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6 Commits

Author SHA1 Message Date
Cat Flynn 74876f3e43 adjust orbit speed 2022-09-05 19:58:32 +01:00
Cat Flynn f31f484dc5 move planet around ellipse 2022-09-05 19:58:32 +01:00
ktyl c5aa808198 implement ellipse 2022-09-05 19:58:32 +01:00
ktyl e128f4e856 draw circle 2022-09-05 19:58:32 +01:00
Cat Flynn 2939b6aded import Vim.Math3d 2022-09-05 19:58:32 +01:00
Cat Flynn 2a4c3b4c88 add camera zoom 2022-09-05 19:58:15 +01:00
13 changed files with 394 additions and 12 deletions

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@ -2,4 +2,7 @@
<PropertyGroup> <PropertyGroup>
<TargetFramework>net472</TargetFramework> <TargetFramework>net472</TargetFramework>
</PropertyGroup> </PropertyGroup>
<ItemGroup>
<PackageReference Include="vim.math3d" Version="1.6.0" />
</ItemGroup>
</Project> </Project>

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@ -1,17 +1,17 @@
[gd_scene load_steps=4 format=2] [gd_scene load_steps=3 format=2]
[ext_resource path="res://scenes/Train.tscn" type="PackedScene" id=1]
[ext_resource path="res://scenes/Railway.tscn" type="PackedScene" id=2]
[ext_resource path="res://scenes/OrbitCamera.tscn" type="PackedScene" id=3] [ext_resource path="res://scenes/OrbitCamera.tscn" type="PackedScene" id=3]
[ext_resource path="res://scenes/orbits/OrbitSystem.tscn" type="PackedScene" id=4]
[node name="Main" type="Node2D"] [node name="Main" type="Node2D"]
[node name="Train" parent="." instance=ExtResource( 1 )]
[node name="DirectionalLight" type="DirectionalLight" parent="."] [node name="DirectionalLight" type="DirectionalLight" parent="."]
transform = Transform( 0.515898, 0.606099, -0.605386, -0.393123, 0.795389, 0.461314, 0.76112, -2.26831e-08, 0.648611, 0, 0, 0 ) transform = Transform( 0.515898, 0.606099, -0.605386, -0.393123, 0.795389, 0.461314, 0.76112, -2.26831e-08, 0.648611, 0, 0, 0 )
[node name="OrbitCamera" parent="." instance=ExtResource( 3 )] [node name="OrbitCamera" parent="." instance=ExtResource( 3 )]
[node name="Railway" parent="." instance=ExtResource( 2 )] [node name="Orbit System" parent="." instance=ExtResource( 4 )]
script = null transform = Transform( 0.856869, 0.3292, -0.396741, 0.0949996, 0.655565, 0.749139, 0.506706, -0.679604, 0.53046, -0.599122, 0, 0 )
SemiMajorAxis = 6.166
Eccentricity = 0.239
_speed = 0.877

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@ -4,7 +4,9 @@
[node name="OrbitCamera" type="Spatial"] [node name="OrbitCamera" type="Spatial"]
script = ExtResource( 1 ) script = ExtResource( 1 )
_zoomSensitivity = 50.0
_cameraPath = NodePath("Camera")
[node name="Camera" type="Camera" parent="."] [node name="Camera" type="Camera" parent="."]
transform = Transform( 1, 0, 0, 0, 0.964146, 0.265371, 0, -0.265371, 0.964146, 0, 2.21115, 9.48434 ) transform = Transform( 1, 0, 0, 0, 0.964146, 0.265371, 0, -0.265371, 0.964146, 0, 7.12726, 27.3456 )
fov = 25.0 fov = 25.0

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@ -0,0 +1,21 @@
[gd_scene load_steps=3 format=2]
[ext_resource path="res://scripts/orbits/OrbitSystem.cs" type="Script" id=1]
[ext_resource path="res://scenes/orbits/Planet.tscn" type="PackedScene" id=2]
[node name="Orbit System" type="Spatial"]
script = ExtResource( 1 )
SemiMajorAxis = 5.994
Eccentricity = 0.518
_a = NodePath("Planet A")
_b = NodePath("Planet B")
_barycenter = NodePath("Barycenter")
[node name="Barycenter" type="Spatial" parent="."]
[node name="Planet A" parent="." instance=ExtResource( 2 )]
transform = Transform( 0.999977, 0.00603502, 0.00319089, -0.00604282, 0.999979, 0.0024369, -0.00317609, -0.00245615, 0.999992, 0, 0, 0 )
[node name="Planet B" parent="." instance=ExtResource( 2 )]
transform = Transform( 0.5, 0, 0, 0, 0.5, 0, 0, 0, 0.5, -6.57314, 0, 4.18169 )
Mass = 0.125

