How to make proper jumping for turing platformer

[Turing BEEESD]

Trying to make a turing platformer game for a projects. Having trouble with the jumping mechanic, ive made a parabola but it only really jumps when on a certian area and dissapears if youre not on there. It also jumpes from below the line on the second jump. Is using a parabola the only way to jump and is their anyway I could make it fully jump without holding the jump button?

Heres

View.Set ("graphics:600;600,offscreenonly,nobuttonbar")
%parabola
var x2 : real := 0
var y2 : real := 0
%center
var x : real := 62.5
var y : real := 37.5
%input
var control : array char of boolean
%box
var boxx1 : int := 50
var boxy1 : int := 25
var boxx2 : int := 75
var boxy2 : int := 50
%Direction
var dx : real := 0
var dy : real := 0
%B
var p1x : int := 500
var p1y : int := 500
var eaten := false


loop

%borders
Draw.FillBox (0, 0, 1000, 1000, green)
Draw.Line (0, 37, 1000, 37, black)


%if below bottom
Draw.FillBox (x div 1, y div 1, (x + 20) div 1, (y + 20) div 1, black)
if Math.DistancePointLine (62.5, 37.5, p1x, p1y, p1x, p1y) < 35 then
eaten := true
end if

x := x + dx
y := y + dy
%%% input %%%
Input.KeyDown (control)

if control ('d') then
dx := 2
dy := 0
elsif control ('a') then
dx := -2
dy := 0
elsif control ('s') then
dx := 0
dy := 0
elsif control ('w') then
x := x + .4
y := -0.3 * (x - 100) ** 2 + 100

delay (30)
Draw.FillBox (x div 1, y div 1, (x + 20) div 1, (y + 20) div 1, black)

%Bottom

elsif Math.DistancePointLine (x, y, -50, 37.5, 1000, 37.5) < 47 then
y := 37.5



end if

View.Update
delay (15)
cls
end loop

[TokenHerbz]

Turing BEEESD @ Thu May 03, 2018 10:27 am wrote:

is their anyway I could make it fully jump without holding the jump button?

just make a function or proc called when you hit your jump key, which will in itself continue the jump provided collision allows/controls allow it