simulating rolling friction with Chipmunk2D for a top-down game about chipmunk2d

[aismann]

Use friction on the body/shape

[VictorQueiroz]

@aismann if you mean to set friction on the player's body shape, I tried that, but it didn't have any effect. I am using cpBodyApplyImpulseAtLocalPoint to apply the impulse and make the player move, am I doing it wrong?

[aismann]

Let me See the source snippet plz
or look on the manual:

cpFloat cpShapeGetFriction(const cpShape *shape)
void cpShapeSetFriction(cpShape *shape, cpFloat value)

Friction coefficient. Chipmunk uses the Coulomb friction model, a value of 0.0 is frictionless. The friction for a collision is found by multiplying the friction of the individual shapes together. Tables of friction coefficients.

[VictorQueiroz]

@aismann I pushed my testing application here so you can check:

https://github.com/VictorQueiroz/Chipmunk2D-TopDown-Test

[aismann]

@VictorQueiroz
I think cpShapeSetFriction() is only working sliding on other shapes. My mistake.

[VictorQueiroz]

@aismann what is the alternative to achieve what I want?

[VictorQueiroz]

@aismann here is the video you asked:

2022-12-29 15-55-56.zip

[VictorQueiroz]

I finally made it. I updated the project I sent you on GitHub. A comment from a guy in Reddit helped me fix it:

I can't read c++ very well, but from what you describe it sounds like you haven't implemented drag yet. I like to implement it like this:

velocity = velocity - (velocity * 0.25 * time.deltaTime)

Velocity in this case is the movement vector of your object. You just lower it by a percentage per second until the movement is so little that it's basically stopped. However, it is good to note that it will never actually stop like this.

You could implement drag a different way, it's really up to your preference.

I gently set it's velocity on every frame:

cpVect vel = cpBodyGetVelocity(body.playable->controlBody);
vel = vel - (vel * 0.25 * dt);
cpBodySetVelocity(body.playable->controlBody, vel);