extends MeshInstance3D

var mat: StandardMaterial3D
var ang: float = 0.0

# Called when the node enters the scene tree for the first time.
func _ready():
	mat = StandardMaterial3D.new()
	mat.albedo_color = Color(0, 1, 0, 0.5)
	mat.cull_mode = BaseMaterial3D.CULL_DISABLED
	mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
	mat.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
		
	mesh = ImmediateMesh.new()


func _process(delta):
	var x0: float = 0.0
	var y0: float
	var z0: float
	var h: float = 5.0

	mesh.clear_surfaces()
	mesh.surface_begin(Mesh.PRIMITIVE_TRIANGLES, mat)
	mesh.surface_set_color(Color.WHITE)
	
	y0 = h * sin(deg_to_rad(ang))
	z0 = 10.0
	for i in range(1, 20, 1):
		var y1 = h * sin(deg_to_rad(ang + 10 * i))
		var z1 = z0 - 1.5
		mesh.surface_add_vertex(Vector3(x0, y1, z1))
		mesh.surface_add_vertex(Vector3(x0 + 1, y0, z0))
		mesh.surface_add_vertex(Vector3(x0 - 1, y0, z0))
		y0 = y1
		z0 = z1
	
	mesh.surface_end()
	
	ang += 120.0 * delta
	if ang >= 360.0:
		ang -= 360.0