Godot-RTS-Template/dev/debug_tools.gd

extends Control
## A utility node for drawing 3D debug visuals (lines, rays, cubes) in screen space.
@export var MouseOverlay: Node
@onready var Cam = get_viewport().get_camera_3d()


# Called when the node enters the scene tree for the first time.
func _ready() -> void:
	if !OS.is_debug_build():
		self.queue_free()
		return

	# Ensure the node processes and draws even when the game is paused.
	process_mode = Node.PROCESS_MODE_ALWAYS
	# Ensure the node is visible and set to draw in screen space.
	set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)


## A class representing a single debug line with start/end points, color, and duration.
class Line:
	var Start:Vector3
	var End:Vector3
	var LineColor:Color
	var time:float


## Constructor for DebugLine. [br]
## [param _start] Starting point in 3D space.[br]
## [param _end] Ending point in 3D space.[br]
## [param _color] Color of the line.[br]
## [param _time] Duration the line persists (seconds).
	func _init(_Start:Vector3, _End:Vector3, _LineColor:Color, _time:float):
		self.Start = _Start
		self.End = _End
		self.LineColor = _LineColor
		self.time = _time

## Array storing all active debug lines.
var Lines = []
## Flag to track if a line was removed, triggering a redraw.
var RemovedLine = false


func _process(delta):
	for i in range(len(Lines)):
		Lines[i].time -= delta
	# Trigger a redraw if lines exist or a line was removed.
	if (len(Lines) > 0 || RemovedLine):
		queue_redraw() #Calls _draw
		RemovedLine = false


func _draw():
	# Exit early if no lines to draw or camera is not available.
	if Lines.is_empty() or not Cam:
		return
	for i in range(len(Lines)):
		if Lines[i].Start.length() == 0:return
		var ScreenPointStart = Cam.unproject_position(Lines[i].Start)
		var ScreenPointEnd = Cam.unproject_position(Lines[i].End)

		#Dont draw line if either start or end is considered behind the camera
		#this causes the line to not be drawn sometimes but avoids a bug where the
		#line is drawn incorrectly
		if (Cam.is_position_behind(Lines[i].Start) ||
			Cam.is_position_behind(Lines[i].End)):
			continue

		draw_line(ScreenPointStart, ScreenPointEnd, Lines[i].LineColor)

	#Remove lines that have timed out
	var i = Lines.size() - 1
	while (i >= 0):
		if (Lines[i].time < 0.0):
			Lines.remove_at(i)
			RemovedLine = true

		i -= 1


## Draws a line between two 3D points. [br]
## [param start] Starting point in 3D space.[br]
## [param end] Ending point in 3D space.[br]
## [param time] Duration the line persists (seconds, default: 0.0 for one frame).[br]
## [param color] Color of the line (default: red, fully opaque).
func DrawLine(Start, End, time := 0.0, LineColor := Color(1.0, 0.0, 0.0, 1.0)):
	Lines.append(Line.new(Start, End, LineColor, time))


## Draws a ray from a starting point in a given direction.[br]
## [param start] Starting point in 3D space.[br]
## [param ray] Direction and magnitude of the ray (Vector3).[br]
## [param time] Duration the ray persists (seconds, default: 0.0 for one frame).[br]
## [param color] Color of the ray (default: red, fully opaque).
func DrawRay(Start, Ray, time := 0.0, LineColor := Color(1.0, 0.0, 0.0, 1.0)):
	Lines.append(Line.new(Start, Start + Ray, LineColor, time))


## Draws a wireframe cube in 3D space.[br]
## [param center] Center point of the cube in 3D space.[br]
## [param half_extents] Half the width of the cube (default: 0.1).[br]
## [param time] Duration the cube persists (seconds, default: 0.0 for one frame).[br]
## [param color] Color of the cube's edges (default: red, fully opaque).
func DrawCube(Center, HalfExtents := 0.1, time := 0.0, LineColor := Color(1.0, 0.0, 0.0, 1.0)):
	#Start at the 'top left'
	var LinePointStart = Center
	LinePointStart.x -= HalfExtents
	LinePointStart.y += HalfExtents
	LinePointStart.z -= HalfExtents

	# Draw top square (four edges).
	var LinePointEnd = LinePointStart + Vector3(0, 0, HalfExtents * 2.0)
	DrawLine(LinePointStart, LinePointEnd, time, LineColor);
	LinePointStart = LinePointEnd
	LinePointEnd = LinePointStart + Vector3(HalfExtents * 2.0, 0, 0)
	DrawLine(LinePointStart, LinePointEnd, time, LineColor);
	LinePointStart = LinePointEnd
	LinePointEnd = LinePointStart + Vector3(0, 0, -HalfExtents * 2.0)
	DrawLine(LinePointStart, LinePointEnd, time, LineColor);
	LinePointStart = LinePointEnd
	LinePointEnd = LinePointStart + Vector3(-HalfExtents * 2.0, 0, 0)
	DrawLine(LinePointStart, LinePointEnd, time, LineColor);

	# Draw bottom square (four edges).
	LinePointStart = LinePointEnd + Vector3(0, -HalfExtents * 2.0, 0)
	LinePointEnd = LinePointStart + Vector3(0, 0, HalfExtents * 2.0)
	DrawLine(LinePointStart, LinePointEnd, time, LineColor);
	LinePointStart = LinePointEnd
	LinePointEnd = LinePointStart + Vector3(HalfExtents * 2.0, 0, 0)
	DrawLine(LinePointStart, LinePointEnd, time, LineColor);
	LinePointStart = LinePointEnd
	LinePointEnd = LinePointStart + Vector3(0, 0, -HalfExtents * 2.0)
	DrawLine(LinePointStart, LinePointEnd, time, LineColor);
	LinePointStart = LinePointEnd
	LinePointEnd = LinePointStart + Vector3(-HalfExtents * 2.0, 0, 0)
	DrawLine(LinePointStart, LinePointEnd, time, LineColor);

	# Draw vertical lines (four edges connecting top and bottom squares).
	LinePointStart = LinePointEnd
	DrawRay(LinePointStart, Vector3(0, HalfExtents * 2.0, 0),time, LineColor)
	LinePointStart += Vector3(0, 0, HalfExtents * 2.0)
	DrawRay(LinePointStart, Vector3(0, HalfExtents * 2.0, 0), time, LineColor)
	LinePointStart += Vector3(HalfExtents * 2.0, 0, 0)
	DrawRay(LinePointStart, Vector3(0, HalfExtents * 2.0, 0), time, LineColor)
	LinePointStart += Vector3(0, 0, -HalfExtents * 2.0)
	DrawRay(LinePointStart, Vector3(0, HalfExtents * 2.0, 0), time, LineColor)