X = 3;
float inc1Y = 3;


float x2 =x1;
float y2 = x1;

int size2 = 50;

float inc2X = 3;
float inc2Y = 3;

boolean place1 = true; 





void setup () {
size(500, 500);	
	
}

void draw () {
	
	if (place1 = true) { //supposed to only work once
		float x2 =x1;
float y2 = y1;
		place1 = false;
	}
	
	background(255);
	rectMode(CENTER);
	
	fill(120);
	rect(x1, y1, size1, size1);
x1+=inc1X;
	y1+=inc1Y
	
	if (x1>width-size1/2) {
		inc1X = inc1X * -1;
	}
	
	if (x1<size1/2) {
		inc1X = inc1X * -1;
	}
	
	if (y1>height-size1/2) {
		inc1Y= inc1Y * -1;
	}
	
	if (y1<size1/2) {
		inc1Y = inc1Y * -1;
	}
	
	
	
	
	fill(255);
	rect(x2, y2, size2, size2);
	x2+=inc2X;
	y2+=inc2Y
	
}

My code is supposed to set the little square’s position only once to the big square at the beginning, but does it every frame. Can someone help me?

2
2 Likes
3

Hmm, I forgot that. I changed it to this:

if (place1 == true) {

Still doesnt work though. Now the rect completely disappears.
I tried to print the values x2 and y2 and im getting undefined

1 Like
4

Not correct to repeat the word float here

Delete both words float

2 Likes
5

Hello,

An important topic:

:)

2 Likes
6

An old programing trick to avoid the confusion of assignment and equality testing is to invert the order of the test:

> if (true == myBoolean) doSomething();

Since you true can’t be assigned a value, this will always throw an error if you get it wrong.

7

A much better approach is to never directly check for the keywords true & false at all.

Rather just use the boolean variable itself inside if () {} w/o comparing it to anything.

Instead of if (myBoolean == true) {} just shorten it to just if (myBoolean) {}.

And instead of if (myBoolean == false) {} prefix the variable w/ the logical not operator !:
if (!myBoolean) {}.

1 Like