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docs(physics2d): Primitives

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Syntriax
2024-02-01 12:32:58 +03:00
parent 2b19b24a26
commit 0257911018
6 changed files with 478 additions and 79 deletions
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149
Engine.Physics2D/Primitives/Shape.cs
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@@ -6,22 +6,55 @@ using Syntriax.Engine.Core.Abstract;
namespace Syntriax.Engine.Physics2D.Primitives;
/// <summary>
/// Represents a shape defined by a collection of vertices.
/// </summary>
/// <param name="vertices">The vertices of the shape.</param>
/// <remarks>
/// Initializes a new instance of the <see cref="Shape"/> struct with the specified vertices.
/// </remarks>
[System.Diagnostics.DebuggerDisplay("Vertices Count: {Vertices.Count}")]
public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
public readonly struct Shape(List<Vector2D> vertices) : IEnumerable<Vector2D>
{
public static readonly Shape Triangle = CreateNgon(3, Vector2D.Up);
public static readonly Shape Box = CreateNgon(4, Vector2D.One);
public static readonly Shape Pentagon = CreateNgon(5, Vector2D.Up);
public static readonly Shape Hexagon = CreateNgon(6, Vector2D.Right);
public readonly IList<Vector2D> Vertices { get; init; } = Vertices;
private readonly List<Vector2D> _verticesList = vertices;
/// <summary>
/// Gets the vertices of the shape.
/// </summary>
public IReadOnlyList<Vector2D> Vertices => _verticesList;
/// <summary>
/// The vertex at the specified index.
/// </summary>
/// <param name="index">The zero-based index of the vertex to get or set.</param>
/// <returns>The vertex at the specified index.</returns>
public Vector2D this[System.Index index] => Vertices[index];
/// <summary>
/// Returns a copy of the current shape.
/// </summary>
/// <param name="shape">The shape to copy.</param>
/// <returns>A copy of the input shape.</returns>
public static Shape CreateCopy(Shape shape) => new(new List<Vector2D>(shape.Vertices));
/// <summary>
/// Creates a regular polygon (ngon) with the specified number of vertices.
/// </summary>
/// <param name="vertexCount">The number of vertices in the polygon.</param>
/// <returns>A regular polygon with the specified number of vertices.</returns>
public static Shape CreateNgon(int vertexCount) => CreateNgon(vertexCount, Vector2D.Up);
/// <summary>
/// Creates a regular polygon (ngon) with the specified number of vertices and a rotation position.
/// </summary>
/// <param name="vertexCount">The number of vertices in the polygon.</param>
/// <param name="positionToRotate">The position to use for rotation.</param>
/// <returns>A regular polygon with the specified number of vertices and rotation position.</returns>
public static Shape CreateNgon(int vertexCount, Vector2D positionToRotate)
{
if (vertexCount < 3)
@@ -37,6 +70,11 @@ public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
return new(vertices);
}
/// <summary>
/// Gets the super triangle that encloses the given shape.
/// </summary>
/// <param name="shape">The shape to enclose.</param>
/// <returns>The super triangle that encloses the given shape.</returns>
public static Triangle GetSuperTriangle(Shape shape)
{
float minX = float.MaxValue, minY = float.MaxValue;
@@ -63,6 +101,11 @@ public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
return new Triangle(p1, p2, p3);
}
/// <summary>
/// Gets the lines that form the edges of the shape.
/// </summary>
/// <param name="shape">The shape to get lines from.</param>
/// <param name="lines">The list to populate with lines.</param>
public static void GetLines(Shape shape, IList<Line> lines)
{
lines.Clear();
@@ -71,6 +114,11 @@ public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
lines.Add(new(shape.Vertices[^1], shape.Vertices[0]));
}
/// <summary>
/// Gets a list of lines that form the edges of the shape.
/// </summary>
/// <param name="shape">The shape to get lines from.</param>
/// <returns>A list of lines that form the edges of the shape.</returns>
public static List<Line> GetLines(Shape shape)
{
List<Line> lines = new(shape.Vertices.Count - 1);
@@ -78,6 +126,12 @@ public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
return lines;
}
/// <summary>
/// Projects the shape onto a vector.
/// </summary>
/// <param name="shape">The shape to project.</param>
/// <param name="projectionVector">The vector to project onto.</param>
/// <param name="list">The list to populate with projected values.</param>
public static void Project(Shape shape, Vector2D projectionVector, IList<float> list)
{
list.Clear();
@@ -87,6 +141,12 @@ public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
list.Add(projectionVector.Dot(shape[i]));
}
/// <summary>
/// Projects the shape onto a vector.
/// </summary>
/// <param name="shape">The shape to project.</param>
/// <param name="projectionVector">The vector to project onto.</param>
/// <returns>The projection of the shape onto the vector.</returns>
public static Projection Project(Shape shape, Vector2D projectionVector)
{
float min = float.MaxValue;
@@ -102,6 +162,12 @@ public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
return new(min, max);
}
/// <summary>
/// Transforms the shape using the specified transform.
