Jumping Platform Characters

[jazz_e_bob]

What is the easiest way to test if an actor is standing on a platform?

The actor should only be able to jump if he is standing on the platform - not already in the air.

jazz

[ingsan]

Hi, how are you ?

On your Platform actor (On KeyDown > Script), write :

if(yvelocity == 0)
{
Jump;
}

Heh, mate, we're still on the Move

[jazz_e_bob]

Hi Ingrid.

I am well.

Had a major system crash recently though. Lost a few hours work on microfooty and a few days to rebuild my computer. Working better than ever now though.

Glad to hear you are keeping busy. You guys do such amazing work.

The only problem with what you said is that ( yvelocity == 0 ) at the peak of a jump too.

[ingsan]

How come there is a yvelocity = 0 at peak of jump ? Do you have gravity on Draw Actor ? Did you put yvelocity = 0 at jump peak so that you obtain gravity ? If that is the case, I have probably a better way of doing that ...

Anyway, for your problem, you can use a variable.
On Collision with Platform, jump = 0;
On CollisionFinish with Platform, jump = 1;
So, onKeyDown, if ( jump == 0 ), Jump Action;

[ingsan]

Here's what i do for a platform character :

You have two actors : Batman and Ground

Batman
Add Event KeyDown[UP]
Add Script and write :

yvelocity = -9;

Add Event DrawActor
Add Script and write :

yvelocity = yvelocity + 1;

Add Event onCollision with TopSide of Ground ( Repeat YES )
Add Script and write :

yvelocity = 0;

You get a Smooth and gradual jump and gravity

[jazz_e_bob]

Cool.

Thanks for the tip.

[ingsan]

you're welcome

[Snowfly]

hi ingsan, i tried your solution. it works fine, except that there is still a very small chance that the player can double-jump (when at the peak of a jump). this is what jazz-e-bob was mentioning.

is there a more elegant solution?

[jazz_e_bob]

http://www.game-editor.com/forum/viewto ... atform+guy

This uses a second actor to detect the platform.

[Snowfly]

hi jazz-e-bob, platform guy is pretty cool. i'm digging into your code now.

the solution i tried was to set a global variable 'int onGround = 0' (my character starts in the air) and setting it to 'onGround = 1' whenever the player touches the ground. When the player presses the jump button, onGround is set to 0.

This pretty much kills the double-jump, but the character is still able to jump when you simply walk off a platform. I tried adding a collision finish script to set onGround to 0 when the character walks off a platform, but it didn't do anything.

another bug i'm working around is preventing the character from 'sticking' when you push against a wall mid-jump.

[jazz_e_bob]

Good luck!

[Snowfly]

here's my solution for platform guy:

on collision with platform, set parent of event actor to collide object. set parent to 'no parent' on finish collision with collide object. voila!

next i will try to inherit some momentum from the platform.

[jazz_e_bob]

Well done.

I have added this to my demo and will release it with next GE update.

[jazz_e_bob]

Here it is:

http://www.artsystems.com.au/game%20editor/platformGuy.zip

Requires GE 1.3.2

[DilloDude]

You can also see my solution to the double-jump bug.
http://game-editor.com/forum/viewtopic.php?p=7564&highlight=#7564