[Trigger] [Solved] Double Jump ...

[jonhysone]

Hello.

Well, I've been making a Jump system for some mini-game. But I faced some huge obstacle, besides I am bad at Maths.

Now I know I am making no mistakes in the first Jump System. But Seriously how can I make a second mid-air Jump so the player will jump again from the point and height he is at now ?!

This is an example picture of how I want the mid-air jump (Blue graph is the Jump Function, the red one is the mid-air one), I want something like (Move from the blue to the red) smoothly.

Jump and Double Jump Function

I tried to make a Jump System, and also tried to add the Double-Jump thing, but I'd better not show how I had it done, it's a shame that it never works. I just want it to look exactly like the one in XANID's map, unfortunately it's written in vJASS :/... the jump is executed under the formula :

Yet I have no idea how to move from the normal jump formula into the double-jump one lol, the unit always returns onto the ground everytime I executed the Jump once again. (Remember I turned off the normal jump formula and executed the double-jump, it didn't work since I don't even know how to move between formulas).

• Events
  • Time - Periodic Event 0.03
• Conditions
  • Jump_Executed = true
• Actions
  • Set Time_Variable = (Time_Variable + 0.03)
  • Set Player_Height = ( - [squareroot(MAXHeight) - Time_Variable]² + MAXHeight )
  • Animation - Change Footman's Height to Player_Height at rate 0.00

Any math helpers ?

Thanks, and +rep+credits.

 

[Flux]

Here's a detailed explanation on the solution to your problem.

I will derive the equation you will used as well for you to understand
a = dv/dt and v = dy/dt from Physics and using common sense.
and variables are
t₁ = initial time, assumed 0, t₂ = final time
v₁ = initial velocity, v₂ = final velocity
a = constant = -9.8 m/s²
then dy = vdt -> (y₂-y₁) = v(t₂ - t₁)
thus y₂ = y₁ + v(t2₂-t₁)
a = dv/dt -> (v₂-v₁) = a(t₂ - t₁)
v₂ = v₁ + a(t₂) but v = dy/dt
dy₂/dt = v₁ + at₂
y₂ = v₁t + 0.5at₂² + y₁ this is now the formula you used to represent the height of the unit in terms of time and initial velocity. Feel free to choose what you think will result to most realistic acceleration but make sure it is less than zero (negative).

Now if a unit jumps initially from ground, y1 (initial height) = 0, just set v1 = any arbitrary positive value and you need to store that.
I simplified y₂ -> y, t₂ -> t in the equation below
Let's say the the unit jumps with initial velocity of 100 units per second, store that initial velocity to a variable

• set v1 = 100

y = 100*t + 0.5(-50)(t²) + y1 is the equation
Points (height y, time t) of jumping:
(going up)
y = 100*0 + 0.5(-50)(0²) + 0 = 0
y = 100*0.1 + 0.5(-50)(0.1²) + 0 = 9.75
y = 100*0.2 + 0.5(-50)(0.2²) + 0 = 19
y = 100*0.3 + 0.5(-50)(0.3²) + 0 = 27.75
(going down, say t = 2.5)
y = 100*2.4 + 0.5(-50)(2.4²) + 0 = 96
y = 100*2.5 + 0.5(-50)(2.5²) + 0 = 93.75
At this point, the unit jumps mid air (exactly at t = 2.5), then recompute the current velocity
v₂ = v₁ + a(t₂) = 100 + -50*2.5 = -25 then
add a new velocity to the current velocity, let's say 100 again
at this point,

• set v1 = -25 + 100

and your new height equation will be and you need to reset time = 0
y = 75*t + 0.5(-50)(t² + 93.75
y = 75*0.1 + 0.5(-50)(0.1²) + 93.75 = 101
y = 75*0.3 + 0.5(-50)(0.3²) + 93.75 = 114
y = 75*1 + 0.5(-50)(1²) + 93.75 = 143.75
So noticed that the new height begins to rise again and eventually will fall down
y = 75*3.5 + 0.5(-50)(3.5²) + 93.75 = 50

TL;DR your periodic trigger will be something like this

• Set Player_Height = InitialVelocity*Time_Variable + 0.5*(Acceleration_Variable)*(Time_Variable*Time_Variable) + InitialHeight
• Animation - Change Footman's Height to Player_Height at rate 0.00

When unit jumps from ground, any number will do and that number will dictate the jump magnitude

• Set InitialVelocity = 100
• Set InitialHeight = 0

when a unit jumps from mid air

• Set InitialVelocity = 2*InitialVelocty + (Acceleration_Variable)*(Time_Variable)
• Set InitialHeight = Player_Height

Note, you might wanna make that MUI using unit indexer with custom values as array index like
Time_Variabe[], Player_Height[]
Or use a Hashtable or struct per jump instance.

 

[Dr Super Good]

You break the problem into parts by converting the jump into velocity vectors, simulating gravity on them and then applying the difference for the second jump.

Or that is what I would think.

 

[Wietlol]

Double jump....
I assume that when you have one jump, you restrict the user to jump when it is in mid-air.
Remove that restriction and your jump should work... at least if the approach would have been right.

Just re-apply the jump that you have but start with a different (the current) flying height.

 

[jonhysone]

@Flux : Brilliant, I rebuilt my Jump's system (I will Give Credits to you) and its' working good.

@Dr. Super Good : Well, I think Flux' solution does that.

@Wielol : Well, that was actually the problem of the 'never-double-jump-executing' , but yet when It started to work, it looked @{é/! , (The reason was my high Math Knowledge xD).


Thanks to the three of you. FIXED. +rep for everyone.

 

[VicALV]

Derivates