Learning Processing

Programming Questions

andrew1992

in Programming Questions • 1 year ago

Hello.

I have recently stumbled across processing and have decided to try learn it myself as a first computer language.

What I am currently trying to do is simply have a square and circle appear on a mousePressed but not before. Then upon dragging the mouse (with the square and circle intact) have the circle and only the circle disappear on a mouseRelease, leaving the square. Im trying to sort of replicate a 'drag and drop' action.

Not sure if I should be using all three mouse variables (pressed, drag, released).

Also how do I start the program without the square/circle showing at the start?

For the circle to dissapear I am simply moving it off screen but im sure there is a better way - maybe with booleans or some condition.

Any help or advice is appreciated.

Thankyou.

int circlelocX, circlelocY;
int rectlocX, rectlocY;
boolean release = false;
boolean start = false;
void setup() {
size(350,500);
rectMode(CENTER);
ellipseMode(CENTER);
smooth();
frameRate(60);
}

void draw() {
background(255);
// should use if statement here for start condition???
noFill();
fill(255,0,0);
ellipse(circlelocX,circlelocY,75,100);
noFill();
rect(rectlocX, rectlocY, 75, 100);
}
void mousePressed() {
rectlocX=mouseX;
rectlocY=mouseY;
circlelocX=mouseX;
circlelocY=mouseY;
}
void mouseDragged() {
rectlocX=mouseX;
rectlocY=mouseY;
circlelocX=mouseX;
circlelocY=mouseY;
}
void mouseReleased() {
circlelocX=-1000;
}
//release = true; //How to make the oval disapear only. Leaving the square.

Replies(2)

PhiLho

Re: Learning Processing

1 year ago

That's lot of questions, I will try and answer at least some...
How to make things to disappear (or not to appear on the start)? That's simple in Processing! Just don't draw them...

All the shapes are drawn at each call of draw(), and the background() call just start by erasing the previous frame content.
So, you are right in thinking to use booleans and conditions.
You have a start variable. For consistency, initialize it to true instead of false.
Then, in draw(), you can do:

void draw() {
background(255);
if (start)
return; // Display nothing!
// Remainder of code
}
void mousePressed() {
if (start) {
start = false; // Allow to display stuff
} else {
// Do the dragging thing
}
}

andrew1992

Re: Learning Processing

1 year ago

Thanks!

I think its much better now. What do u think?

Sorry about all the questions originally!

int circlelocX, circlelocY;
int rectlocX, rectlocY;
boolean start = true;
void setup() {
size(350,500);
rectMode(CENTER);
ellipseMode(CENTER);
smooth();
frameRate(60);
}

void draw() {
background(255);
if (start)
return;
noFill();
rect(rectlocX, rectlocY, 75, 100);
fill(255,0,0);
ellipse(circlelocX,circlelocY,75,100);
}
void mousePressed() {
   if (start) {
     start=false;
   }else{
     circlelocX=-1000;
   }
rectlocX=mouseX;
rectlocY=mouseY;
circlelocX=mouseX;
circlelocY=mouseY;
}

void mouseDragged() {
rectlocX=mouseX;
rectlocY=mouseY;
circlelocX=mouseX;
circlelocY=mouseY;
}
void mouseReleased() {
   if (start) {
     start=false;
   }else{
     circlelocX=-1000;
   }
}

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