Actuate Back Easing Bug

[sundaefactory]

I think there is a bug with the actuate lib used in Stencyl

The current code in Back.hx, line 86 is

Code: [Select]

public function calculate (k:Float):Float {
   if ((k /= 0.5) < 1) return 0.5 * (k * k * (((s *= (1.525)) + 1) * k - s));
   return 0.5 * ((k -= 2) * k * (((s *= (1.525)) + 1) * k + s) + 2);
}

public function ease (t:Float, b:Float, c:Float, d:Float):Float {
   if ((t/=d/2) < 1) return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b;
   return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b;
}

The "s*=" is not right because s is also used in the same expression

This code is working:

Code: [Select]

public function calculate (k:Float):Float {
   var m:Float = s * 1.525;
   if ((k /= 0.5) < 1) return 0.5 * (k * k * ((m + 1) * k - m));
   return 0.5 * ((k -= 2) * k * ((m + 1) * k + m) + 2);
}

public function ease (t:Float, b:Float, c:Float, d:Float):Float {
   var m:Float = s * 1.525;
   if ((t/=0.5*d) < 1) return 0.5 * c * (t*t*((m+1)*t - m)) + b;
   return 0.5 * c * ((t-=2)*t*((m+1)*t + m) + 2) + b;
}


[captaincomic]

Thanks for the patch. If it's a bug in actuate it would be best to report it here: https://github.com/openfl/actuate
When the bug is fixed upstream, we can update our version of the lib.

Anyway, could you describe what is not working with the current code?

• Status changed from New to Need Info
• Tags added: openfl

[sundaefactory]

ok, I will report it on actuate directly

about the bug, in the expression

Code: [Select]

0.5 * ((k -= 2) * k * (((s *= (1.525)) + 1) * k + s) + 2);s is multiplied by 1.525 during the evaluation of a first part and instead of evaluating the original s value in the second part, it's the multiplied value

I just correct the bug by introducing a local variable holding the multiplied value

[captaincomic]

What I meant is, is it not moving as expected? Wrong direction? To fast/slow?

[sundaefactory]

I think you have nothing to expect from this code, the result can be far from the expected value. For example I wanted to use for a slight grow on a small actor and the scale become so big, the actor was bigger than the screen.

[captaincomic]

Tbh, I don't see a problem with it. Could you attach a test game?

• Tags added: abandoned
• Status changed from Need Info to Closed

• abandoned
• openfl