KITT without arrays

Patterns and Code
1

@zranger1 got a proof of concept for this going in this thread.

He added:

I took a shot at this today and got something workable. Sorry I’m lazy and didn’t add nice UI controls :wink:

ezgif.com-gif-maker

var tailPct = .6 // length of the tail in 0..1
var t1, shift = 1 - tailPct

export function beforeRender() { t1 = time(.05) }

function pulse(x) {
  var halfsaw = triangle(x - t1) * square(x - t1, .5)
  return max(0, (halfsaw - shift) / tailPct)
}

export function render(index) {
  pct = index / pixelCount / 2
  v = pulse(pct) + pulse(-pct)
  hsv(0, 1, v * v * v)
}

Interestingly, original KITT is about 1.6x faster.

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2

I feel like golfing this could end with a super minimal KITT.

And now I’m curious to see a mapped arrayless KITT too. But the array is otherwise useful (it’s a cheap framebuffer approach, which can be handy for all sorts of stuff) so lots of ways to do the same thing.

3

Ok, golfed mapped arrayless version (with sliders and exports for exploration):

export var tailPct = .6 // length of the tail in 0..1
export var speed = .05
export var pct1
export var pct2

export function sliderTail (v) {
  tailPct = .6 + v/3;
}

export function sliderSpeed (v) {
  speed = v/10;
}

export function render2D(index,x,y) {
  pct1 =  y/2 - time(speed)
  pct2 = -y/2 - time(speed)
  v = max (0,( tailPct - 1 + triangle(pct1) * square(pct1,.5) ) / tailPct )
    + max (0,( tailPct - 1 + triangle(pct2) * square(pct2,.5) ) / tailPct )
  hsv(0, 1, v * v * v)
}

that’s running at 69+ FPS on my v3 with a 16x16 matrix

to compare:
Original KITT runs at 79 FPS
Mapped Array KITT runs at 80 FPS

So the array approach is slightly faster… but… even changing it from v*v*v to v*v adds a frame or 2 back. But still, that’s only a 15% difference in speed. You’ve entirely eliminated any arrays, pure math/waves, so it’s a bit slower but uses MUCH less memory.

1 Like
4

Very nice! No arrays, just math!

1 Like