# This script is an addon for HungryProton's Scatter https://github.com/HungryProton/scatter
# It provides a `Project on Terrain3D` modifier, which allows Scatter 
# to detect the terrain height from Terrain3D without using collision.
# Copy this file into /addons/proton_scatter/src/modifiers
# Then uncomment everything below
# In the editor, add this modifier to Scatter, then set your Terrain3D node

#@tool
#extends "base_modifier.gd"
#
#
#signal projection_completed
#
#
#@export var terrain_node : NodePath
#@export var align_with_collision_normal := false
#
#var _terrain: Terrain3D
#
#
#func _init() -> void:
#	display_name = "Project On Terrain3D"
#	category = "Edit"
#	can_restrict_height = false
#	global_reference_frame_available = true
#	local_reference_frame_available = true
#	individual_instances_reference_frame_available = true
#	use_global_space_by_default()
#
#	documentation.add_paragraph(
#		"This is a duplicate of `Project on Colliders` that queries the terrain system
#		for height and sets the transform height appropriately.
#
#		This modifier must have terrain_node set to a Terrain3D node.")
#
#	var p := documentation.add_parameter("Terrain Node")
#	p.set_type("NodePath")
#	p.set_description("Set your Terrain3D node.")
#
#	p = documentation.add_parameter("Align with collision normal")
#	p.set_type("bool")
#	p.set_description(
#		"Rotate the transform to align it with the collision normal in case
#		the ray cast hit a collider.")
#
#
#func _process_transforms(transforms, domain, _seed) -> void:
#	if transforms.is_empty():
#		return
#
#	if terrain_node:
#		_terrain = domain.get_root().get_node_or_null(terrain_node)
#
#	if not _terrain:
#		warning += """No Terrain3D node found"""
#		return
#
#	if not _terrain.storage:
#		warning += """Terrain3D storage is not initialized"""
#		return
#
#	# Get global transform
#	var gt: Transform3D = domain.get_global_transform()
#	var gt_inverse: Transform3D = gt.affine_inverse()
#	for i in transforms.list.size():
#		var location: Vector3 = (gt * transforms.list[i]).origin
#		var height: float = _terrain.storage.get_height(location)
#		var normal: Vector3 = _terrain.storage.get_normal(location)
#
#		if align_with_collision_normal:
#			transforms.list[i].basis.y = normal
#			transforms.list[i].basis.x = -transforms.list[i].basis.z.cross(normal)
#			transforms.list[i].basis = transforms.list[i].basis.orthonormalized()
#
#		transforms.list[i].origin.y = height - gt.origin.y
#
#	if transforms.is_empty():
#		warning += """Every point has been removed. Possible reasons include: \n
#		+ No collider is close enough to the shapes.
#		+ Ray length is too short.
#		+ Ray direction is incorrect.
#		+ Collision mask is not set properly.
#		+ Max slope is too low.
#		"""