A Calculation Question

FallacyStudios

I was wondering if anyone knows a formula so that when something interpolates down I have another object that is Constrained attribute to grow as it comes down.

So for my boss he is flying up above the screen. I know his X and Y. I have a shadow that is down on the floor that is Constrained to the Boss's X. I want the Y to be Constrained so that as the boss interpolates down that the shadow will grow to a max height of 75 from a starting 3.

Thanks.

Sinequanon

Let's say the boss's max height is 400 (I just chose a number) and his minimum height is 25 (I just chose a number, again).

You have a situation where the shadow would grow linearly (to make things simple), so the size of the shadow is a function of the height of the boss, where when:

Height = 400, Shadow Width = 3, and
Height = 25, Shadow Width = 75.

To find the (linear) equation between two points, you need to use this really simple formula:

Equation of a line = y = mx + b, where m is the slope between the two points, and

m = (y1-y2)/(x1-x2)

Without getting too far into the math here (I'll give you a good link that explains it all), the final equation would be:

y=-24/125x+399/5

Which in GameSalad speak would mean using a Constrain Attribute:

Self.Size.Width -> ((-24/125)*game.Boss Height) + 80, which would give you sample values varying on the boss's height from:

game.Boss Height = 25, Self.Size.Width = 75.2
game.Boss Height = 100, Self.Size.Width = 60.8
game.Boss Height = 250, Self.Size.Width = 32
game.Boss Height = 400, Self.Size.Width = 3

If you really wanted to make sure that the height stayed between 3 and 75, you could also wrap the equation above in a max/min statement:

max(3,min(((-24/125)*game.Boss Height) + 80),75))

My one concern is that GS is sometimes wonky with reporting when using interpolate, so put a display text on the boss to make sure it's properly reporting the self.position.Y to the game engine, but otherwise this should suit you well.

Here's the site I used: http://www.webmath.com/equline1.html

slinky1988

You could put a interpolate attribute in the shadow to grow the the desired height with the same time that it takes the boss to come down.