Added engine force, air resistance, and rolling resistance

also added debug draw 3d addon

addons/debug_draw_3d/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 DmitriySalnikov
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the Software), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, andor sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

addons/debug_draw_3d/README.md

@@ -0,0 +1,157 @@
+![icon](/images/icon_3d_128.png)
+
+# Debug drawing utility for Godot
+
+This is an add-on for debug drawing in 3D and for some 2D overlays, which is written in `C++` and can be used with `GDScript` or `C#`.
+
+Based on my previous addon, which was developed [only for C#](https://github.com/DmitriySalnikov/godot_debug_draw_cs), and which was inspired by [Zylann's GDScript addon](https://github.com/Zylann/godot_debug_draw)
+
+## [Documentation](https://dd3d.dmitriysalnikov.ru/docs/)
+
+## [Godot 3 version](https://github.com/DmitriySalnikov/godot_debug_draw_3d/tree/godot_3)
+
+## Support me
+
+Your support adds motivation to develop my public projects.
+
+<a href="https://boosty.to/dmitriysalnikov/donate"><img src="/docs/images/boosty.png" alt="Boosty" width=150px/></a>
+
+<a href="#"><img src="/docs/images/USDT-TRC20.png" alt="USDT-TRC20" width=150px/></a>
+
+<b>USDT-TRC20 TEw934PrsffHsAn5M63SoHYRuZo984EF6v</b>
+
+## Features
+
+3D:
+
+* Arrow
+* Billboard opaque square
+* Box
+* Camera Frustum
+* Cylinder
+* Gizmo
+* Grid
+* Line
+* Line Path
+* Line with Arrow
+* Plane
+* Points
+* Position 3D (3 crossing axes)
+* Sphere
+* 3D Text
+
+2D:
+
+* **[Work in progress]**
+
+Overlay:
+
+* Text (with grouping and coloring)
+
+Precompiled for:
+
+* Windows
+* Linux (built on Ubuntu 22.04)
+* macOS (10.15+)
+* Android (5.0+)
+* iOS
+* Web (Firefox is supported by Godot 4.3+)
+
+This addon supports working with several World3D and different Viewports.
+There is also a no depth test mode and other settings that can be changed for each instance.
+
+This library supports double-precision builds, for more information, [see the documentation](https://dd3d.dmitriysalnikov.ru/docs/?page=md_docs_2DoublePrecision.html).
+
+## [Interactive Web Demo](https://dd3d.dmitriysalnikov.ru/demo/)
+
+[![screenshot_web](/images/screenshot_web.png)](https://dd3d.dmitriysalnikov.ru/demo/)
+
+## Download
+
+To download, use the [Godot Asset Library](https://godotengine.org/asset-library/asset/1766) or use one of the stable versions from the [GitHub Releases](https://github.com/DmitriySalnikov/godot_debug_draw_3d/releases) page.
+
+For versions prior to `1.4.5`, just download one of the `source codes` in the assets. For newer versions, download `debug-draw-3d_[version].zip`.
+
+### Installation
+
+* Close editor
+* Copy `addons/debug_draw_3d` to your `addons` folder, create it if the folder doesn't exist
+* Launch editor
+
+## Examples
+
+More examples can be found in the `examples_dd3d/` folder.
+
+Simple test:
+
+```gdscript
+func _process(delta: float) -> void:
+	var _time = Time.get_ticks_msec() / 1000.0
+	var box_pos = Vector3(0, sin(_time * 4), 0)
+	var line_begin = Vector3(-1, sin(_time * 4), 0)
+	var line_end = Vector3(1, cos(_time * 4), 0)
+
+	DebugDraw3D.draw_box(box_pos, Quaternion.IDENTITY, Vector3(1, 2, 1), Color(0, 1, 0))
+	DebugDraw3D.draw_line(line_begin, line_end, Color(1, 1, 0))
+	DebugDraw2D.set_text("Time", _time)
+	DebugDraw2D.set_text("Frames drawn", Engine.get_frames_drawn())
+	DebugDraw2D.set_text("FPS", Engine.get_frames_per_second())
+	DebugDraw2D.set_text("delta", delta)
+```
+
+![screenshot_1](/images/screenshot_1.png)
+
+An example of using scoped configs:
+
+```gdscript
+@tool
+extends Node3D
+
+func _ready():
+	# Set the base scoped_config.
+	# Each frame will be reset to these scoped values.
+	DebugDraw3D.scoped_config().set_thickness(0.1).set_center_brightness(0.6)
+
+func _process(delta):
+	# Draw using the base scoped config.
+	DebugDraw3D.draw_box(Vector3.ZERO, Quaternion.IDENTITY, Vector3.ONE * 2, Color.CORNFLOWER_BLUE)
+	if true:
+		# Create a scoped config that will exist until exiting this if.
+		var _s = DebugDraw3D.new_scoped_config().set_thickness(0).set_center_brightness(0.1)
+		# Draw with a thickness of 0
+		DebugDraw3D.draw_box(Vector3.ZERO, Quaternion.IDENTITY, Vector3.ONE, Color.RED)
+		# If necessary, the values inside this scope can be changed
+		# even before each call to draw_*.
+		_s.set_thickness(0.05)
+		DebugDraw3D.draw_box(Vector3(1,0,1), Quaternion.IDENTITY, Vector3.ONE * 1, Color.BLUE_VIOLET)
+```
+
+![screenshot_5](/images/screenshot_5.png)
+
+> [!TIP]
+>
+> If you want to use a non-standard Viewport for rendering a 3d scene, then do not forget to specify it in the scoped config!
+
+## API
+
+This project has a separate [documentation](https://dd3d.dmitriysalnikov.ru/docs/) page.
+
+Also, a list of all functions is available in the documentation inside the editor (see `DebugDraw3D` and `DebugDraw2D`).
+
+![screenshot_4](/images/screenshot_4.png)
+
+## Known issues and limitations
+
+The text in the keys and values of a text group cannot contain multi-line strings.
+
+The entire text overlay can only be placed in one corner.
+
+[Frustum of Camera3D does not take into account the window size from ProjectSettings](https://github.com/godotengine/godot/issues/70362).
+
+## More screenshots
+
+`DebugDrawDemoScene.tscn` in editor
+![screenshot_2](/images/screenshot_2.png)
+
+`DebugDrawDemoScene.tscn` in play mode
+![screenshot_3](/images/screenshot_3.png)

