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start rewriting physics to force based model

physics3
nek0 2 months ago
parent
commit
f5782fc935
  1. 77
      src/Physics/Classes/Mass.hs

77
src/Physics/Classes/Mass.hs

@ -9,11 +9,11 @@ class Mass m where
-- | The mass of the mass object.
mass :: m -> Double
-- | Retrieve the acceleration of the mass object.
acceleration :: m -> V2 Double
-- | Retrieve the position of the mass object.
position :: m -> V2 Double
-- | Overwrite the acceleration of the mass object.
accelerationUpdater :: m -> (V2 Double -> m)
-- | Overwrite the position of the mass object.
positionUpdater :: m -> (V2 Double -> m)
-- | retrieve the velocity of the mass object.
velocity :: m -> V2 Double
@ -21,42 +21,35 @@ class Mass m where
-- | Overwrite the velocity of the mass object.
velocityUpdater :: m -> (V2 Double -> m)
-- | Retrieve the position of the mass object.
position :: m -> V2 Double
-- | Overwrite the position of the mass object.
positionUpdater :: m -> (V2 Double -> m)
-- | The update function to let a mass react to gravitational pull.
-- Apply all accelerations before calling the default implementation of
-- this function, since it will add the gravitational pull to already
-- existing accelerations.
gravitate
:: V2 Double -- ^ Vector of gravitational acceleration
-> m -- ^ Original mass object
-> m -- ^ Updated mass object
gravitate g m =
let acc = acceleration m + g
in
accelerationUpdater m acc
-- | Apply acceleration to mass object und thus change its velocity
accelerate
:: Double -- ^ Time step duration
-> m -- ^ Original mass object
-> m -- ^ Updated mass object
accelerate dt m =
let vel = velocity m + ((dt *) <$> acceleration m)
in
velocityUpdater m vel
-- | Apply velocity to mass object and thus change its position
-- Changes in position smaller than around half a pixel per second are ignored.
move
:: Double -- ^ Time step duration
-> m -- ^ Original mass object
-> m -- ^ Updated mass object
move dt m =
let dpos = (dt *) <$> velocity m
-- | Total force acting on a particle in one simulation step
forces :: m -> V2 Double
-- | Overwrite the forces acting on a particle
forcesUpdater :: m -> (V2 Double -> m)
-- | Reset forces vector for the begining of a new simulation step
resetForces :: m -> m
resetForces m = forcesUpdater m (V2 0 0)
-- | Calculate the loads or forces acting on the mass object except for
-- collision forces.
addLoads
:: m -- ^ The mass object
-> V2 Double -- ^ force to be aggregated acting on the particle (e.g.: gravity)
-> m -- ^ Resulting mass object
addLoads m vec =
forcesUpdater m (forces m + vec)
-- | Euler integration updates
updateByEuler
:: m -- ^ The mass object
-> Double -- ^ Time step in fraction of a second
-> m -- ^ Resulting mass object
updateByEuler m dt =
let acc = (/ mass m) <$> forces m
dvel = (* dt) <$> acc
nvel = velocity m + dvel
dpos = (* dt) <$> nvel
npos = position m + dpos
in
positionUpdater m (position m + dpos)
positionUpdater (velocityUpdater m nvel) npos

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