Fix leaky abstractions in EditableTerrain

editor/editable_terrain.gd

@@ -1,15 +1,37 @@
 class_name EditableTerrain extends Node
 
+const _DEFAULT_COLOR := Color(0.0, 0.0, 0.0, 0.5)
+
+##
+## Blank sample value.
+##
+const BLANK := Color(0.0, 0.0, 0.0, 0.0)
+
 var _image := Image.create(1, 1, false, Image.FORMAT_RGBAF)
 
 ##
+## Terrain texture channel mixing values.
 ##
+## Affects the color that terrain is mixed into during editing operations like [method paint].
 ##
 @export
 var channels := Vector3.ZERO
 
 ##
+## Tracked [TerrainInstance3D] to echo all terrain editing changes to.
 ##
+var instance: TerrainInstance3D = null:
+	get:
+		return instance
+
+	set(value):
+		if (value != null) and (value != instance):
+			value.terrain_map = ImageTexture.create_from_image(_image)
+
+		instance = value
+
+##
+## Width and height of the editable terrain in units.
 ##
 @export
 var size := Vector2i.ZERO:
@@ -18,18 +40,23 @@ var size := Vector2i.ZERO:
 
 	set(value):
 		_image.resize(value.x, value.y)
-		_image.fill(Color(0.0, 0.0, 0.0, 0.5))
+
+		if instance != null:
+			instance.size = value
+			instance.terrain_map = ImageTexture.create_from_image(_image)
 
 		size = value
 
-##
+func _init() -> void:
-##
+	_image.fill(_DEFAULT_COLOR)
-##
-func get_image() -> void:
-	return _image
 
 ##
+## Mixes the texture [member channels] and raises the terrain by [code]elevation_level[/code] in a
+## brush pattern masked by [code]brush_mask[/code] to the worldspace [code]point[/code] with
+## [code]brush_intensity[/code] as the intensity of the applied effects for a single paint.
 ##
+## For continuous painting, a delta value may be supplied to [code]brush_intensity[/code] to avoid
+## issues with variable-rate paint updates.
 ##
 func paint(point: Vector2i, elevation_level: float,
 	brush_mask: Image, brush_scale: float, brush_intensity: float) -> void:
@@ -37,10 +64,9 @@ func paint(point: Vector2i, elevation_level: float,
 	# Convert worldspace point to image-space coordinates for brush and calculate drawable area.
 	var brush_mask_size := brush_mask.get_size()
 	var brush_size := brush_mask_size * brush_scale
-	var image_size := _image.get_size()
 
-	var draw_area := Rect2i(Vector2i.ZERO, image_size).intersection(
+	var draw_area := Rect2i(Vector2i.ZERO, size).intersection(
-		Rect2i((point - Vector2i(brush_size * 0.5)) + Vector2i(image_size * 0.5), brush_size))
+		Rect2i((point - Vector2i(brush_size * 0.5)) + Vector2i(size * 0.5), brush_size))
 
 	if draw_area.has_area():
 		var scaled_brush_mask_size := brush_mask_size / draw_area.size
@@ -65,8 +91,30 @@ func paint(point: Vector2i, elevation_level: float,
 							lerpf(pixel.b, channels.z, mask_intensity),
 								lerpf(pixel.a, pixel.a + (elevation_level * mask), brush_intensity)))
 
+			instance.terrain_map.update(_image)
+
 ##
+## Samples the color value in the editable terrain at the worldspace [code]point[/code], returning
+## its respective [Color] value.
 ##
+## For sample coordinates outside of the terrain map worldspace, [code]BLANK[/code] is returned
+## instead.
+##
+func sample(point: Vector2i) -> Color:
+	var image_point := point + Vector2i(size * 0.5)
+
+	if Rect2i(Vector2i.ZERO, size).has_point(image_point):
+		return _image.get_pixelv(image_point)
+
+	return BLANK
+
+##
+## Mixes the texture [member channels] and smooths the terrain to [code]smoothing_level[/code] in a
+## brush pattern masked by [code]brush_mask[/code] to the worldspace [code]point[/code] with
+## [code]brush_intensity[/code] as the intensity of the applied effects for a single paint.
+##
+## For continuous smoothing, a delta value may be supplied to [code]brush_intensity[/code] to avoid
+## issues with variable-rate smooth updates.
 ##
 func smooth(point: Vector2i, smoothing_level: float,
 	brush_mask: Image, brush_scale: float, brush_intensity: float) -> void:
@@ -98,3 +146,5 @@ func smooth(point: Vector2i, smoothing_level: float,
 						lerpf(pixel.g, channels.y, mask_intensity), 
 							lerpf(pixel.b, channels.z, mask_intensity),
 								lerpf(pixel.a, smoothing_level, mask_intensity)))
+
+		instance.terrain_map.update(_image)