addons/debug_draw_3d/debug_draw_3d.gdextension

@@ -0,0 +1,153 @@
+[configuration]
+
+entry_symbol = "debug_draw_3d_library_init"
+compatibility_minimum = "4.2.2"
+reloadable = false
+
+[dependencies]
+
+; example.x86_64 = { "relative or absolute path to the dependency" : "the path relative to the exported project", }
+; -------------------------------------
+; debug
+
+macos = { }
+windows.x86_64 = { }
+linux.x86_64 = { }
+
+; by default godot is using threads
+web.wasm32.nothreads = {}
+web.wasm32 = {}
+
+android.arm32 = { }
+android.arm64 = { }
+android.x86_32 = { }
+android.x86_64 = { }
+
+ios = {}
+
+; -------------------------------------
+; release no debug draw
+
+macos.template_release = { }
+windows.template_release.x86_64 = { }
+linux.template_release.x86_64 = { }
+
+web.template_release.wasm32.nothreads = { }
+web.template_release.wasm32 = { }
+
+android.template_release.arm32 = { }
+android.template_release.arm64 = { }
+android.template_release.x86_32 = { }
+android.template_release.x86_64 = { }
+
+ios.template_release = {}
+
+; -------------------------------------
+; release forced debug draw
+
+macos.template_release.forced_dd3d = { }
+windows.template_release.x86_64.forced_dd3d = { }
+linux.template_release.x86_64.forced_dd3d = { }
+
+web.template_release.wasm32.nothreads.forced_dd3d = { }
+web.template_release.wasm32.forced_dd3d = { }
+
+ios.template_release.forced_dd3d = {}
+
+[libraries]
+
+; -------------------------------------
+; debug
+
+macos = "libs/libdd3d.macos.editor.universal.framework"
+windows.x86_64 = "libs/libdd3d.windows.editor.x86_64.dll"
+linux.x86_64 = "libs/libdd3d.linux.editor.x86_64.so"
+
+web.wasm32.nothreads = "libs/libdd3d.web.template_debug.wasm32.wasm"
+web.wasm32 = "libs/libdd3d.web.template_debug.wasm32.threads.wasm"
+
+android.arm32 = "libs/libdd3d.android.template_debug.arm32.so"
+android.arm64 = "libs/libdd3d.android.template_debug.arm64.so"
+android.x86_32 = "libs/libdd3d.android.template_debug.x86_32.so"
+android.x86_64 = "libs/libdd3d.android.template_debug.x86_64.so"
+
+ios = "libs/libdd3d.ios.template_debug.universal.dylib"
+
+; -------------------------------------
+; release no debug draw
+
+macos.template_release = "libs/libdd3d.macos.template_release.universal.framework"
+windows.template_release.x86_64 = "libs/libdd3d.windows.template_release.x86_64.dll"
+linux.template_release.x86_64 = "libs/libdd3d.linux.template_release.x86_64.so"
+
+web.template_release.wasm32.nothreads = "libs/libdd3d.web.template_release.wasm32.wasm"
+web.template_release.wasm32 = "libs/libdd3d.web.template_release.wasm32.threads.wasm"
+
+android.template_release.arm32 = "libs/libdd3d.android.template_release.arm32.so"
+android.template_release.arm64 = "libs/libdd3d.android.template_release.arm64.so"
+android.template_release.x86_32 = "libs/libdd3d.android.template_release.x86_32.so"
+android.template_release.x86_64 = "libs/libdd3d.android.template_release.x86_64.so"
+
+ios.template_release = "libs/libdd3d.ios.template_release.universal.dylib"
+
+; -------------------------------------
+; release forced debug draw
+
+macos.template_release.forced_dd3d = "libs/libdd3d.macos.template_release.universal.enabled.framework"
