package physics

import "core:math"

Pacejka96_Params :: [11]f32

DEFAULT_PACEJKA96_PARAMS :: Pacejka96_Params{1.65, 1, 1750, 0, 229, 0.0, 0, 0, -12, 0, 0}

// X is slip ratio percentage [-100, 100] or slip angle in degrees, where positive angle is turning left
// Output is the friction coefficient
pacejka_96 :: proc(b: Pacejka96_Params, x: f32, f_z: f32, s_v: f32 = 0) -> f32 {
	C := b[0]
	D := (b[1] * f_z + b[2]) * f_z
	B := ((b[3] * f_z * f_z + b[4] * f_z) * math.exp(-b[5] * f_z)) / (C * D)
	E := -(1 - (b[6] * f_z * f_z + b[7] * f_z + b[8]))
	s_h := b[9] * f_z + b[10]

	X := x + s_h
	y := D * math.sin(C * math.atan(B * X - E * (B * X - math.atan(B * X))))
	Y := y + s_v
	return Y / (f_z * 1000)
}