Calculation for variables in D. Shiffman book "Learning Processing"

Processing Beginners
1

I’m trying to get a better understanding on how Dan Shiffman drew his raindrop shape via the variables below AND the starting y position.

Any help is most appreciated!

Text in bold placed next to the 3 areas in question.

class Drop{
  float x, y;
  float speed;
  color c;
  float r;
  
  Drop(){
    r = 8;
    x = random(width);
    y = -r*4;

for y above, does this mean -8*4 is: y = -32?

    speed = random(1, 5);
    c = color(50, 100, 150);
  }
  
  void move(){
    y += speed;
  }

In the move() function, with the y set at -32 that becomes -32 += speed?
I think my interpretation of y must be wrong?
```

void display(){
    fill(c);
    noStroke();
    for (int i = 2; i < r; i++){
      ellipse(x, y+i*4, i*2, i*2);
    }
  }

**And finally, in ellipse, for y position and w, h: **
**1/ how do you get the raindrop shape if both w and h are the same variable **
2/ i’m not fully understanding the y position calculation

1 Like
2

try to change 2 and 4 in the ellipse and 4 at the constructor with something bigger, you will start to understand how it works. plus, give it some alpha to the circle

Screenshot%20from%202019-05-16%2003-49-06
Screenshot%20from%202019-05-16%2003-49-061366×768 47.2 KB

you wouldnt want the drop instantly shown on the screen, so you should start to draw the drop at minus y axis

3 Likes
3

Thank you @humayung! That was helpful changing the alpha and numbers in ellipse to better visualize.
And I understand the y position now! :slight_smile:

1 Like