straywild/world/generation/terrain_chunk_generator.gd

396 lines
11 KiB
GDScript

class_name TerrainChunkGenerator
extends Node3D
signal generation_completed(summary: Dictionary)
const EDGE_PROFILE_QUANTIZATION := 0.001
@export var catalog: TerrainChunkCatalog
@export var grid_size := Vector2i(5, 5)
@export var generation_seed := 13001
@export var generate_on_ready := true
@export var build_collision := true
@export var show_chunk_labels := false
@export var force_center_chunk_id: StringName = &"chunk_0000"
@export var required_chunk_ids := PackedStringArray()
@export_range(1.0, 100.0, 1.0) var required_chunk_weight_multiplier := 64.0
@export_range(0.001, 0.1, 0.001) var edge_match_tolerance := 0.01
@export_range(1, 100000, 1) var maximum_backtracks := 20000
var _variants: Array[TerrainChunkVariant] = []
var _placements: Array[TerrainChunkVariant] = []
var _random := RandomNumberGenerator.new()
var _generated_chunks: Node3D
var _backtrack_count := 0
func _ready() -> void:
if generate_on_ready:
call_deferred(&"generate")
func generate() -> bool:
_clear_generated_chunks()
if not _prepare_catalog():
return false
_random.seed = generation_seed
_backtrack_count = 0
_placements.clear()
_placements.resize(grid_size.x * grid_size.y)
if not _solve_cell(0):
push_error(
"Terrain generation could not solve a %dx%d grid with seed %d."
% [grid_size.x, grid_size.y, generation_seed]
)
return false
_instantiate_solution()
var summary := _build_summary()
generation_completed.emit(summary)
return true
func _prepare_catalog() -> bool:
if catalog == null:
push_error("TerrainChunkGenerator requires a catalog.")
return false
if grid_size.x <= 0 or grid_size.y <= 0:
push_error("TerrainChunkGenerator grid dimensions must be positive.")
return false
var catalog_errors := catalog.validation_errors()
if not catalog_errors.is_empty():
push_error("Terrain chunk catalog is invalid:\n" + "\n".join(catalog_errors))
return false
_variants.clear()
for definition: TerrainChunkDefinition in catalog.definitions:
var analyzed := TerrainChunkAnalyzer.create_variants(
definition,
catalog.chunk_size,
)
var seen_signatures: Dictionary[String, bool] = {}
for variant: TerrainChunkVariant in analyzed:
var signature := variant.topology_signature(
EDGE_PROFILE_QUANTIZATION
)
if seen_signatures.has(signature):
continue
seen_signatures[signature] = true
_variants.append(variant)
if _variants.is_empty():
push_error("Terrain chunk catalog produced no usable variants.")
return false
return true
func _solve_cell(index: int) -> bool:
if index >= _placements.size():
return _required_chunks_are_present()
if _backtrack_count >= maximum_backtracks:
return false
var candidates := _compatible_candidates(index)
for candidate: TerrainChunkVariant in _weighted_candidate_order(candidates):
_placements[index] = candidate
if _solve_cell(index + 1):
return true
_placements[index] = null
_backtrack_count += 1
if _backtrack_count >= maximum_backtracks:
break
return false
func _compatible_candidates(index: int) -> Array[TerrainChunkVariant]:
var result: Array[TerrainChunkVariant] = []
var coordinate := Vector2i(index % grid_size.x, index / grid_size.x)
var center := Vector2i(grid_size.x / 2, grid_size.y / 2)
for candidate: TerrainChunkVariant in _variants:
if not _definition_has_capacity(candidate.definition):
continue
if (
coordinate == center
and force_center_chunk_id != &""
and candidate.definition.stable_id != force_center_chunk_id
):
continue
if coordinate.x > 0:
var west_neighbor := _placements[index - 1]
if (
west_neighbor != null
and not _edges_are_compatible(
candidate,
TerrainChunkTopology.Edge.WEST,
west_neighbor,
TerrainChunkTopology.Edge.EAST,
