How to accelerate ?

General Discussion
1

I have a car and I would like to be able to press arrow_up.

When I press arrow_up my car should go forward and accelerate until it reaches it highest speed.

How ???

Please post code, do not send me to the examples in Panda.

Thank you.

2

Just move forward according to current speed, and add to that speed so it go’s faster next time the function is called:


from pandac.NodePath import NodePath
from direct.gui.DirectGUI import *

# this class will inherrit functions from DirectObject and NodePath,
# not nescesery for the car stuff, but I just find it practical.
class Car(DirectObject,NodePath):

    def __init__(self,car):
        # initialize the NodePath with the car node
        NodePath.__init__(self,car.node())
        # lets set some settings on the car
        self.speed = 0 # current speed
        self.maxSpeed = 60.0 # maximum speed
        self.acceleration = 0.3 # acceleration rate

   def moveForward(self):
        # cap the speed
        if self.speed < self.maxSpeed:
            if self.speed + self.acceleration > self.maxSpeed:
                self.speed = self.maxSpeed
            else:
                # add to the speed, each frame                
                self.speed += self.acceleration

        # move a certain distance with current speed
        dist = self.speed/10            
        angle = self.getH()*math.pi/180.0
        dx = dist*math.sin(angle)
        dy = dist*-math.cos(angle)
        self.setPos(self.getX()+dx,self.getY()+dy,self.getZ())
3

Now the car accelerates… thank you.

How about giving the effect of de-accelerating until it reaches speed of 0 ?

4

Thanks for the code, Yellow :slight_smile:

Probine: How about finding that out on your own? Now with the ACCEL-code it should be easy to write the DE-ACCEL-code on your own :frowning:

Questions like this might be the later reason why others won’t get answers on simple questions they have really tried hard to solve on their own…

Regards, Bigfoot29

5

No problem, but on your slowing down code, you can figure that one out yourself now. I’m not the one writing your game :stuck_out_tongue_winking_eye: , and this way its best so you can learn how to adapt your code.

Hints:
self.breakRate = ?
self.accept(“arrow_up-up”,self.slowDown)

Bigfoot: sure, anytime