+windows.template_release.x86_64.forced_dd3d = "libs/libdd3d.windows.template_release.x86_64.enabled.dll"
+linux.template_release.x86_64.forced_dd3d = "libs/libdd3d.linux.template_release.x86_64.enabled.so"
+
+web.template_release.wasm32.nothreads.forced_dd3d = "libs/libdd3d.web.template_release.wasm32.enabled.wasm"
+web.template_release.wasm32.forced_dd3d = "libs/libdd3d.web.template_release.wasm32.threads.enabled.wasm"
+
+ios.template_release.forced_dd3d = "libs/libdd3d.ios.template_release.universal.enabled.dylib"
+
+; -------------------------------------
+; DOUBLE PRECISION
+; -------------------------------------
+
+; -------------------------------------
+; debug
+
+macos.double = "libs/libdd3d.macos.editor.universal.double.framework"
+windows.x86_64.double = "libs/libdd3d.windows.editor.x86_64.double.dll"
+linux.x86_64.double = "libs/libdd3d.linux.editor.x86_64.double.so"
+
+web.wasm32.nothreads.double = "libs/libdd3d.web.template_debug.wasm32.double.wasm"
+web.wasm32.double = "libs/libdd3d.web.template_debug.wasm32.threads.double.wasm"
+
+android.arm32.double = "libs/libdd3d.android.template_debug.arm32.double.so"
+android.arm64.double = "libs/libdd3d.android.template_debug.arm64.double.so"
+android.x86_32.double = "libs/libdd3d.android.template_debug.x86_32.double.so"
+android.x86_64.double = "libs/libdd3d.android.template_debug.x86_64.double.so"
+
+ios.double = "libs/libdd3d.ios.template_debug.universal.dylib"
+
+; -------------------------------------
+; release no debug draw
+
+macos.template_release.double = "libs/libdd3d.macos.template_release.universal.double.framework"
+windows.template_release.x86_64.double = "libs/libdd3d.windows.template_release.x86_64.double.dll"
+linux.template_release.x86_64.double = "libs/libdd3d.linux.template_release.x86_64.double.so"
+
+web.template_release.wasm32.nothreads.double = "libs/libdd3d.web.template_release.wasm32.double.wasm"
+web.template_release.wasm32.double = "libs/libdd3d.web.template_release.wasm32.threads.double.wasm"
+
+android.template_release.arm32.double = "libs/libdd3d.android.template_release.arm32.double.so"
+android.template_release.arm64.double = "libs/libdd3d.android.template_release.arm64.double.so"
+android.template_release.x86_32.double = "libs/libdd3d.android.template_release.x86_32.double.so"
+android.template_release.x86_64.double = "libs/libdd3d.android.template_release.x86_64.double.so"
+
+ios.template_release.double = "libs/libdd3d.ios.template_release.universal.double.dylib"
+
+; -------------------------------------
+; release forced debug draw
+
+macos.template_release.forced_dd3d.double = "libs/libdd3d.macos.template_release.universal.enabled.double.framework"
+windows.template_release.x86_64.forced_dd3d.double = "libs/libdd3d.windows.template_release.x86_64.enabled.double.dll"
+linux.template_release.x86_64.forced_dd3d.double = "libs/libdd3d.linux.template_release.x86_64.enabled.double.so"
+
+web.template_release.wasm32.nothreads.forced_dd3d.double = "libs/libdd3d.web.template_release.wasm32.enabled.double.wasm"
+web.template_release.wasm32.forced_dd3d.double = "libs/libdd3d.web.template_release.wasm32.threads.enabled.double.wasm"
+
+ios.template_release.forced_dd3d.double = "libs/libdd3d.ios.template_release.universal.enabled.double.dylib"

