Improve GeneratorSimple's terrain shape

Previously, `points` would be reused and (for example)
rotated multiple times, rather than once by the desired
angle, which resulted in nonsensical variant order.

Now, variants with indices 0 to 3 correctly correspond
to rotations of 0, 90, 180 and 270 degrees.

world/block_region.gd

@@ -0,0 +1,45 @@
+class_name BlockRegion
+extends RefCounted
+
+static var LOCAL_CHUNK := BlockRegion.new(Vector2i.ZERO, Vector2i.ONE * (Chunk.SIZE - 1))
+
+var min: Vector2i
+var max: Vector2i
+
+func _init(a: Vector2i, b: Vector2i) -> void:
+	min = a.min(b)
+	max = a.max(b)
+
+func size() -> Vector2i:
+	return max - min + Vector2i.ONE
+
+func contains(pos: Vector2i) -> bool:
+	return (pos.x >= min.x) && (pos.x <= max.x) and (pos.y >= min.y) && (pos.y <= max.y)
+
+
+func offset(value: Vector2i) -> BlockRegion:
+	return BlockRegion.new(min + value, max + value)
+
+func extend(amount: int) -> BlockRegion:
+	var v := Vector2i.ONE * amount
+	return BlockRegion.new(min - v, max + v)
+
+
+func array_index(pos: Vector2i) -> int:
+	assert(contains(pos))
+	var size  := size()
+	var index := (pos.x - min.x) + (pos.y - min.y) * size.x
+	return clampi(index, 0, size.x * size.y)
+
+
+# Custom iterators in GDScript are WEIRD.
+func _iter_init(state: Array) -> bool:
+	state[0] = min
+	return true
+func _iter_next(state: Array) -> bool:
+	var cur: Vector2i = state[0]
+	if   cur.x < max.x: state[0].x += 1; return true
+	elif cur.y < max.y: state[0] = Vector2i(min.x, cur.y + 1); return true
+	else: return false
+func _iter_get(state: Variant) -> Vector2i:
+	return state

world/block_region.gd.uid

@@ -0,0 +1 @@
+uid://w5fuyrkwf40c

world/chunk.gd

@@ -7,6 +7,7 @@ const SIZE := 32 # blocks
 signal clean
 
 var chunk_pos: Vector2i
+var region: BlockRegion
 var dirty := false
 
 var tracked_by: Dictionary[ChunkLoader, Variant] # value is unused
@@ -19,6 +20,11 @@ func get_players_tracking() -> Array[Player]:
 
 func _init(chunk_pos: Vector2i) -> void:
 	self.chunk_pos = chunk_pos
+
+	var min := chunk_pos * Chunk.SIZE
+	var max := (chunk_pos + Vector2i.ONE) * Chunk.SIZE - Vector2i.ONE
+	region = BlockRegion.new(min, max)
+
 	name     = "Chunk %s" % chunk_pos
 	position = (Vector2(chunk_pos) + Vector2.ONE / 2) * (Block.SIZE * SIZE)
 
@@ -76,7 +82,4 @@ static func pos_to_center(chunk_pos: Vector2i) -> Vector2:
 
 ## Creates an integer index from a chunk-local block position that can be used to index into an array.
 static func array_index(local_pos: Vector2i) -> int:
-	assert((local_pos.x >= 0) and (local_pos.x < Chunk.SIZE))
-	assert((local_pos.y >= 0) and (local_pos.y < Chunk.SIZE))
-	# Using `posmod` ensures `local_pos` is valid, and this returns a valid index.
-	return posmod(local_pos.x, Chunk.SIZE) + posmod(local_pos.y, Chunk.SIZE) * Chunk.SIZE
+	return BlockRegion.LOCAL_CHUNK.array_index(local_pos)

world/generation/generator_simple.gd

@@ -4,7 +4,7 @@ extends RefCounted
 const NAME := "simple"
 
 var noise := FastNoiseLite.new()
-var array := PackedFloat32Array()
+var array := PackedByteArray()
 
 var bias_air   :=  0.0 # Above this, always air
 var bias_solid := 64.0 # Below this, always solid
@@ -17,44 +17,224 @@ func _init() -> void:
 	noise.fractal_lacunarity = 2.5
 	noise.fractal_octaves    = 3
 