)
):
continue
if coordinate.y > 0:
var north_neighbor := _placements[index - grid_size.x]
if (
north_neighbor != null
and not _edges_are_compatible(
candidate,
TerrainChunkTopology.Edge.NORTH,
north_neighbor,
TerrainChunkTopology.Edge.SOUTH,
)
):
continue
result.append(candidate)
return result
func _definition_has_capacity(definition: TerrainChunkDefinition) -> bool:
if definition.maximum_placements < 0:
return true
var count := 0
for placement: TerrainChunkVariant in _placements:
if placement != null and placement.definition == definition:
count += 1
return count < definition.maximum_placements
func _edges_are_compatible(
first: TerrainChunkVariant,
first_edge: TerrainChunkTopology.Edge,
second: TerrainChunkVariant,
second_edge: TerrainChunkTopology.Edge,
) -> bool:
if not first.profile(first_edge).matches(
second.profile(second_edge),
edge_match_tolerance,
):
return false
var first_inlet := _variant_edge_has_connector(
first,
first.definition.water_inlet_edges,
first_edge,
)
var first_outlet := _variant_edge_has_connector(
first,
first.definition.water_outlet_edges,
first_edge,
)
var second_inlet := _variant_edge_has_connector(
second,
second.definition.water_inlet_edges,
second_edge,
)
var second_outlet := _variant_edge_has_connector(
second,
second.definition.water_outlet_edges,
second_edge,
)
var first_has_water := first_inlet or first_outlet
var second_has_water := second_inlet or second_outlet
if not first_has_water and not second_has_water:
return true
return (
(first_outlet and second_inlet)
or (first_inlet and second_outlet)
)
func _variant_edge_has_connector(
variant: TerrainChunkVariant,
source_mask: int,
edge: TerrainChunkTopology.Edge,
) -> bool:
return (variant.rotated_edge_mask(source_mask) & (1 << int(edge))) != 0
func _required_chunks_are_present() -> bool:
if required_chunk_ids.is_empty():
return true
var found: Dictionary[StringName, bool] = {}
for placement: TerrainChunkVariant in _placements:
if placement != null:
found[placement.definition.stable_id] = true
for required_id: String in required_chunk_ids:
if not found.has(StringName(required_id)):
return false
return true
func _weighted_candidate_order(
candidates: Array[TerrainChunkVariant],
) -> Array[TerrainChunkVariant]:
var scored: Array[Dictionary] = []
for candidate: TerrainChunkVariant in candidates:
var weight := maxf(candidate.definition.selection_weight, 0.01)
if _required_chunk_is_missing(candidate.definition.stable_id):
weight *= required_chunk_weight_multiplier
var sample := maxf(_random.randf(), 0.000001)
scored.append(
{
"variant": candidate,
"score": pow(sample, 1.0 / weight),
}
)
scored.sort_custom(_higher_candidate_score)
var result: Array[TerrainChunkVariant] = []
for entry: Dictionary in scored:
result.append(entry["variant"] as TerrainChunkVariant)
return result
func _required_chunk_is_missing(stable_id: StringName) -> bool:
if not required_chunk_ids.has(String(stable_id)):
return false
for placement: TerrainChunkVariant in _placements:
if (
placement != null
and placement.definition.stable_id == stable_id
):
return false
return true
func _instantiate_solution() -> void:
_generated_chunks = Node3D.new()
_generated_chunks.name = "GeneratedChunks"
add_child(_generated_chunks)
var half_grid := Vector2(
float(grid_size.x - 1) * 0.5,
float(grid_size.y - 1) * 0.5,
)
for index: int in _placements.size():
var variant := _placements[index]
if variant == null:
continue
var coordinate := Vector2i(index % grid_size.x, index / grid_size.x)
var chunk_root := variant.definition.packed_scene.instantiate() as Node3D
if chunk_root == null:
push_error("%s does not instantiate as Node3D." % variant.stable_key())