addons/debug_draw_3d/debug_draw_3d.gdextension.uid

@@ -0,0 +1 @@
+uid://svqaxfp5kyrl

addons/debug_draw_3d/libs/libdd3d.macos.editor.universal.framework/Resources/Info.plist

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>libdd3d.macos.editor.universal.dylib</string>
+	<key>CFBundleName</key>
+	<string>Debug Draw 3D</string>
+	<key>CFBundleDisplayName</key>
+	<string>Debug Draw 3D</string>
+	<key>CFBundleIdentifier</key>
+	<string>ru.dmitriysalnikov.dd3d</string>
+	<key>NSHumanReadableCopyright</key>
+	<string>Copyright (c) Dmitriy Salnikov.</string>
+	<key>CFBundleVersion</key>
+	<string>1.5.1</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.5.1</string>
+	<key>CFBundlePackageType</key>
+	<string>FMWK</string>
+	<key>CSResourcesFileMapped</key>
+	<true/>
+	<key>DTPlatformName</key>
+	<string>macosx</string>
+	<key>LSMinimumSystemVersion</key>
+	<string>10.14</string>
+	<key>CFBundleSupportedPlatforms</key>
+	<array>
+		<string>MacOSX</string>
+	</array>
+</dict>
+</plist>
+    

addons/debug_draw_3d/libs/libdd3d.macos.template_release.universal.enabled.framework/Resources/Info.plist

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>libdd3d.macos.template_release.universal.enabled.dylib</string>
+	<key>CFBundleName</key>
+	<string>Debug Draw 3D</string>
+	<key>CFBundleDisplayName</key>
+	<string>Debug Draw 3D</string>
+	<key>CFBundleIdentifier</key>
+	<string>ru.dmitriysalnikov.dd3d</string>
+	<key>NSHumanReadableCopyright</key>
+	<string>Copyright (c) Dmitriy Salnikov.</string>
+	<key>CFBundleVersion</key>
+	<string>1.5.1</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.5.1</string>
+	<key>CFBundlePackageType</key>
+	<string>FMWK</string>
+	<key>CSResourcesFileMapped</key>
+	<true/>
+	<key>DTPlatformName</key>
+	<string>macosx</string>
+	<key>LSMinimumSystemVersion</key>
+	<string>10.14</string>
+	<key>CFBundleSupportedPlatforms</key>
+	<array>
+		<string>MacOSX</string>
+	</array>
+</dict>
+</plist>
+    

addons/debug_draw_3d/libs/libdd3d.macos.template_release.universal.framework/Resources/Info.plist

