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