11
scenes/orbits/Planet.tscn Normal file
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@ -0,0 +1,11 @@
[gd_scene load_steps=2 format=2]
[ext_resource path="res://scripts/orbits/Planet.cs" type="Script" id=1]
[node name="Planet" type="Spatial"]
script = ExtResource( 1 )
Mass = 1.0
[node name="CSGSphere" type="CSGSphere" parent="."]
radial_segments = 20
rings = 20

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@ -4,7 +4,25 @@ using System;
public class OrbitCamera : Spatial public class OrbitCamera : Spatial
{ {
[Export] [Export]
private float _sensitivity = 200f; private float _lookSensitivity = 200f;
[Export]
private float _zoomSensitivity = 10f;
[Export]
private NodePath _cameraPath;
private Camera _camera = null;
private Camera Camera
{
get
{
if (_camera == null)
{
_camera = GetNode<Camera>(_cameraPath);
}
return _camera;
}
}
private Vector2 _rotation; private Vector2 _rotation;
private bool _canRotate = false; private bool _canRotate = false;
@ -24,7 +42,8 @@ public class OrbitCamera : Spatial
public override void _Process(float delta) public override void _Process(float delta)
{ {
Rotation = Vector3.Zero; Rotation = Vector3.Zero;
var sensitivity = -1f / _sensitivity; var sensitivity = -1f / _lookSensitivity;
Rotate(Vector3.Right, _rotation.y * sensitivity); Rotate(Vector3.Right, _rotation.y * sensitivity);
Rotate(Vector3.Up, _rotation.x * sensitivity); Rotate(Vector3.Up, _rotation.x * sensitivity);
} }
@ -32,9 +51,23 @@ public class OrbitCamera : Spatial
// left click to drag // left click to drag
private void HandleMouseButton(InputEventMouseButton mouseButton) private void HandleMouseButton(InputEventMouseButton mouseButton)
{ {
if (mouseButton.ButtonIndex != (int)ButtonList.Left) return; switch ((ButtonList)mouseButton.ButtonIndex)
{
case ButtonList.Left:
_canRotate = mouseButton.Pressed; _canRotate = mouseButton.Pressed;
break;
case ButtonList.WheelUp:
Zoom(-1);
break;
case ButtonList.WheelDown:
Zoom(1);
break;
}
}
private void Zoom(float amount)
{
Camera.Fov += amount * _zoomSensitivity / Camera.Fov;
} }
private void HandleMouseMovement(InputEventMouseMotion mouseMotion) private void HandleMouseMovement(InputEventMouseMotion mouseMotion)

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@ -0,0 +1,6 @@
using Vim.Math3d;
public interface ILocation
{
DVector3 Position { get; set; }
}

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@ -0,0 +1,7 @@
using Godot;
using System;
public interface IMassive
{
float Mass { get; }
}

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@ -0,0 +1,3 @@
public interface IPointMass : IMassive, ILocation
{
}

48
scripts/orbits/Orbit.cs Normal file
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@ -0,0 +1,48 @@
using Godot;
using System;
using Vim.Math3d;
public class Orbit
{
// the position of the primary body relative to the ellipse - the
// orbit itself is presented as being centred on the primary, but
// all our math is ellipse stuff
private DVector2 PrimaryPosition => Ellipse.Focus0;
public Ellipse Ellipse { get; set; }
public DVector3 GetPosition(float t)
{
var p = PrimaryPosition + Ellipse.GetPosition(t);
return new DVector3(p.X, 0, p.Y);
}
public void Draw(ImmediateGeometry geo)
{
geo.Clear();
geo.Begin(Mesh.PrimitiveType.LineLoop);
DrawEllipse(geo);
geo.End();
}
private void DrawEllipse(ImmediateGeometry geo)
{
geo.SetColor(new Color(1, 0, 0));
int steps = 100;
for (int i = 0; i < steps; i++)
{
float t = i / (float)steps;
float a = t * Mathf.Tau;
var v2 = Ellipse.Focus0 + Ellipse.GetPosition(a);
geo.AddVertex(new Godot.Vector3
{
x = (float)v2.X,
z = (float)v2.Y
});
}
}
}