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>libdd3d.macos.template_release.universal.dylib</string>
+	<key>CFBundleName</key>
+	<string>Debug Draw 3D</string>
+	<key>CFBundleDisplayName</key>
+	<string>Debug Draw 3D</string>
+	<key>CFBundleIdentifier</key>
+	<string>ru.dmitriysalnikov.dd3d</string>
+	<key>NSHumanReadableCopyright</key>
+	<string>Copyright (c) Dmitriy Salnikov.</string>
+	<key>CFBundleVersion</key>
+	<string>1.5.1</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.5.1</string>
+	<key>CFBundlePackageType</key>
+	<string>FMWK</string>
+	<key>CSResourcesFileMapped</key>
+	<true/>
+	<key>DTPlatformName</key>
+	<string>macosx</string>
+	<key>LSMinimumSystemVersion</key>
+	<string>10.14</string>
+	<key>CFBundleSupportedPlatforms</key>
+	<array>
+		<string>MacOSX</string>
+	</array>
+</dict>
+</plist>
+    

car.gd

@@ -1,6 +1,10 @@
 class_name Car
 extends RigidBody3D
 
+## X axis is RPM, Y axis is torque in NM
+@export var torque_curve: Curve
+@export var air_resistance: float = .3
+
 @export_group("Steering")
 ## Maximum angle of imaginary wheel at center front of the car
 @export var max_steer_angle: float = 30
@@ -18,11 +22,15 @@ extends RigidBody3D
 @onready var track: float = front_right.position.distance_to(front_left.position)
 
 var current_steer_angle: float = 0
+var rpm: float = 0
+
+func _ready() -> void:
+	for wheel: Wheel in wheels:
+		wheel.set_new_car(self)
 
 func _physics_process(delta: float) -> void:
 	steer(delta)
-	for wheel: Wheel in wheels:
-		wheel.apply_forces(self)
+	apply_air_resistance()
 
 func steer(delta: float) -> void:
 	var steer_input = Input.get_axis("Steer Right", "Steer Left")
@@ -44,6 +52,25 @@ func steer(delta: float) -> void:
 		front_right.rotation.y = -inner_angle
 		front_left.rotation.y = -outer_angle
 
-##Point argument is in local space
+func apply_air_resistance() -> void:
+	var force: Vector3 = air_resistance * linear_velocity * linear_velocity.length()
+	apply_force(force, center_of_mass)
+	DebugDraw3D.draw_arrow(
+		to_global(center_of_mass),
+		to_global(center_of_mass) + force,
+		Color.YELLOW,
+		.2
+	)
+
+##Point argument is in global space
 func get_velocity_at_point(point: Vector3) -> Vector3:
-	return linear_velocity + angular_velocity.cross(point - center_of_mass)
+	return linear_velocity + angular_velocity.cross(to_local(point) - center_of_mass)
+
+## Returns torque in NM, per wheel on the drive train
+func get_torque_per_wheel() -> float:
+	var is_powered: Callable = func (wheel: Wheel) -> bool: return wheel.on_drivetrain
+	var powered_wheel_count: int = wheels.filter(is_powered).size()
+	if 0 < powered_wheel_count:
+		var engine_torque: float = Input.get_action_strength("Accelerate") * torque_curve.sample_baked(rpm)
+		return engine_torque / powered_wheel_count
+	return 0.0 

car.tscn

@@ -1,15 +1,21 @@
-[gd_scene load_steps=5 format=3 uid="uid://dklnyvh2pawj1"]
+[gd_scene load_steps=6 format=3 uid="uid://dklnyvh2pawj1"]
 