continue
chunk_root.name = "%s_%d_%d" % [
variant.stable_key().replace("@", "r"),
coordinate.x,
coordinate.y,
]
chunk_root.position = Vector3(
(float(coordinate.x) - half_grid.x) * catalog.chunk_size,
0.0,
(float(coordinate.y) - half_grid.y) * catalog.chunk_size,
)
chunk_root.rotation.y = variant.rotation_radians()
_generated_chunks.add_child(chunk_root)
if build_collision:
_add_collision(chunk_root, variant.definition)
if show_chunk_labels:
_add_chunk_label(chunk_root, variant)
func _add_collision(
chunk_root: Node3D,
definition: TerrainChunkDefinition,
) -> void:
var primary_mesh := TerrainChunkAnalyzer.find_primary_mesh(
chunk_root,
definition.primary_mesh_name,
)
if primary_mesh == null or primary_mesh.mesh == null:
return
var terrain_shape := primary_mesh.mesh.create_trimesh_shape()
if terrain_shape == null or terrain_shape.get_faces().is_empty():
push_warning("%s produced no terrain collision." % definition.stable_id)
return
var collision_body := StaticBody3D.new()
collision_body.name = "TerrainCollision"
collision_body.collision_layer = 1
collision_body.collision_mask = 0
primary_mesh.add_child(collision_body)
var collision_shape := CollisionShape3D.new()
collision_shape.name = "TerrainShape"
collision_shape.shape = terrain_shape
collision_body.add_child(collision_shape)
func _add_chunk_label(
chunk_root: Node3D,
variant: TerrainChunkVariant,
) -> void:
var label := Label3D.new()
label.name = "ChunkLabel"
label.text = "%s r%d" % [
variant.definition.stable_id,
variant.quarter_turns,
]
label.position = Vector3(0.0, 1.25, 0.0)
label.font_size = 24
label.billboard = BaseMaterial3D.BILLBOARD_ENABLED
label.no_depth_test = true
chunk_root.add_child(label)
func _clear_generated_chunks() -> void:
if is_instance_valid(_generated_chunks):
remove_child(_generated_chunks)
_generated_chunks.free()
_generated_chunks = null
func _build_summary() -> Dictionary:
var counts: Dictionary[StringName, int] = {}
for variant: TerrainChunkVariant in _placements:
if variant == null:
continue
var stable_id := variant.definition.stable_id
counts[stable_id] = counts.get(stable_id, 0) + 1
return {
"seed": generation_seed,
"grid_size": grid_size,
"chunk_count": _placements.size(),
"variant_count": _variants.size(),
"backtracks": _backtrack_count,
"counts": counts,
"placements": placement_keys(),
}
func placement_keys() -> PackedStringArray:
var result := PackedStringArray()
for variant: TerrainChunkVariant in _placements:
result.append(variant.stable_key() if variant != null else "empty")
return result
func placement_records() -> Array[Dictionary]:
var result: Array[Dictionary] = []
for index: int in _placements.size():
var variant: TerrainChunkVariant = _placements[index]
if variant == null:
continue
var coordinate := Vector2i(index % grid_size.x, index / grid_size.x)
result.append({
"coordinate": coordinate,
"position": chunk_position(coordinate),
"rotation_quarters": variant.quarter_turns,
"stable_id": variant.definition.stable_id,
"tags": variant.definition.tags,
"water_surface_size": variant.definition.water_surface_size,
"water_surface_offset": variant.definition.water_surface_offset,
})
return result
func chunk_position(coordinate: Vector2i) -> Vector3:
if catalog == null:
return Vector3.ZERO
var half_grid := Vector2(
float(grid_size.x - 1) * 0.5,
float(grid_size.y - 1) * 0.5,
)
return Vector3(
(float(coordinate.x) - half_grid.x) * catalog.chunk_size,
0.0,
(float(coordinate.y) - half_grid.y) * catalog.chunk_size,
)
func get_generated_chunks_root() -> Node3D:
return _generated_chunks
static func _higher_candidate_score(a: Dictionary, b: Dictionary) -> bool:
return float(a["score"]) > float(b["score"])