[2D Jumping Sprite Animation [FIXED]]

GabrielBailey74

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[2D Jumping Sprite Animation [FIXED]]

« on: 2012-01-11 15:43:30 »

So as the title says i'm triyng to create a simple jumping animation for my 2d RPG, instead of just having left,right,up,down movements i'd like left, right, and jump.

At the moment the only variables to tell/change a players position are:
public int absX;
public int absY;

Now I know i'm going to need some other variables + forumlas, such as Dx, Dy, but if someone could point me in the direction on how to go on this, it would be much appreciated.
At the moment i just made a simple method called jump(), which (absY--) = (Up actually), 15 times, and when that characters height has raised 15 times, than i would lower it back to -15, (flat at the floor), so it looks like a animation.
But I really don't like the way that that looks O_o.
If someone could help me please! Shocked

ra4king

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Re: [2D Jumping Sprite Animation]

« Reply #1 on: 2012-01-11 17:43:55 »

Well the variables that are needed are gravity and yVelocity.
Gravity is a constant which you should tweak to your heart's content to get it right. Let's make gravity 500 pixels per second.
The Y velocity will be 0 when the player is not jumping, but as soon as you hit the spacebar, you set it to a desired vertically moving speed. Let's go with -300 pixels per second as the initial velocity.

Now every tick, you will add the yVelocity multiplied with the delta to the Y variable. Then you will add the gravity multiplied with the delta to the yVelocity. This is applying gravity your velocity and then applying the velocity to your position.

BTW: You should change absX and absY to doubles.

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private final double gravity = 500;

public void update(long deltaTime) {
    double delta = deltaTime / 1000.0;
    
    if(spaceBarIsPressed)
        yVelocity = -300; //Going up 300 pixels per second.
    
    absY += yVelocity * delta;
    yVelocity += gravity * delta;
}

-Roi
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GabrielBailey74

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Owner of Elite Demons R.I.P

Re: [2D Jumping Sprite Animation]

« Reply #2 on: 2012-01-11 17:56:46 »

Ah, I figured it out, perfectly.
Thanks m8, thread closed.

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GabrielBailey74

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Posts: 157
Medals: 2

Owner of Elite Demons R.I.P

Re: [2D Jumping Sprite Animation [FIXED]]

« Reply #3 on: 2012-01-21 19:16:02 »

Thanks about the BTW on turning my ints to doubles for player positioning, just now looking into deeper detail on a Double, thanks m8.

ra4king

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Posts: 3131
Medals: 195

I'm the King!

Re: [2D Jumping Sprite Animation [FIXED]]

« Reply #4 on: 2012-01-21 19:18:20 »

Glad to help

-Roi
Doodle Jump online!
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