 [ext_resource type="PackedScene" uid="uid://b4q25yxjds0hu" path="res://RX-Car.glb" id="1_7822p"]
 [ext_resource type="Script" uid="uid://brdagffuckrxo" path="res://car.gd" id="1_uoj53"]
 [ext_resource type="PackedScene" uid="uid://cqcmml6o1x724" path="res://wheel.tscn" id="3_k61xc"]
 
+[sub_resource type="Curve" id="Curve_k61xc"]
+_limits = [0.0, 500.0, 0.0, 10000.0]
+_data = [Vector2(0, 303.40942), 0.0, 0.0, 0, 0, Vector2(4272.152, 489.27692), 0.0, 0.0, 0, 0, Vector2(8554.853, 31.756958), 0.0, 0.0, 0, 0]
+point_count = 3
+
 [sub_resource type="ConvexPolygonShape3D" id="ConvexPolygonShape3D_7822p"]
 points = PackedVector3Array(2.639865, -0.93180054, 2.1575794, 2.5861135, 1.1470379, -1.4858942, 2.3804116, 0.5341828, 5.2797356, 2.3804116, 0.18806255, 5.32922, 2.3804116, -0.8661753, 4.864291, 2.3804116, -1.0148906, 4.0564213, 2.6011019, -0.9791671, 0.85025597, 2.590765, -0.8667045, -2.7230182, 2.590765, -0.28533888, -2.7966702, 1.4661236, 1.6421381, -0.30746174, 1.4661236, 1.6421381, 1.965394, 2.2072706, 0.77604365, 5.2682266, 2.4093547, -0.27607727, -5.989025, 2.3804116, 0.40134466, -4.392848, 2.2186413, 0.11079419, -5.824459, 1.82481, 0.6985105, -5.445842, 2.3230424, -0.08025998, 5.6525984, 2.212439, -0.45231283, 5.6169233, 0.3802452, -0.5354029, 5.61232, -2.3812249, -0.8661753, 4.864291, -2.3812249, -1.0148906, 4.0564213, 2.3804116, -1.0148906, -4.7944813, 2.3804116, -0.9804902, -5.7243385, 0.8805454, 1.6670123, -0.30746174, 1.7379808, 0.72020924, -5.445842, 1.0908988, 0.8818908, -5.445842, 0.8805454, 1.6670123, 1.965394, 0.9823625, 1.0935851, 5.340728, 1.5581212, 1.056274, 5.295847, 2.2506852, -0.2766065, -5.998232, 1.3152068, -0.28031117, -6.0511694, 0.3802452, -0.28401583, -6.102956, 0.3802452, -0.05273974, 5.649146, -2.310418, -0.08025998, 5.6537495, -0.38105845, -0.5354029, 5.61232, -2.1574335, -0.42452794, 5.6169233, -2.3812249, 0.18806255, 5.32922, -2.640161, -0.93180054, 2.1575794, -2.601915, -0.9791671, 0.85025597, -2.3812249, -1.0148906, -4.7944813, -2.3812249, -0.9804902, -5.7243385, 0.3802452, -0.4711007, -6.001684, 0.3802452, 1.6881818, -0.30746174, -1.0917118, 0.8818908, -5.445842, -0.38105845, 1.6884462, -0.30746174, 0.3802452, 1.6881818, 1.965394, -0.98317564, 1.0935851, 5.340728, -0.38105845, 1.6884462, 1.965394, -0.38105845, -0.28401583, -6.102956, -0.38105845, -0.05273974, 5.649146, -2.3812249, 0.5341828, 5.2797356, -2.3812249, 0.4148401, 5.296997, -1.559451, 1.056274, 5.295847, -2.2086005, 0.77604365, 5.2682266, -2.5869267, 1.1470379, -1.4858942, -2.5920951, -0.28533888, -2.7966702, -2.5920951, -0.8667045, -2.7230182, -2.415853, -0.28401583, -6.0488677, -2.390011, -0.7981685, -5.8094983, -1.3129189, -0.28401583, -6.0787888, -0.38105845, -0.4711007, -6.001684, -2.3176537, -0.08661085, -5.9372387, -2.2194543, 0.11079419, -5.824459, -1.739311, 0.72020924, -5.445842, -1.4669368, 1.6421381, -0.30746174, -1.4669368, 1.6421381, 1.965394, -1.825623, 0.6985105, -5.445842, -2.3812249, 0.40134466, -4.392848)
 
