GunkBody takes an optional initial gunk mask

assets/debug_mask.png.import

@@ -3,20 +3,19 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://8cm835h4gxwe"
-path.s3tc="res://.godot/imported/debug_mask.png-fd2bc783338ed9439fe81a4eef9d86da.s3tc.ctex"
+path="res://.godot/imported/debug_mask.png-fd2bc783338ed9439fe81a4eef9d86da.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 
 [deps]
 
 source_file="res://assets/debug_mask.png"
-dest_files=["res://.godot/imported/debug_mask.png-fd2bc783338ed9439fe81a4eef9d86da.s3tc.ctex"]
+dest_files=["res://.godot/imported/debug_mask.png-fd2bc783338ed9439fe81a4eef9d86da.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/hdr_compression=1

levels/sandbox/sandbox.tscn

@@ -1,7 +1,8 @@
-[gd_scene load_steps=46 format=4 uid="uid://16ds4fvv72xk"]
+[gd_scene load_steps=47 format=4 uid="uid://16ds4fvv72xk"]
 
 [ext_resource type="PackedScene" uid="uid://c2omlx4ptrc01" path="res://src/world/gunk_body/gunk_body.tscn" id="1_a67lu"]
 [ext_resource type="PackedScene" uid="uid://bwe2jdmvinhqd" path="res://src/player/player.tscn" id="1_h436a"]
+[ext_resource type="Texture2D" uid="uid://8cm835h4gxwe" path="res://assets/debug_mask.png" id="2_2roq2"]
 [ext_resource type="Shader" uid="uid://ckxc0ngd37rtk" path="res://src/shaders/gunk.gdshader" id="5_rdjtm"]
 [ext_resource type="Texture2D" uid="uid://bniqwnr66mvwa" path="res://assets/level/hallway/hallway_1_C.png" id="6_hrvvi"]
 [ext_resource type="FastNoiseLite" uid="uid://cnlvdtx68giv6" path="res://assets/materials/gunk_noise.tres" id="6_l64ek"]
@@ -397,6 +398,7 @@ shape = SubResource("WorldBoundaryShape3D_c8g65")
 [node name="Icosahedron" parent="Geometry" node_paths=PackedStringArray("mesh_instance") instance=ExtResource("1_a67lu")]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3.35498, 1.13294, -2.81423)
 mesh_instance = NodePath("MeshInstance3D")
+initial_mask = ExtResource("2_2roq2")
 
 [node name="MeshInstance3D" type="MeshInstance3D" parent="Geometry/Icosahedron"]
 mesh = SubResource("ArrayMesh_2roq2")

src/world/gunk_body/draw_controller.gd

@@ -6,10 +6,16 @@ signal painted
 var _draw_queue: Array[Callable] = []
 
 var _dirty := false
+var _clear := true
+var _show_texture := true
+
+@onready var mask_clear: ColorRect = %MaskClear
+@onready var mask_texture: TextureRect = %MaskTexture
 
 
 func clear(color: Color) -> void:
-	queue_draw(func() -> void: draw_rect(Rect2(0, 0, size.x, size.y), color, true))
+	mask_clear.color = color
+	_clear = true
 
 
 func queue_draw(op: Callable) -> void:
@@ -28,3 +34,9 @@ func _process(_delta: float) -> void:
 		queue_redraw()
 		_dirty = false
 		painted.emit()
+
+	# show clear rect for one frame
+	mask_clear.visible = _clear
+	_clear = false
+	mask_texture.visible = _show_texture
+	_show_texture = false

src/world/gunk_body/gunk_body.gd

@@ -13,6 +13,7 @@ const CLEAR_TOTAL_EPSILON := 1
 
 @export var mask_dim := 256
 @export var mesh_instance: MeshInstance3D
+@export var initial_mask: Texture
 
 var meshtool := MeshDataTool.new()
 
@@ -34,8 +35,7 @@ var _exit_thread := false
 
 @onready var mask_viewport: SubViewport = %MaskViewport
 @onready var mask_control: DrawController = %MaskControl
-
-@onready var debug_draw: DebugDraw = $DebugDraw
+@onready var mask_texture: TextureRect = %MaskTexture
 
 
 func _ready() -> void:
@@ -51,6 +51,9 @@ func _ready() -> void:
 	gunk_mat.set_shader_parameter("gunk_mask", mask_viewport.get_texture())
 	meshtool.create_from_surface(mesh_instance.mesh as ArrayMesh, 0)
 
+	if initial_mask:
+		mask_texture.texture = initial_mask
+
 	_thread = Thread.new()
 	_thread.start(_async_compute_clear_total)
 
@@ -180,8 +183,6 @@ func paint_dot(point: Vector3, normal: Vector3, radius: float) -> void:
 
 ## Paint a continuous line on the gunk mask if called on successive frames.
 func paint_continuous(point: Vector3, normal: Vector3, width: float) -> void:
-	debug_draw.draw_vector(normal, point)
-
 	var px := _get_px(point, normal)
 	if _polyline_buffer and px.distance_to(_polyline_buffer[0]) <= CONTINUITY_LIMIT:
 		_polyline_buffer.push_front(px)

src/world/gunk_body/gunk_body.tscn

@@ -1,8 +1,7 @@
-[gd_scene load_steps=4 format=3 uid="uid://c2omlx4ptrc01"]
+[gd_scene load_steps=3 format=3 uid="uid://c2omlx4ptrc01"]
 
 [ext_resource type="Script" uid="uid://hbl5u20wlwr5" path="res://src/world/gunk_body/gunk_body.gd" id="1_qqbpr"]
 [ext_resource type="Script" uid="uid://bom5qysgfvap1" path="res://src/world/gunk_body/draw_controller.gd" id="2_kkcjw"]
-[ext_resource type="Script" uid="uid://ba7480ara8eo" path="res://levels/sandbox/debug_draw.gd" id="3_m8wx4"]
 
 [node name="GunkBody" type="StaticBody3D"]
 script = ExtResource("1_qqbpr")
@@ -14,6 +13,23 @@ size = Vector2i(1024, 1024)
 render_target_clear_mode = 1
 render_target_update_mode = 4
 
+[node name="MaskClear" type="ColorRect" parent="MaskViewport"]
+unique_name_in_owner = true
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+color = Color(0, 0, 0, 1)
+
+[node name="MaskTexture" type="TextureRect" parent="MaskViewport"]
+unique_name_in_owner = true
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+
 [node name="MaskControl" type="Control" parent="MaskViewport"]
 unique_name_in_owner = true
 layout_mode = 3
@@ -24,11 +40,4 @@ grow_horizontal = 2
 grow_vertical = 2
 script = ExtResource("2_kkcjw")
 
-[node name="DebugDraw" type="Control" parent="."]
-layout_mode = 3
-anchors_preset = 0
-offset_right = 40.0
-offset_bottom = 40.0
-script = ExtResource("3_m8wx4")
-
 [connection signal="painted" from="MaskViewport/MaskControl" to="." method="_on_mask_painted"]