torch.gd

extends SpotLight3D
@export var length: float = 6.0
@export_range(0.0, 1.0, 0.01) var falloff: float = 1.0
@export_range(0.0, 1.0, 0.01) var opacity: float = 0.2
var _cone_mesh: MeshInstance3D = null
func _ready() -> void:
	_cone_mesh = MeshInstance3D.new()
	var cylinder = CylinderMesh.new()
	cylinder.material = build_material()
	_cone_mesh.mesh = cylinder
	_cone_mesh.ShadowCastingSetting.SHADOW_CASTING_SETTING_OFF
	add_child(_cone_mesh)
	update_position()
	update_cone()
func build_material() -> StandardMaterial3D:
	var mat = StandardMaterial3D.new()
	mat.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
	mat.blend_mode = BaseMaterial3D.BLEND_MODE_ADD
	mat.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
	var grad = Gradient.new()
	grad.set_color(0, Color(light_color, opacity))
	grad.set_color(1, Color(light_color, 0.0))
	var grad_tex = GradientTexture2D.new()
	grad_tex.gradient = grad
	grad_tex.fill_from = Vector2(0.0, 0.0)
	grad_tex.fill_to = Vector2(0.0, 0.5 * falloff)
	mat.albedo_texture = grad_tex
	return mat
func update_position() -> void:
	_cone_mesh.rotation.x = PI * 0.5
	_cone_mesh.position.z = length * -0.5
func update_cone() -> void:
	var a = deg_to_rad(spot_angle)
	var b = PI * 0.5
	var c = PI - (a + b)
	_cone_mesh.mesh.top_radius = 0.0
	_cone_mesh.mesh.bottom_radius = length * sin(a) / sin(c)
	_cone_mesh.mesh.height = length