MoonTools.Curve/Curve/CubicBezierCurve2D.cs

171 lines
6.4 KiB
C#

using System;
using System.Numerics;
using MoonTools.Core.Curve.Extensions;
namespace MoonTools.Core.Curve
{
/// <summary>
/// A 2-dimensional Bezier curve defined by 4 points.
/// </summary>
public struct CubicBezierCurve2D : IEquatable<CubicBezierCurve2D>
{
/// <summary>
/// The start point.
/// </summary>
public Vector2 P0 { get; }
/// <summary>
/// The first control point.
/// </summary>
public Vector2 P1 { get; }
/// <summary>
/// The second control point.
/// </summary>
public Vector2 P2 { get; }
/// <summary>
/// The end point.
/// </summary>
public Vector2 P3 { get; }
/// <summary>
/// A representation of a 2D cubic Bezier curve.
/// </summary>
/// <param name="p0">The start point.</param>
/// <param name="p1">The first control point.</param>
/// <param name="p2">The second control point.</param>
/// <param name="p3">The end point.</param>
public CubicBezierCurve2D(Vector2 p0, Vector2 p1, Vector2 p2, Vector2 p3)
{
P0 = p0;
P1 = p1;
P2 = p2;
P3 = p3;
}
/// <summary>
/// Returns the curve coordinate given by t.
/// </summary>
/// <param name="t">A value between 0 and 1.</param>
public Vector2 Point(float t) => Point(P0, P1, P2, P3, t);
/// <summary>
/// Returns the curve coordinate given by a normalized time value.
/// </summary>
/// <param name="t">A value between startTime and endTime.</param>
/// <param name="startTime"></param>
/// <param name="endTime"></param>
public Vector2 Point(float t, float startTime, float endTime) => Point(P0, P1, P2, P3, t, startTime, endTime);
/// <summary>
/// Returns the instantaneous velocity on the curve given by t.
/// </summary>
/// <param name="t">A value between 0 and 1.</param>
public Vector2 Velocity(float t) => Velocity(P0, P1, P2, P3, t);
/// <summary>
/// Returns the instantaneous velocity on the curve given by a normalized time value.
/// </summary>
/// <param name="t">A value between startTime and endTime.</param>
/// <param name="startTime"></param>
/// <param name="endTime"></param>
public Vector2 Velocity(float t, float startTime, float endTime) => Velocity(P0, P1, P2, P3, TimeHelper.Normalized(t, startTime, endTime));
/// <summary>
/// Returns the curve coordinate given by 4 points and a time value.
/// </summary>
/// <param name="p0">The start point.</param>
/// <param name="p1">The first control point.</param>
/// <param name="p2">The second control point.</param>
/// <param name="p3">The end point.</param>
/// <param name="t">A value between 0 and 1.</param>
public static Vector2 Point(Vector2 p0, Vector2 p1, Vector2 p2, Vector2 p3, float t)
{
return CubicBezierCurve3D.Point(
new Vector3(p0.X, p0.Y, 0),
new Vector3(p1.X, p1.Y, 0),
new Vector3(p2.X, p2.Y, 0),
new Vector3(p3.X, p3.Y, 0),
t
).XY();
}
/// <summary>
/// Returns the curve coordinate given by 4 points and a normalized time value.
/// </summary>
/// <param name="p0">The start point.</param>
/// <param name="p1">The first control point.</param>
/// <param name="p2">The second control point.</param>
/// <param name="p3">The end point.</param>
/// <param name="t">A value between startTime and endTime.</param>
/// <param name="startTime"></param>
/// <param name="endTime"></param>
public static Vector2 Point(Vector2 p0, Vector2 p1, Vector2 p2, Vector2 p3, float t, float startTime, float endTime)
{
return Point(p0, p1, p2, p3, TimeHelper.Normalized(t, startTime, endTime));
}
/// <summary>
/// Returns the instantaneous velocity given by 4 points and a time value.
/// </summary>
/// <param name="p0">The start point.</param>
/// <param name="p1">The first control point.</param>
/// <param name="p2">The second control point.</param>
/// <param name="p3">The end point.</param>
/// <param name="t">A value between 0 and 1.</param>
public static Vector2 Velocity(Vector2 p0, Vector2 p1, Vector2 p2, Vector2 p3, float t)
{
return CubicBezierCurve3D.Velocity(
new Vector3(p0.X, p0.Y, 0),
new Vector3(p1.X, p1.Y, 0),
new Vector3(p2.X, p2.Y, 0),
new Vector3(p3.X, p3.Y, 0),
t
).XY();
}
/// <summary>
/// Returns the instantaneous velocity given by 4 points and a normalized time value.
/// </summary>
/// <param name="p0">The start point.</param>
/// <param name="p1">The first control point.</param>
/// <param name="p2">The second control point.</param>
/// <param name="p3">The end point.</param>
/// <param name="t">A value between minT and maxT.</param>
/// <param name="minT">The starting time value.</param>
/// <param name="maxT">The ending time value.</param>
public static Vector2 Velocity(Vector2 p0, Vector2 p1, Vector2 p2, Vector2 p3, float t, float minT, float maxT)
{
return Velocity(p0, p1, p2, p3, TimeHelper.Normalized(t, minT, maxT));
}
public override bool Equals(object obj)
{
return obj is CubicBezierCurve2D d && Equals(d);
}
public bool Equals(CubicBezierCurve2D other)
{
return P0.Equals(other.P0) &&
P1.Equals(other.P1) &&
P2.Equals(other.P2) &&
P3.Equals(other.P3);
}
public override int GetHashCode()
{
return HashCode.Combine(P0, P1, P2, P3);
}
public static bool operator ==(CubicBezierCurve2D left, CubicBezierCurve2D right)
{
return left.Equals(right);
}
public static bool operator !=(CubicBezierCurve2D left, CubicBezierCurve2D right)
{
return !(left == right);
}
}
}