 [node name="Car" type="RigidBody3D" node_paths=PackedStringArray("front_right", "front_left", "back_right", "back_left")]
 mass = 1000.0
 script = ExtResource("1_uoj53")
+torque_curve = SubResource("Curve_k61xc")
 front_right = NodePath("WheelFR")
 front_left = NodePath("WheelFL")
 back_right = NodePath("WheelRR")
@@ -25,6 +31,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -0.5505377, 0.29083502, -2.04
 [node name="WheelRR" parent="." instance=ExtResource("3_k61xc")]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0.883119, -0.15691829, 0.9406)
 flipped = true
+on_drivetrain = true
 
 [node name="WheelFR" parent="." instance=ExtResource("3_k61xc")]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0.883119, -0.13746506, -1.6053799)
@@ -35,3 +42,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -0.9021299, -0.15691829, -1.6
 
 [node name="WheelRL" parent="." instance=ExtResource("3_k61xc")]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -0.9021299, -0.13746506, 0.9405999)
+on_drivetrain = true
+
+[node name="Camera3D" type="Camera3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 0.9641093, 0.26550564, 0, -0.26550564, 0.9641093, 0, 1.8623276, 4.216471)

default_bus_layout.tres

@@ -0,0 +1,3 @@
+[gd_resource type="AudioBusLayout" format=3 uid="uid://di20fp68vrg8a"]
+
+[resource]

main.tscn

@@ -31,9 +31,6 @@ shadow_enabled = true
 [node name="WorldEnvironment" type="WorldEnvironment" parent="."]
 environment = SubResource("Environment_0xm2m")
 
-[node name="Camera3D" type="Camera3D" parent="."]
-transform = Transform3D(0.96653086, -0.21564756, -0.1389759, 0.12064472, -0.09602227, 0.98804075, -0.22641337, -0.97173876, -0.06679173, -2.64523, 9.843718, -35.668438)
-
 [node name="CSGBox3D2" type="CSGBox3D" parent="."]
 transform = Transform3D(-1.0000001, 0, 0, 0, -1.0000001, 0, 0, 0, 1, -5.7605286, 1.5558312, -35.098152)
 material_override = SubResource("StandardMaterial3D_0xm2m")

project.godot

@@ -15,6 +15,10 @@ run/main_scene="res://main.tscn"
 config/features=PackedStringArray("4.5", "Forward Plus")
 config/icon="res://icon.svg"
 
+[debug_draw_3d]
+
+settings/addon_root_folder="res://addons/debug_draw_3d"
+
 [display]
 
 window/stretch/mode="viewport"
@@ -31,6 +35,11 @@ window/stretch/mode="viewport"
 "events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":65,"key_label":0,"unicode":97,"location":0,"echo":false,"script":null)
 ]
 }
+Accelerate={
+"deadzone": 0.2,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":87,"key_label":0,"unicode":119,"location":0,"echo":false,"script":null)
+]
+}
 
 [physics]
 

wheel.gd

@@ -3,40 +3,98 @@ extends RayCast3D
 
 @export var wheel_radius: float = 0.316
 @export var flipped: bool = false
+@export var on_drivetrain: bool = false
+@export var rolling_resistance: float = 2
 @export_group("Suspension")
 @export var suspension_rest_length: float = 0.1
 @export var suspension_stiffness: float = 30_000
 @export var suspension_damping: float = 2000
 
