Defer initial processing of gunk clear total until both the clear frame and initial mask have been applied

src/world/gunk_body/draw_controller.gd

@@ -1,8 +1,5 @@
 class_name DrawController extends Control
 
-## Emitted the frame after at least one paint operation was done.
-signal painted
-
 var _draw_queue: Array[Callable] = []
 
 var _dirty := false
@@ -33,10 +30,13 @@ func _process(_delta: float) -> void:
 	if _dirty:
 		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
+
+
+func _set_dirty() -> void:
+	_dirty = true

src/world/gunk_body/gunk_body.gd

@@ -27,7 +27,7 @@ var _multiline_buffer := PackedVector2Array()
 var _multiline_width := 1.0
 
 var _clear_total := 0.0
-var _prev_clear_total := 0.0
+var _prev_clear_total := -1.0
 
 # _clear_total is async computed in separate thread
 var _mask_tx: Texture2D
@@ -83,6 +83,12 @@ func _trigger_recompute_deferred() -> void:
 
 
 func _async_compute_clear_total() -> void:
+	# Ignore first two calls (initial mask clear & texture)
+	# NOTE: this technically could put us in a glitched state if that mask clear & texture don't happen
+	# and the thread wouldn't be able to hit the exit condition.
+	# If the application hangs in a weird way immediately after loading a scene, maybe this is why!
+	_semaphore.wait()
+	_semaphore.wait()
 	while true:
 		_semaphore.wait()
 
@@ -184,7 +190,6 @@ func _get_uv(point: Vector3, normal: Vector3) -> Vector2:
 ## Returns Vector2.INF if the given point+normal does not lie on this mesh within tolerance.
 func _get_px(point: Vector3, normal: Vector3) -> Vector2:
 	debug_draw.draw_vector(normal, point)
-	#print_debug("POINT: ", point, "; NORMAL: ", normal)
 
 	return _get_uv(point * global_transform, normal * global_basis) * mask_control.size
 
@@ -241,6 +246,9 @@ func _process(_delta: float) -> void:
 	_mutex.unlock()
 	var delta := new_total - _prev_clear_total
 	if abs(delta) > CLEAR_TOTAL_EPSILON:
+		# Do not fire signal on first compute after initialization
+		# This prevents the player from collecting the grunk from the initial mask.
+		if _prev_clear_total >= 0:
 			clear_total_updated.emit(new_total)
 			# XXX due to fp error, this will drift from the "true count" over time
 			# but it probably won't matter :shrug:
@@ -265,4 +273,4 @@ func _process(_delta: float) -> void:
 
 func _on_mask_painted() -> void:
 	# XXX any problem with posting each frame?
-	call_deferred("_trigger_recompute_deferred")
+	_trigger_recompute_deferred.call_deferred()

src/world/gunk_body/gunk_body.tscn

@@ -56,4 +56,6 @@ grow_vertical = 2
 mouse_filter = 2
 script = ExtResource("3_m8wx4")
 
-[connection signal="painted" from="MaskViewport/MaskControl" to="." method="_on_mask_painted"]
+[connection signal="visibility_changed" from="MaskViewport/MaskClear" to="MaskViewport/MaskControl" method="_set_dirty"]
+[connection signal="visibility_changed" from="MaskViewport/MaskTexture" to="MaskViewport/MaskControl" method="_set_dirty"]
+[connection signal="draw" from="MaskViewport/MaskControl" to="." method="_on_mask_painted"]