func (c *Physics) Integrate(data *structs.Data, duration float64) {
if data.InvMass <= 0 {
return
}
if duration <= 0 {
panic("Duration cant be zero")
}
// update linear position
data.Position.Add(data.Velocity.Multiply(duration))
// Work out the acceleration from the force
resultingAcc := data.Acceleration.Clone()
resultingAcc.Add(data.Forces.Multiply(data.InvMass))
// update linear velocity from the acceleration
data.Velocity.Add(resultingAcc.Multiply(duration))
// impose drag
data.Velocity = data.Velocity.Multiply(math.Pow(data.Damping, duration))
// look in the direction where you want to go
data.Orientation = data.Velocity.ToOrientation()
// data.Orientation += data.Rotations * duration
// clear forces
c.Data.Forces.Clear()
}
func NewPhysics(data *structs.Data) *Physics {
data.MaxVelocity = 300
data.MaxAcceleration = 100
p := &Physics{
Data: data,
PrevData: structs.NewData(),
CollisionGeometry: &Circle{
Position: data.Position,
},
}
p.PrevData.Copy(p.Data)
if data.Width > data.Height {
p.CollisionGeometry.(*Circle).Radius = data.Width / 2
} else {
p.CollisionGeometry.(*Circle).Radius = data.Height / 2
}
return p
}