-	array.resize((Chunk.SIZE + 1) * (Chunk.SIZE + 1))
+	array.resize((Chunk.SIZE + 4) * (Chunk.SIZE + 4))
 
 func generate(world: World, chunk: Chunk) -> void:
+	const THRESHOLD := 0.5
+	var region := chunk.region.extend(2)
+
 	var i := 0
-	for y in Chunk.SIZE + 1:
-		for x in Chunk.SIZE + 1:
-			var local_pos := Vector2i(x, y)
-			var block_pos := (chunk.chunk_pos * Chunk.SIZE) + local_pos
-			var bias := (block_pos.y - bias_air) / (bias_solid - bias_air)
-			array[i] = noise.get_noise_2dv(Vector2(block_pos)) + bias
+	for pos in region:
+		var bias := (pos.y - bias_air) / (bias_solid - bias_air)
+		array[i] = int((noise.get_noise_2dv(Vector2(pos)) + bias) >= THRESHOLD)
 		i += 1
 
 	var matter: Matter.Layer = chunk.get_or_create_layer(Matter)
 	var shapes: Shape.Layer  = chunk.get_or_create_layer(Shape)
-	for x in Chunk.SIZE:
-		for y in Chunk.SIZE:
-			var local_pos := Vector2i(x, y)
+	for pos in BlockRegion.LOCAL_CHUNK:
 		var shape: Shape
-			match _values(local_pos):
-				[  true,  true,  true,  true ]: shape = Shape.FULL
-				[ false,  true,  true,  true ]: shape = Shape.Base.SLOPE.variants[0]
-				[  true, false,  true,  true ]: shape = Shape.Base.SLOPE.variants[2]
-				[  true,  true, false,  true ]: shape = Shape.Base.SLOPE.variants[3]
-				[  true,  true,  true, false ]: shape = Shape.Base.SLOPE.variants[1]
-				[ false, false,  true,  true ]: shape = Shape.Base.HALF.variants[0]
-				[  true, false, false,  true ]: shape = Shape.Base.HALF.variants[2]
-				[  true,  true, false, false ]: shape = Shape.Base.HALF.variants[3]
-				[ false,  true,  true, false ]: shape = Shape.Base.HALF.variants[1]
-			if shape:
-				matter.set_at(local_pos, Matter.PLASTIC)
-				shapes.set_at(local_pos, shape)
-
-func _values(pos: Vector2i) -> Array[bool]:
-	return [
-		_v(pos, 0, 0) >= 0.5,
-		_v(pos, 1, 0) >= 0.5,
-		_v(pos, 1, 1) >= 0.5,
-		_v(pos, 0, 1) >= 0.5,
+
+		var a := array
+		const W := (Chunk.SIZE + 4)
+		i = (pos.x + 2) + (pos.y + 2) * W
+
+		var values: Array[int] = [
+			a[i-2-W*2], a[i-1-W*2], a[i-W*2], a[i+1-W*2], a[i+2-W*2],
+			a[i-2-W  ], a[i-1-W  ], a[i-W  ], a[i+1-W  ], a[i+2-W  ],
+			a[i-2    ], a[i-1    ], a[i    ], a[i+1    ], a[i+2    ],
+			a[i-2+W  ], a[i-1+W  ], a[i+W  ], a[i+1+W  ], a[i+2+W  ],
+			a[i-2+W*2], a[i-1+W*2], a[i+W*2], a[i+1+W*2], a[i+2+W*2],
 		]
-func _v(pos: Vector2i, x: float, y: float) -> float:
-	return array[(pos.x + x) + (pos.y + y) * (Chunk.SIZE + 1)]
+
+		# TODO: Implement custom pattern matching that can handle rotation and mirroring.
+		# var x := -1
+		# var pattern: Array[int] = [
+		# 	x, x, x, x, x,
+		# 	x, x, 0, 0, 0,
+		# 	x, 0, 0, 1, 1,
+		# 	x, 1, 1, 1, x,
+		# 	x, x, x, x, x,
+		# ]
+
+		match values:
+			# HALF_SLOPE (non-mirrored)
+			[
+				_, _, _, _, _,
+				_, _, 0, 0, 0,
+				_, 0, 0, 1, 1,
+				_, 1, 1, 1, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE.variants[0]
+			[
+				_, 0, 1, _, _,
+				_, 0, 1, 1, _,
+				_, 0, 0, 1, _,
+				_, _, 0, 1, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE.variants[1]
+			[
+				_, _, _, _, _,
+				_, 1, 1, 1, _,
+				1, 1, 0, 0, _,
+				0, 0, 0, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE.variants[2]
+			[
+				_, _, _, _, _,
+				_, 1, 0, _, _,
+				_, 1, 0, 0, _,
+				_, 1, 1, 0, _,
+				_, _, 1, 0, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE.variants[3]
+
+			[
+				_, _, _, _, _,
+				_, 0, 0, 0, _,
+				0, 0, 1, 1, _,
+				1, 1, 1, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE_BIG.variants[0]
+			[
+				_, _, _, _, _,
+				_, 0, 1, _, _,
+				_, 0, 1, 1, _,
+				_, 0, 0, 1, _,
+				_, _, 0, 1, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE_BIG.variants[1]
+			[
+				_, _, _, _, _,
+				_, _, 1, 1, 1,
+				_, 1, 1, 0, 0,
+				_, 0, 0, 0, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE_BIG.variants[2]
+			[
+				_, 1, 0, _, _,
+				_, 1, 0, 0, _,
+				_, 1, 1, 0, _,
+				_, _, 1, 0, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE_BIG.variants[3]
+
+			# HALF_SLOPE (mirrored)
+			[
+				_, _, _, _, _,
+				0, 0, 0, _, _,
+				1, 1, 0, 0, _,
+				_, 1, 1, 1, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE.variants[4]
+			[
+				_, _, _, _, _,
+				_, _, 0, 1, _,
+				_, 0, 0, 1, _,
+				_, 0, 1, 1, _,
+				_, 0, 1, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE.variants[5]
+			[
+				_, _, _, _, _,
+				_, 1, 1, 1, _,
+				_, 0, 0, 1, 1,
+				_, _, 0, 0, 0,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE.variants[6]
+			[
+				_, _, 1, 0, _,
+				_, 1, 1, 0, _,
+				_, 1, 0, 0, _,
+				_, 1, 0, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE.variants[7]
+
+			[
+				_, _, _, _, _,
+				_, 0, 0, 0, _,
+				_, 1, 1, 0, 0,
+				_, _, 1, 1, 1,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE_BIG.variants[4]
+			[
+				_, _, 0, 1, _,
+				_, 0, 0, 1, _,
+				_, 0, 1, 1, _,
+				_, 0, 1, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE_BIG.variants[5]
+			[
+				_, _, _, _, _,
+				1, 1, 1, _, _,
+				0, 0, 1, 1, _,
+				_, 0, 0, 0, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE_BIG.variants[6]
+			[
+				_, _, _, _, _,
+				_, _, 1, 0, _,
+				_, 1, 1, 0, _,
+				_, 1, 0, 0, _,
+				_, 1, 0, _, _,
+			]:
+				shape = Shape.Base.HALF_SLOPE_BIG.variants[7]
+
+			# SLOPE
+			[
+				_, _, _, _, _,
+				_, _, 0, _, _,
+				_, 0, 0, 1, _,
+				_, _, 1, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.SLOPE.variants[0]
+			[
+				_, _, _, _, _,
+				_, _, 1, _, _,
+				_, 0, 0, 1, _,
+				_, _, 0, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.SLOPE.variants[1]
+			[
+				_, _, _, _, _,
+				_, _, 1, _, _,
+				_, 1, 0, 0, _,
+				_, _, 0, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.SLOPE.variants[2]
+			[
+				_, _, _, _, _,
+				_, _, 0, _, _,
+				_, 1, 0, 0, _,
+				_, _, 1, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.Base.SLOPE.variants[3]
+
+			# FULL
+			[
+				_, _, _, _, _,
+				_, _, _, _, _,
+				_, _, 1, _, _,
+				_, _, _, _, _,
+				_, _, _, _, _,
+			]:
+				shape = Shape.FULL
+
+		if shape:
+			matter.set_at(pos, Matter.PLASTIC)
+			shapes.set_at(pos, shape)

