GodotComponentTest/utils/SpringDamper.gd

42 lines
1.1 KiB
GDScript
Raw Normal View History

2022-08-19 18:48:54 +02:00
# Based on: allenchou.net/2015/04/game-math-precise-control-over-numeric-springing/
extends Object
class_name SpringDamper
var omega
var zeta
# Called when the node enters the scene tree for the first time.
func _ready():
pass # Replace with function body.
func _init(osc_freq:float = 1.0, osc_red:float = 0.1, osc_red_h:float = 1.0):
assert (osc_red > 0.001 and osc_red < 0.999)
omega = osc_freq * 2 * PI
zeta = log(1.0 - osc_red) / (-omega * osc_red_h)
print ("omega: ", omega, " zeta: ", zeta)
func calc(x, v, xt, h:float):
var f = 1.0 + 2.0 * h * zeta * omega
var oo = omega * omega
var hoo = oo * h
var hhoo = hoo * h
var det_inv = 1.0 / (f + hhoo)
var det_x = f * x + h * v + hhoo * xt
var det_v = v + hoo * (xt - x)
return [det_x * det_inv, det_v * det_inv]
2022-08-19 19:13:39 +02:00
func calc_clamped_speed(x, v, xt, h:float, s_max:float):
var res = calc(x, v, xt, h)
var x_new = res[0]
var vel_new = (x_new - x) / h
var speed_new = vel_new.length()
if speed_new > s_max:
vel_new = (vel_new / speed_new) * s_max
x_new = x + vel_new * h
return [x_new, vel_new]
return res