feat(plugin): add terrain3d plugin installation

addons/terrain_3d/extras/3rd_party/import_sgt.gd

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+# Copyright © 2023-2026 Cory Petkovsek, Roope Palmroos, and Contributors.
+# Import From SimpleGrassTextured
+# 
+# This script demonstrates how to import transforms from SimpleGrassTextured. To use it:
+#
+# 1. Setup the mesh asset you wish to use in the asset dock.
+# 1. Select your Terrain3D node.
+# 1. In the inspector, click Script (very bottom) and Quick Load import_sgt.gd.
+# 1. At the very top, assign your SimpleGrassTextured node.
+# 1. Input the desired mesh asset ID.
+# 1. Click import. The output window and console will report when finished.
+# 1. Clear the script from your Terrain3D node, and save your scene. 
+#
+# The instance transforms are now stored in your region files.
+#
+# Use clear_instances to erase all instances that match the assign_mesh_id.
+#
+# The add_transforms function (called by add_multimesh) applies the height_offset specified in the 
+# Terrain3DMeshAsset. 
+# Once the transforms are imported, you can reassign any mesh you like into this mesh slot.
+
+@tool
+extends Terrain3D
+
+@export var simple_grass_textured: MultiMeshInstance3D
+@export var assign_mesh_id: int
+@export var import: bool = false : set = import_sgt
+@export var clear_instances: bool = false : set = clear_multimeshes
+
+
+func clear_multimeshes(value: bool) -> void:
+	get_instancer().clear_by_mesh(assign_mesh_id)
+
+
+func import_sgt(value: bool) -> void:
+	var sgt_mm: MultiMesh = simple_grass_textured.multimesh
+	var global_xform: Transform3D = simple_grass_textured.global_transform	
+	print("Starting to import %d instances from SimpleGrassTextured using mesh id %d" % [ sgt_mm.instance_count, assign_mesh_id])
+	var time: int = Time.get_ticks_msec()
+	get_instancer().add_multimesh(assign_mesh_id, sgt_mm, simple_grass_textured.global_transform)	
+	print("Import complete in %.2f seconds" % [ float(Time.get_ticks_msec() - time)/1000. ])
+	

addons/terrain_3d/extras/3rd_party/import_sgt.gd.uid

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+uid://bllcuwetve45k

addons/terrain_3d/extras/3rd_party/project_on_terrain3d.gd

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+# Copyright © 2023-2026 Cory Petkovsek, Roope Palmroos, and Contributors.
+# 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 (select, press CTRL+K)
+# 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 : bool = false
+#@export_range(0.0, 90.0, 0.1) var max_slope : float = 90.0
+#@export var enable_texture_filtering : bool = false
+#@export_range(0, 31) var target_texture_id : int = 0
+#@export var not_target_texture : bool = false
+#@export_range(0.0, 1.0, 0.01) var texture_threshold : float = 0.8
+#
+#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 modified version of `Project on Colliders` that queries Terrain3D
+		#for heights without using collision. It constrains placement by slope or texture.
+#
+		#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.")
+		#
+	#p = documentation.add_parameter("Enable Texture Filtering")
+	#p.set_type("bool")
+	#p.set_description(
+		#"If enabled, objects will only be placed based on the ground texture specified.")
+		#
+	#p = documentation.add_parameter("Target Texture ID")
+	#p.set_type("int")
+	#p.set_description(
+		#"The ID of the texture to place objects on (0-31). Objects will only be placed on this texture.")
+		#
+	#p = documentation.add_parameter("Not Target Texture")
+	#p.set_type("bool") 
+	#p.set_description(
+		#"If true, objects will be placed on all textures EXCEPT the target texture.")
+		#
+	#p = documentation.add_parameter("Texture Threshold")
+	#p.set_type("float") 
+	#p.set_description("The blend value required for placement on the texture.")
+#
+#
+#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.data:
+		#warning += """Terrain3DData is not initialized"""
+		#return
+#
+	## Review transforms
+	#var gt: Transform3D = domain.get_global_transform()
+	#var gt_inverse := gt.affine_inverse()
+	#var new_transforms_array: Array[Transform3D] = []
+	#var remapped_max_slope: float = remap(max_slope, 0.0, 90.0, 0.0, 1.0)
+	#for i in transforms.list.size():
+		#var t: Transform3D = transforms.list[i]
+		#
+		#var location: Vector3 = (gt * t).origin
+		#var height: float = _terrain.data.get_height(location)		
+		#if is_nan(height):
+			#continue
+		#
+		#var normal: Vector3 = _terrain.data.get_normal(location)
+		#if not abs(Vector3.UP.dot(normal)) >= (1.0 - remapped_max_slope):
+			#continue
+		#
+		#if enable_texture_filtering:
+			#var texture_info: Vector3 = _terrain.data.get_texture_id(location)
+			#var base_id: int = int(texture_info.x)
+			#var overlay_id: int = int(texture_info.y)
+			#var blend_value: float = texture_info.z
+			## Skip if overlay or blend != target texture, unless inverted
+			#if ((overlay_id != target_texture_id or blend_value < texture_threshold) and \
+				#(base_id != target_texture_id or blend_value >= texture_threshold)) != not_target_texture:
+					#continue
+#
+		#if align_with_collision_normal and not is_nan(normal.x):
+			#t.basis.y = normal
+			#t.basis.x = -t.basis.z.cross(normal)
+			#t.basis = t.basis.orthonormalized()
+#
+		#t.origin.y = height - gt.origin.y
+		#new_transforms_array.push_back(t)
+#
+	#transforms.list.clear()
+	#transforms.list.append_array(new_transforms_array)
+#
+	#if transforms.is_empty():
+		#warning += """All transforms have been removed. Possible reasons include: \n"""
+		#if enable_texture_filtering:
+			#warning += """+ No matching texture found at any position.
+			#+ Texture threshold may be too high.
+			#"""
+		#warning += """+ 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.
+		#"""

addons/terrain_3d/extras/3rd_party/project_on_terrain3d.gd.uid

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+uid://g3opjh3m3iww