FBI please do not place me on a watchlist, at least not any more.
This is to add to the confetti drop and confetti cannon “celebrations”. It seems like I will be a part of making a
confetti library.
Set Up
The idea was to make confetti accumulate at the center of the screen in the shape of a ball. This ball
grows to a point where it explodes and rains down virtual confetti.
How
That is the most interesting part. How to do this?
The good thing about writing good code previously is that you can easily add to it.
Open-Closed Principle!
Turns
There was brainstorming how to begin. Initially the thought was to find the center of the screen, which is the correct thought.
Next is to create a circle of confetti in the middle.
This is where the turns came in. I thought creating a radius and then adding a random x value from -r to r, and a random y value from -y to y.
Genius!
But wait, this would make a square not the circle desired.
There were other twists and turns but finally I came to the …
Solution
Now came the flood of previous math classes. Namely the unit circle.
Using the center point, bring in theta and radius.
Find a random angle from 0 to 2 * pi. And find a random number between 0 to r.
Then you can find the x & y components and add it to the center point.
Code
(defmethod -create-confetto :bomb [_ center-x center-y]
(let [max-radius 50
radius (rand-between 0 max-radius)
angle (rand-between 0 (* 2 Math/PI))
delta-x (* radius (Math/cos angle))
delta-y (* radius (Math/sin angle))
now (performance-now)]
(merge-confetto {:last-time now
:start-time now
:kind :bomb
:transform {:position {:x (+ center-x delta-x) :y (+ center-y delta-y)}
:velocity {:x 0 :y 0}
:acceleration {:x 0 :y 0.1}}
:max-ball-radius max-radius
:ball-radius radius})))
Since I already had the previous implemation, and also transform functionality. It was easy to add in what I wanted.
Once I realised what I wanted of course.
Best,
Merl