physics - Air Resistance/Friction

[Blady]

I got a problem with physics module. There are not air resistance O.o I'm thinking how do this by another way, but it have to be depends on delta time.

For every objects, program perform it:

Code: Select all

local sx, sy = body:getLinearVelocity()
sx = sx * self.worldAirResistance*dt
body:setLinearVelocity( sx, sy )

Data is:
self.worldAirResistance = 0.9

But (0.9 * dt) is a very small value, it make that Air Resistance is too strong.

I need it for my platform game, for player object. Any ideas?

[Robin]

There is a good way to do this, with body:setLinearDamping(damping). You only have to do this once after you create the body.

[Blady]

Ya, it works but horizontally and vertically. And it look funny when Player slowly fall after jump. How do this just in horizontal?

[Robin]

Ya, it works but horizontally and vertically. And it look funny when Player slowly fall after jump. How do this just in horizontal?

Well, I think you can adjust gravity to pull stronger, so on the whole it seems like before.

[ghostwriter]

If you want to calculate drag effects manually and not use the method Robin suggested, the correct way would probably be to calculate it by means of Force, not by directly manipulating the Velocity.

Code: Select all

local sx, sy = body:getLinearVelocity()
local fx = -sx * self.worldAirResistance -- the drag *force* is opposite and proportional to the velocity
body:applyForce(fx, 0)