[Snippet] Parabolic Function

Scripts

14 years
edited 8 years
Parabolic function simplified by Spec
Code (jass) Select
library ParabolicMovement

function ParabolaZ takes real h, real d, real x returns real
  return (4 * h / d) * (d - x) * (x / d)
endfunction

endlibrary


I left this function because it allows to understand the formula coefficients...

Code (jass) Select
function ParabolicMovement takes real h, real d, real x returns real
    local real a = -4*h/(d*d)
    local real b = 4*h/d
    return a*x*x + b*x
endfunction


This function takes as a parameters the distance that the parabolic movement should move (d) and the maximum height the projectile will flight (h).

So x is a value between 0 and d, and the function will return the height for that value.

As a side note, if x < 0 or x > d then this function will return negative values.

Here's a picture for a better understanding of the parameters:


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Parabolic movement now taking into account initial and final Z heights.

Code (jass) Select
library ParabolicMovement2

function ParabolaZ2 takes real y0, real y1, real h, real d, real x returns real
  local real A = (2*(y0+y1)-4*h)/(d*d)
  local real B = (y1-y0-A*d*d)/d
  return A*x*x + B*x + y0
endfunction

endlibrary




Notes:

       
  • This function will return the absolute height and therefore this value should be the height you must set to the unit in the function SetUnitFlyHeight()-y0.
  • In order to obtain a proper parabolic shape, "h" must be greater or equal than the maximum value of "y0" and "y1", but anyways, you're free to play with lower values of "h". "h" is the height when x = d/2 but it's not necessarily the maximum height it will reach, the maximum height will be reached when x = -B/2A.
14 years
Nice :D

I love simple libraries like these. :)