world/layers/matter.gd

@@ -5,6 +5,7 @@ static var REGISTRY := Registry.new()
 static var NONE    := Matter.new("none")
 static var PLASTIC := Matter.new("plastic")
 
+## Default matter to return when chunk or layer is not found.
 static var DEFAULT := NONE
 
 var id   : int
@@ -41,13 +42,14 @@ class Layer extends MeshInstance2D:
 	@rpc("reliable")
 	func set_id_at(pos: Vector2i, id: int) -> void:
 		var index := Chunk.array_index(pos)
-		if data[index] != id:
+		if data[index] == id: return
+
 		# TODO: Keep track of how many non-air blocks are present, to allow for cleaning empty chunks.
 		data[index] = id
 		chunk.dirty = true
 
-			# Send change to every player tracking this chunk.
 		if multiplayer.is_server():
+			# Send change to every player tracking this chunk.
 			for player in chunk.get_players_tracking():
 				if player.network.is_local: continue # skip server player
 				set_id_at.rpc_id(player.network.peer_id, pos, id)
@@ -66,9 +68,7 @@ class Layer extends MeshInstance2D:
 
 		var shapes: Shape.Layer = chunk.get_layer_or_null(Shape)
 		if shapes: # Should exist, but let's sanity check.
-			for x in Chunk.SIZE:
-				for y in Chunk.SIZE:
-					var pos    := Vector2i(x, y)
+			for pos in BlockRegion.LOCAL_CHUNK:
 				var offset := (Vector2.ONE / 2) + Vector2(pos)
 
