Sidescroller help with movement

Game Engine Game Engine Support and Discussion
1

Hi,

I am working on a sidescroller in BGE and I need some help with the movement. I basically want movement like in Mario. While in mid-air you can still move, but not jump, and you don’t slide about when moving. I have tried making a python movement script to do this, but I failed: I couldn’t make the character move in mid air to prevent the jumping. I also need it to kind of do the same movement as loc actuators (no damping or whatever it’s called :o), but not to bounce in and out of objects. So does anyone know of a way to do this? It would be a great help to this game.

BTW: I think it’s impossible to do this with logic bricks, so that’s why I’m using python instead.

Many thanks,
HamstaQ

2

My system; DynamiX is rather complex, but I’ve learned some things that may help you discover a solution that works for you.

I prefer to use rayCasts to discern where the ground and walls are; and setLinearVelocity() to move the character. To prevent jumping in mid air; only initiate the jumping script/module if the rayCast detects the ground under the characters feet. I also like to use setLocalPosition() to glue the character to the surface (Instead of letting his feet fall through.)

Hope this helps; for a video demonstration of these features in action, check out my project (see signature) If you would like; I can reduce it to a template that would be somewhat easily applied into your game. I would also have to modify it to 2.6, or 2.5, depending on which you use (I am currently using 2.49) but that wouldn’t take me too long.

3

For ground movement, I’ve also found that setLinearVelocity() works well. However, it seems to ignore gravity. You’ll have to disable it while in midair by means of a rayCast or collision sensor.

As for jumping and midair movement, I suggest applyForce(). It lets you push the character in a desired direction, but still allows gravity to affect the character naturally. Hope this helps.

4

setLinearVelocity() works just fine with gravity; provided you use it like this:

owner.setLinearVelocity([Desired X movement, Desired Y movement, owner.getLinearVelocity(True)[2]],True)

5

[ATTACH]170720[/ATTACH]
Try this. The logic is spaghettied together cause i didnt take the time to clean it up or set it to different states, but I think you can backwards engineer it if you like it.

Maybe limit how far someone can go while movement in air so you dont get a constant exaggerated drift.

6

@Redikann Yeah, the only problem is there’s no gravity control with linV.
@vreksikon, @MCStudios Do you by any chance have an example script for this?

Thanks for the support

7

Never mind. I managed to get it working. I just turned up the friction amount in the material settings.
Here’s the script for movement if anyone’s interested.

############################################
# SIDESCROLLER MOTION SCRIPT
# Matt Evans (HamstaQ)
############################################
import bge
from bge import logic
from bge import events
cont = logic.getCurrentController()
own = cont.owner
x_linv = own.getLinearVelocity()[0]
z_linv = own.getLinearVelocity()[2]

if logic.keyboard.events[events.AKEY] == 2:
    x_linv = -7.5
if logic.keyboard.events[events.DKEY] == 2:
    x_linv = 7.5
if cont.sensors["g"].positive and logic.keyboard.events[events.SPACEKEY] == 1:
    z_linv = 10

own.setLinearVelocity([x_linv, 0.0, z_linv], 1)

I don’t know how to get input from the arrow keys, so I have to use A and D instead. How do I get input from the arrow keys?

8

From the API:

bge.events.LEFTARROWKEY
bge.events.RIGHTARROWKEY
bge.events.DOWNARROWKEY
bge.events.UPARROWKEY