CODEWITHSUNDEEP
c#unity-game-engine2dgame-physics
Muhammad Nihad
Muhammad Nihad

Reputation: 115

Increase the time of the character being at the peak of the jump

I am working on a character controller for a 2d-platformer I am using Unity3D to implement it using my own physics (not the standard physics and the RigidBody2D component), anyway I finished it mostly but the problem is the jump, it is satisfying but I want the character to stay a little bit longer in the air when it reaches the peak of the jump, but without using a timer or so, what I mean by that, I want the character to raise slower when it gets close to the jump peak, so the jump curve gets wider.

The way I handle the velocity and movement is so: - I have a Vector2 velocity that represent the current velocity, it is set each frame depending on the current state of the character(Walking, Running, Idle,...) - I have a float gravity which is a fixed float representing the gravity - When the player jumps, I set its velocity.y to jumpVelocity and each frame, I subtract (gravity * Time.DeltaTime) from it.

The jump curve I get:

enter image description here

The jump curve I want:

enter image description here

Anyway easy way (Changing a factor or adding a variable or so) to achieve that without rewriting 50% of my code? Thanks in advance :)

With (gravity*time^2) as mentioned in the comments:

enter image description here

Upvotes: 0

Views: 1928

Answers (3)

Muhammad Nihad
Muhammad Nihad

Reputation: 115

There is a simple solution that I implemented after changing the code a little bit... expanding on the method of Sebastian Lague (An amazing youtuber), it is possible now to scale the curve horizontally (using timeToJumpApex variable) and vertically (using maxJumpHeight variable):

gravity = -(2 * maxJumpHeight) / Mathf.Pow(timeToJumpApex, 2);
maxJumpVelocity = Mathf.Abs(gravity) * timeToJumpApex;

This method will also calculate the gravity for you... Anyway my jump still doesn't feel that good yet, but that is not related to maths and physics equations nor to implementation problems, but as it turned out this curve is not the best one for a platformer jump...

Edit: The way I apply gravity to velocity didn't change, so:

velocity += (gravity * Time.deltaTime);

Upvotes: 0

dasmy
dasmy

Reputation: 597

The time until reaching the peak is computed by setting 

jumpVelocity - time * gravity = 0,

i.e.

time = jumpVelocity / gravity.

If you want your character to stay in the air for a longer time, you can increase the jumpVelocity or decrease the gravity.

However, this also leads to higher jumps.

The height of the jump is (https://en.wikipedia.org/wiki/Linear_motion#Equations_of_kinematics)

height = jumpVelocity * time - gravity/2 * time^2.       (*)

With time from above, you get 

height = jumpVelocity^2 / (2*gravity),

which with the time above yields

time = 2*height / jumpVelocity.       (**)

Thus, to e.g. jump twice as long while keeping the height constant, you have to multiply jumpVelocity by 0.5 due to (**) and gravity by 0.25 due to (*).

Upvotes: 1

Matthias Bö
Matthias Bö

Reputation: 459

You should change the ratio of horizontal and vertical velocity. So you could either leave gravity and jump velocity untouched and increase the horizontal velocity, or decrease both gravity and jumping velocity (proportionally).

Upvotes: 0

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