+var car: Car
+var _last_velocity: Vector3
+
 func _ready() -> void:
 	target_position *= suspension_rest_length + wheel_radius
 	$"RX-Wheel".rotate_y(PI if flipped else 0.0)
 
-func apply_forces(car: Car) -> void:
+func set_new_car(new_car: Car) -> void:
+	car = new_car
+	# Little bit freaky but we put up with it
+	_last_velocity = car.get_velocity_at_point(get_collision_point())
+
+func _physics_process(_delta: float) -> void:
 	force_raycast_update()
 	
-	var force: Vector3 = get_suspension_force(car)
-	car.apply_force(force, car.to_local(get_collision_point()))
+	apply_suspension_force()
+	apply_rolling_resistance()
+	apply_engine_force()
+	_last_velocity = car.get_velocity_at_point(get_collision_point())
 
-func get_suspension_force(car: Car) -> Vector3:
+func apply_suspension_force() -> void:
 	var up: Vector3 = global_basis.y
 	if not is_colliding():
 		$"RX-Wheel".position = -up * suspension_rest_length
-		return Vector3.ZERO
+		return
 	
-	var collision_point: Vector3 = to_local(get_collision_point())
-	var wheel_center: Vector3 = collision_point + (up * wheel_radius)
+	var wheel_center: Vector3 = get_wheel_center()
 	$"RX-Wheel".position = wheel_center
 	var suspension_length: float = -up.dot(wheel_center)
 	var suspension_displacement: float = suspension_rest_length - suspension_length
 	#https://en.wikipedia.org/wiki/Hookes_law
 	var hookes_force_scalar: float = suspension_stiffness * suspension_displacement
 	
-	var wheel_velocity: Vector3 = car.get_velocity_at_point(car.to_local(to_global(wheel_center)))
+	var wheel_velocity: Vector3 = car.get_velocity_at_point(to_global(wheel_center))
 	var wheel_up_velocity: float = up.dot(wheel_velocity)
 	var damping_force_scalar: float = suspension_damping * wheel_up_velocity
 	
 	var y_force_scalar: float = hookes_force_scalar - damping_force_scalar
-	var force: Vector3 = Vector3.UP * y_force_scalar
+	var force: Vector3 = up * y_force_scalar
 	
-	return force
+	DebugDraw3D.draw_arrow(
+		to_global(wheel_center),
+		to_global(wheel_center + force / 1000),
+		Color.RED,
+		.2
+	)
+	car.apply_force(force, car.to_local(to_global(wheel_center)))
+
+func apply_rolling_resistance() -> void:
+	if not is_colliding(): return
+	
+	var normal: Vector3 = get_collision_normal()
+	
+	var velocity: Vector3 = car.get_velocity_at_point(get_collision_point())
+	velocity -= normal * normal.dot(velocity)
+	var force: Vector3 = -rolling_resistance * velocity
+	var arrow_tail: Vector3 = to_global(get_wheel_center())
+	
+	car.apply_force(force, car.to_local(get_collision_point()))
+	DebugDraw3D.draw_arrow(
+		arrow_tail,
+		arrow_tail + force,
+		Color.ORANGE,
+		.2
+	)
+
+func apply_engine_force() -> void:
+	if not on_drivetrain: return
+	if not is_colliding(): return
+	
+	var forwards: Vector3 = -global_basis.z
+	
+	var torque: float = car.get_torque_per_wheel()
+	var force: Vector3 = forwards * torque / wheel_radius
+	
+	var arrow_tail: Vector3 = to_global(get_wheel_center())
+	car.apply_force(force, car.to_local(get_collision_point()))
+	DebugDraw3D.draw_arrow(
+		arrow_tail,
+		arrow_tail + force / 250,
+		Color.BLUE,
+		.2
+	)
+
+func get_wheel_center() -> Vector3:
+	var up: Vector3 = global_basis.y
+	var collision_point: Vector3 = to_local(get_collision_point())
+	return collision_point + (up * wheel_radius)