 				# TODO: Support different matter.

world/layers/shape.gd

@@ -9,6 +9,7 @@ static func lookup(id: int) -> Shape:
 static var EMPTY : Shape
 static var FULL  : Shape
 
+## Default shape to return when chunk or layer is not found.
 static var DEFAULT : Shape
 
 var id     : int
@@ -34,12 +35,14 @@ func _init(base: Base, mirror: bool, angle: int, shape: Shape2D, points: PackedV
 		uvs.append((Vector2.ONE / 2) + point)
 
 
+## Represents a base shape, before it has been rotated and mirrored
+## (if applicable) to create a number of variants based on that shape.
 class Base:
 	static var EMPTY          := Base.new("empty")
 	static var FULL           := Base.new("full"          , _rect())
 	static var HALF           := Base.new("half"          , [ 0,1, 2,1, 2,2, 0,2 ], true)
 	static var SLOPE          := Base.new("slope"         , [ 0,1, 1,0, 1,1      ], true)
-	static var HALF_SLOPE     := Base.new("half_slope"    , [ 0,2, 1,0, 2,2      ], true, true)
+	static var HALF_SLOPE     := Base.new("half_slope"    , [ 0,2, 2,1, 2,2      ], true, true)
 	static var HALF_SLOPE_BIG := Base.new("half_slope_big", [ 0,1, 2,0, 2,2, 0,2 ], true, true)
 
 	static func _static_init() -> void:
@@ -60,28 +63,25 @@ class Base:
 				shape = _rotate(shape) # rotate by 90 degrees (swap x and y components)
 				variants.append(Shape.new(self, false, 0, shape, _points(shape)))
 		elif shape is Array:
-			# Convert points (pairs of ints) in array to convex shape.
+			# Convert points (pairs of `int`s) in `Array` to convex shape.
 			var factor := float(shape.max())
-			var points := PackedVector2Array()
+			var points_orig := PackedVector2Array() # untransformed points
 			for i in range(0, shape.size(), 2):
 				var point := Vector2(shape[i] / factor, shape[i + 1] / factor)
-				points.append(point - (Vector2.ONE / 2)) # ensure shape is centered
+				points_orig.append(point - (Vector2.ONE / 2)) # ensure shape is centered
 
 			# Add variations of the shape (rotated, mirrored), including the standard shape.
 			for mirror in [ false, true ] if mirrored else [ false ]:
-				if mirror:
-					# Mirror (flip) points along the X axis.
-					points = points.duplicate()
-					for i in points.size():
-						points[i] = points[i] * Transform2D.FLIP_X
-
 				for angle in [ 0, 90, 180, 270 ] if rotated else [ 0 ]:
-					if angle != 0:
-						# Rotate points around the center.
+					var points := points_orig.duplicate() # transformed points
+					# Technically we could skip `duplicate()` if not mirrored and not rotated, but eh.
+
+					if mirror: # Mirror (flip) points along the X axis.
+						for i in points.size(): points[i] *= Transform2D.FLIP_X
+
+					if angle != 0: # Rotate points around the center.
 						var transform := Transform2D(deg_to_rad(angle), Vector2.ZERO)
-						points = points.duplicate()
-						for i in points.size():
-							points[i] = points[i] * transform
+						for i in points.size(): points[i] *= transform
 
 					var shape_points: PackedVector2Array
 					for point in points: shape_points.append(point * Block.SIZE)
@@ -130,13 +130,14 @@ class Layer extends StaticBody2D:
 	@rpc("reliable")
 	func set_id_at(pos: Vector2i, id: int) -> void:
 		var index := Chunk.array_index(pos)
-		if data[index] != id:
+		if data[index] == id: return
+
 		# TODO: Keep track of how many non-air blocks are present, to allow for cleaning empty chunks.
 		data[index] = id
 		chunk.dirty = true
 
-			# Send change to every player tracking this chunk.
 		if multiplayer.is_server():
+			# Send change to every player tracking this chunk.
 			for player in chunk.get_players_tracking():
 				if player.network.is_local: continue # skip server player
 				set_id_at.rpc_id(player.network.peer_id, pos, id)
@@ -155,9 +156,7 @@ class Layer extends StaticBody2D:
 			if child is CollisionShape2D:
 				child.queue_free()
 
-		for x in Chunk.SIZE:
-			for y in Chunk.SIZE:
-				var pos   := Vector2i(x, y)
+		for pos in BlockRegion.LOCAL_CHUNK:
 			var shape := get_at(pos)
 			if shape.shape == null: continue