Sign in to follow this  

jumping

This topic is 4669 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

When you start the jump, call this function:



void Jump()
{

Player.yspeed = 10;
Player.jumping = true;

}




and when the player is in the middle of a jump:



void HandleJump()
{

Player.y -= Player.yspeed;
Player.yspeed--;

// Check collision.

}









Share this post


Link to post
Share on other sites
well This might sound easy but have you thought a simple quadratic formula?

y=-x^2+3x for instance but instead of X make it time, and after 3 units you'll be at the height of your jump, and just have it so when y=0 and Time is not =0 he will have landed.

Though I'd check that, that was off the top of my head (I unfortunatly don't have graphing software on my computer right now) . Of course that uses Absolute positions. I'm sure you can tweak something like that for gravity for your world.

That makes a simple Mario style Leap.

Or are we speaking of a different sort of jumping? A little more information might be helpful here.

Share this post


Link to post
Share on other sites
sorry for the lack of info, and thanks for trying to help. i have a first person game, and i can't get a jumping formula down. Stompy9999, i don't really get where the player and speed stuff is. i was thinking about something using sine or cosine, but i don't know of any formulas that will have me jump, and while im getting to the top of my jump, start to slow down, then as its going down, start to slow down.

Share this post


Link to post
Share on other sites
If it's a first person 3d game, there is no need to use trigonomotry to jump. All you need to do is increase along the y-axis while jumping and stop jumping when the player collides with something.

Share this post


Link to post
Share on other sites
Quote:
sorry for the lack of info, and thanks for trying to help. i have a first person game, and i can't get a jumping formula down. Stompy9999, i don't really get where the player and speed stuff is. i was thinking about something using sine or cosine, but i don't know of any formulas that will have me jump, and while im getting to the top of my jump, start to slow down, then as its going down, start to slow down.

Stompy9999's solution will do that. When the character begins its jump, it will have a certain vertical speed. Over time, the vertical speed decreases, and at some point it will become zero. That's the top of the jump. The vertical speed continues to decrease, becoming negative (i.e. downward). Eventually he hits the ground and its all over.

Share this post


Link to post
Share on other sites
heres a time based way to jump

x_t = x_0 + v_0*t + 0.5*a_0*t*t
v_t = v_0 + a_0*t

x_0 is the current height
x_t is the new height after time t
v_0 is the current velocity
v_t is the new velocity after time t
a_0 is the acceleration (gravity)
t is how mush time passed

to jump set the velocity (v_0) to some number that is opposite of the acceleration (like v_0 = -10 and a_0 = 15)

Share this post


Link to post
Share on other sites
Quote:
Original post by iedoc
sorry for the lack of info, and thanks for trying to help. i have a first person game, and i can't get a jumping formula down. Stompy9999, i don't really get where the player and speed stuff is. i was thinking about something using sine or cosine, but i don't know of any formulas that will have me jump, and while im getting to the top of my jump, start to slow down, then as its going down, start to slow down.


Here's a simple jump using sine that jumps to a maximum of J pixels. replace i with your jumping counter.

PI=3.14159265
for i=0 to 1 step 0.1
jump=(sin(i*PI)*J)
next

Share this post


Link to post
Share on other sites
The most flexible way to handle jumping comes in two parts:

1) Gravity (i.e. falling) - this'll account for running off the side of platforms and stuff like that too.
2) Upthrust - this'll throw your guy upwards when the player hits 'jump.'

Something you'll need to know for both of those is whether or not the player is 'on the ground' (so you can stop them hitting jump when they're already in midair, and so you know when to stop falling). There are various ways of doing it; one approach I might take is to sample a point X units below the player's feet, and find out whether it's floor or not.

Once you've got that, you can implement gravity:

void Player::ApplyGravity()
{
if(!IsOnFloor())
{
velocity.y += GRAVITY;
}
else
{
velocity.y = max(velocity.y, 0);
}
}

void Player::Update()
{
position += velocity;
}



And when you want to jump:


void Player::Jump()
{
velocity.y = JUMP_SPEED;
}



You'd set JUMP_SPEED and GRAVITY to constants that make sense for your player - they'd have opposite signs, of course (because they're going in opposite directions).

Share this post


Link to post
Share on other sites

This topic is 4669 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this