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@ -0,0 +1,153 @@
using Godot;
using System;
using Vim.Math3d;
[Tool]
public class OrbitSystem : Node, IMassive, ILocation
{
[Export] private NodePath _a;
[Export] private NodePath _b;
[Export] private NodePath _barycenter;
private double _semiMajorAxis;
[Export]
private double SemiMajorAxis
{
get => _semiMajorAxis;
set
{
_semiMajorAxis = value;
if (!Engine.EditorHint) return;
InvalidateGeometry();
}
}
private double _eccentricity;
[Export(PropertyHint.Range, "0,1")]
private double Eccentricity
{
get => _eccentricity;
set
{
_eccentricity = value;
if (!Engine.EditorHint) return;
InvalidateGeometry();
}
}
#region Point Masses
private IPointMass Primary
{
get
{
if (_pointMasses[0] == null)
{
InitPointMasses();
}
return _pointMasses[0];
}
}
private IPointMass Secondary
{
get
{
if (_pointMasses[1] == null)
{
InitPointMasses();
}
return _pointMasses[1];
}
}
private readonly IPointMass[] _pointMasses = new IPointMass[2];
private void InitPointMasses()
{
var a = GetNode<IPointMass>(_a);
var b = GetNode<IPointMass>(_b);
if (a.Mass > b.Mass)
{
_pointMasses[0] = a;
_pointMasses[1] = b;
}
else
{
_pointMasses[0] = b;
_pointMasses[1] = a;
}
}
#endregion
public float Mass => Primary.Mass + Secondary.Mass;
public DVector3 Position
{
get => Barycenter;
set => Barycenter = value;
}
public DVector3 Barycenter
{
get
{
var p0 = Primary.Position;
var p1 = Secondary.Position;
return p0.Lerp(p1, .5f);
}
// TODO - make setting the berycenter do something sensible?
set => _ = value;
}
private Orbit _orbit = null;
private Orbit Orbit
{
get
{
if (_orbit == null)
{
_orbit = new Orbit();
}
return _orbit;
}
}
private ImmediateGeometry _orbitGeometry = null;
public ImmediateGeometry OrbitGeometry
{
get
{
if (_orbitGeometry == null)
{
_orbitGeometry = new ImmediateGeometry();
var m = new SpatialMaterial();
m.VertexColorUseAsAlbedo = true;
m.FlagsUnshaded = true;
_orbitGeometry.MaterialOverride = m;
AddChild(_orbitGeometry);
}
return _orbitGeometry;
}
}
private float _time = 0;
[Export]
private float _speed = 3f;
public override void _Process(float delta)
{
_time += delta * _speed;
InvalidateGeometry();
}
private void InvalidateGeometry()
{
Orbit.Ellipse = new Ellipse(SemiMajorAxis, Eccentricity);
Orbit.Draw(OrbitGeometry);
Secondary.Position = Orbit.GetPosition(_time);
}
}

32
scripts/orbits/Planet.cs Normal file
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@ -0,0 +1,32 @@
using Godot;
using System;
using Vim.Math3d;
[Tool]
public class Planet : Spatial, IPointMass
{
[Export]
public float Mass { get; set; }
private DVector3? _position;
public DVector3 Position
{
get
{
if (_position.HasValue) return _position.Value;
var t = Translation;
return new DVector3(t.x, t.y, t.z);
}
set
{
_position = value;
Translation = new Godot.Vector3
{
x = (float)value.X,
y = (float)value.Y,
z = (float)value.Z
};
}
}
}

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@ -0,0 +1,63 @@
using Godot;
using System;
using Vim.Math3d;
public struct Ellipse
{
public Ellipse(double a = 1, double e = 0)
{
SemiMajorAxis = a;
Eccentricity = e;
// TODO: this is an immutable struct, so initialise everything else
// in the constructor to avoid recalculating properties whenever
// they are accessed
}
/// <summary>
/// Semi-major axis
/// </summary>
public double a => SemiMajorAxis;
public double SemiMajorAxis { get; }
/// <summary>
/// Eccentricity
/// </summary>
public double e => Eccentricity;
public double Eccentricity { get; }
/// <summary>
/// Semi-minor axis
/// </summary>
public double b => SemiMinorAxis;
public double SemiMinorAxis => Math.Sqrt(Apisides.max * Apisides.min);
/// <summary>
/// Get a position on the auxiliary circle
/// </summary>
/// <param name="t">Angle in radians around the circle</param>
/// <returns>2D position on the circle scaled by the semi-major axis</returns>
public DVector2 GetAuxiliaryPosition2D(double t = 0) =>
new DVector2(Math.Cos(t), Math.Sin(t)) * a;
private Apisides Apisides => new Apisides(a, e);
public DVector2 GetPosition(double t) =>
new DVector2(Math.Cos(t) * a, Math.Sin(t) * b);
public DVector2 Focus0 => new DVector2(-GetFocusDistance(), 0);
public DVector2 Focus1 => new DVector2(GetFocusDistance(), 0);
private double GetFocusDistance() => Math.Sqrt(a * a - b * b);
}
public struct Apisides
{
public readonly double min;
public readonly double max;
public Apisides(double a, double e)
{
min = a * (1 - e);
max = a * (1 + e);
}
}