/// </summary>
/// <param name="shape">The shape to transform.</param>
/// <param name="transform">The transform to apply.</param>
/// <returns>The transformed shape.</returns>
public static Shape TransformShape(Shape shape, ITransform transform)
{
List<Vector2D> vertices = new(shape.Vertices.Count);
@@ -113,15 +179,27 @@ public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
return new Shape(vertices);
}
/// <summary>
/// Transforms the shape using the specified transform.
/// </summary>
/// <param name="from">The shape to transform.</param>
/// <param name="transform">The transform to apply.</param>
/// <param name="to">The transformed shape.</param>
public static void TransformShape(Shape from, ITransform transform, ref Shape to)
{
to.Vertices.Clear();
to._verticesList.Clear();
int count = from.Vertices.Count;
int count = from._verticesList.Count;
for (int i = 0; i < count; i++)
to.Vertices.Add(transform.TransformVector2D(from[i]));
to._verticesList.Add(transform.TransformVector2D(from[i]));
}
/// <summary>
/// Determines whether two shapes are approximately equal.
/// </summary>
/// <param name="left">The first shape to compare.</param>
/// <param name="right">The second shape to compare.</param>
/// <returns><c>true</c> if the shapes are approximately equal; otherwise, <c>false</c>.</returns>
public static bool ApproximatelyEquals(Shape left, Shape right)
{
if (left.Vertices.Count != right.Vertices.Count)
@@ -134,22 +212,83 @@ public readonly struct Shape(IList<Vector2D> Vertices) : IEnumerable<Vector2D>
return true;
}
/// <inheritdoc/>
public IEnumerator<Vector2D> GetEnumerator() => Vertices.GetEnumerator();
/// <inheritdoc/>
IEnumerator IEnumerable.GetEnumerator() => Vertices.GetEnumerator();
}
/// <summary>
/// Provides extension methods for the <see cref="Shape"/> struct.
/// </summary>
public static class ShapeExtensions
{
/// <summary>
/// Creates a copy of the shape.
/// </summary>
/// <param name="shape">The shape to copy.</param>
/// <returns>A copy of the input shape.</returns>
public static Shape CreateCopy(this Shape shape) => Shape.CreateCopy(shape);
/// <summary>
/// Gets the super triangle that encloses the shape.
/// </summary>
/// <param name="shape">The shape to enclose.</param>
/// <returns>The super triangle that encloses the shape.</returns>
public static Triangle ToSuperTriangle(this Shape shape) => Shape.GetSuperTriangle(shape);
/// <summary>
/// Gets the lines that form the edges of the shape.
/// </summary>
/// <param name="shape">The shape to get lines from.</param>
/// <param name="lines">The list to populate with lines.</param>
public static void ToLines(this Shape shape, IList<Line> lines) => Shape.GetLines(shape, lines);
/// <summary>
/// Gets a list of lines that form the edges of the shape.
/// </summary>
/// <param name="shape">The shape to get lines from.</param>
/// <returns>A list of lines that form the edges of the shape.</returns>
public static List<Line> ToLines(this Shape shape) => Shape.GetLines(shape);
/// <summary>
/// Projects the shape onto a vector.
/// </summary>
/// <param name="shape">The shape to project.</param>
/// <param name="projectionVector">The vector to project onto.</param>
/// <param name="list">The list to populate with projected values.</param>
public static void ToProjection(this Shape shape, Vector2D projectionVector, IList<float> list) => Shape.Project(shape, projectionVector, list);
/// <summary>
/// Projects the shape onto a vector.
/// </summary>
/// <param name="shape">The shape to project.</param>
/// <param name="projectionVector">The vector to project onto.</param>
/// <returns>The projection of the shape onto the vector.</returns>
public static Projection ToProjection(this Shape shape, Vector2D projectionVector) => Shape.Project(shape, projectionVector);
/// <summary>
/// Transforms the shape using the specified transform.
/// </summary>
/// <param name="transform">The transform to apply.</param>
/// <param name="shape">The shape to transform.</param>
/// <returns>The transformed shape.</returns>
public static Shape TransformShape(this ITransform transform, Shape shape) => Shape.TransformShape(shape, transform);
/// <summary>
/// Transforms the shape using the specified transform.
/// </summary>
/// <param name="transform">The transform to apply.</param>
/// <param name="from">The shape to transform.</param>
/// <param name="to">The transformed shape.</param>
public static void TransformShape(this ITransform transform, Shape from, ref Shape to) => Shape.TransformShape(from, transform, ref to);
/// <summary>
/// Determines whether two shapes are approximately equal.
/// </summary>
/// <param name="left">The first shape to compare.</param>
/// <param name="right">The second shape to compare.</param>
/// <returns><c>true</c> if the shapes are approximately equal; otherwise, <c>false</c>.</returns>
public static bool ApproximatelyEquals(this Shape left, Shape right) => Shape.ApproximatelyEquals(left, right);
}