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Collision API (#17)

main
cosmonaut 2022-03-24 06:07:34 +00:00
parent cc876b2132
commit 80c34c6b16
16 changed files with 1225 additions and 9 deletions
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144
src/Collision/AABB2D.cs Normal file
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using System.Collections.Generic;
using MoonWorks.Math;
namespace MoonWorks.Collision
{
/// <summary>
/// Axis-aligned bounding box.
/// </summary>
public struct AABB2D : System.IEquatable<AABB2D>
{
/// <summary>
/// The top-left position of the AABB.
/// </summary>
/// <value></value>
public Vector2 Min { get; private set; }
/// <summary>
/// The bottom-right position of the AABB.
/// </summary>
/// <value></value>
public Vector2 Max { get; private set; }
public float Width { get { return Max.X - Min.X; } }
public float Height { get { return Max.Y - Min.Y; } }
public float Right { get { return Max.X; } }
public float Left { get { return Min.X; } }
/// <summary>
/// The top of the AABB. Assumes a downward-aligned Y axis, so this value will be smaller than Bottom.
/// </summary>
/// <value></value>
public float Top { get { return Min.Y; } }
/// <summary>
/// The bottom of the AABB. Assumes a downward-aligned Y axis, so this value will be larger than Top.
/// </summary>
/// <value></value>
public float Bottom { get { return Max.Y; } }
public AABB2D(float minX, float minY, float maxX, float maxY)
{
Min = new Vector2(minX, minY);
Max = new Vector2(maxX, maxY);
}
public AABB2D(Vector2 min, Vector2 max)
{
Min = min;
Max = max;
}
private static Matrix3x2 AbsoluteMatrix(Matrix3x2 matrix)
{
return new Matrix3x2
(
System.Math.Abs(matrix.M11), System.Math.Abs(matrix.M12),
System.Math.Abs(matrix.M21), System.Math.Abs(matrix.M22),
System.Math.Abs(matrix.M31), System.Math.Abs(matrix.M32)
);
}
/// <summary>
/// Efficiently transforms the AABB by a Transform2D.
/// </summary>
/// <param name="aabb"></param>
/// <param name="transform"></param>
/// <returns></returns>
public static AABB2D Transformed(AABB2D aabb, Transform2D transform)
{
return new AABB2D(
Vector2.Transform(aabb.Min, transform.TransformMatrix),
Vector2.Transform(aabb.Max, transform.TransformMatrix)
);
}
/// <summary>
/// Creates an AABB for an arbitrary collection of positions.
/// This is less efficient than defining a custom AABB method for most shapes, so avoid using this if possible.
/// </summary>
/// <param name="vertices"></param>
/// <returns></returns>
public static AABB2D FromVertices(IEnumerable<Vector2> vertices)
{
var minX = float.MaxValue;
var minY = float.MaxValue;
var maxX = float.MinValue;
var maxY = float.MinValue;
foreach (var vertex in vertices)
{
if (vertex.X < minX)
{
minX = vertex.X;
}
if (vertex.Y < minY)
{
minY = vertex.Y;
}
if (vertex.X > maxX)
{
maxX = vertex.X;
}
if (vertex.Y > maxY)
{
maxY = vertex.Y;
}
}
return new AABB2D(minX, minY, maxX, maxY);
}
public static bool TestOverlap(AABB2D a, AABB2D b)
{
return a.Left <= b.Right && a.Right >= b.Left && a.Top <= b.Bottom && a.Bottom >= b.Top;
}
public override bool Equals(object obj)
{
return obj is AABB2D aabb && Equals(aabb);
}
public bool Equals(AABB2D other)
{
return Min == other.Min &&
Max == other.Max;
}
public override int GetHashCode()
{
return System.HashCode.Combine(Min, Max);
}
public static bool operator ==(AABB2D left, AABB2D right)
{
return left.Equals(right);
}
public static bool operator !=(AABB2D left, AABB2D right)
{
return !(left == right);
}
}
}

16
src/Collision/IHasAABB2D.cs Normal file
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using MoonWorks.Math;
namespace MoonWorks.Collision
{
public interface IHasAABB2D
{
AABB2D AABB { get; }
/// <summary>
/// Returns a bounding box based on the shape.
/// </summary>
/// <param name="transform">A Transform for transforming the shape vertices.</param>
/// <returns>Returns a bounding box based on the shape.</returns>
AABB2D TransformedAABB(Transform2D transform);
}
}

15
src/Collision/IShape2D.cs Normal file
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using MoonWorks.Math;
namespace MoonWorks.Collision
{
public interface IShape2D : IHasAABB2D, System.IEquatable<IShape2D>
{
/// <summary>
/// A Minkowski support function. Gives the farthest point on the edge of a shape along the given direction.
/// </summary>
/// <param name="direction">A normalized Vector2.</param>
/// <param name="transform">A Transform for transforming the shape vertices.</param>
/// <returns>The farthest point on the edge of the shape along the given direction.</returns>
Vector2 Support(Vector2 direction, Transform2D transform);
}
}

57
src/Collision/MinkowskiDifference.cs Normal file
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using MoonWorks.Math;
namespace MoonWorks.Collision
{
/// <summary>
/// A Minkowski difference between two shapes.
/// </summary>
public struct MinkowskiDifference : System.IEquatable<MinkowskiDifference>
{
private IShape2D ShapeA { get; }
private Transform2D TransformA { get; }
private IShape2D ShapeB { get; }
private Transform2D TransformB { get; }
public MinkowskiDifference(IShape2D shapeA, Transform2D transformA, IShape2D shapeB, Transform2D transformB)
{
ShapeA = shapeA;
TransformA = transformA;
ShapeB = shapeB;
TransformB = transformB;
}
public Vector2 Support(Vector2 direction)
{
return ShapeA.Support(direction, TransformA) - ShapeB.Support(-direction, TransformB);
}
public override bool Equals(object other)
{
return other is MinkowskiDifference minkowskiDifference && Equals(minkowskiDifference);
}
public bool Equals(MinkowskiDifference other)
{
return
ShapeA == other.ShapeA &&
TransformA == other.TransformA &&
ShapeB == other.ShapeB &&
TransformB == other.TransformB;
}
public override int GetHashCode()
{
return System.HashCode.Combine(ShapeA, TransformA, ShapeB, TransformB);
}
public static bool operator ==(MinkowskiDifference a, MinkowskiDifference b)
{
return a.Equals(b);
}
public static bool operator !=(MinkowskiDifference a, MinkowskiDifference b)
{
return !(a == b);
}
}
}

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src/Collision/NarrowPhase.cs Normal file
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using MoonWorks.Math;
namespace MoonWorks.Collision
{
public static class NarrowPhase
{
private struct Edge
{
public float Distance;
public Vector2 Normal;
public int Index;
}
public static bool TestCollision(IShape2D shapeA, Transform2D transformA, IShape2D shapeB, Transform2D transformB)
{
if (shapeA is Rectangle rectangleA && shapeB is Rectangle rectangleB && transformA.Rotation == 0 && transformB.Rotation == 0)
{
return TestRectangleOverlap(rectangleA, transformA, rectangleB, transformB);
}
else if (shapeA is Point && shapeB is Rectangle && transformB.Rotation == 0)
{
return TestPointRectangleOverlap((Point) shapeA, transformA, (Rectangle) shapeB, transformB);
}
else if (shapeA is Rectangle && shapeB is Point && transformA.Rotation == 0)
{
return TestPointRectangleOverlap((Point) shapeB, transformB, (Rectangle) shapeA, transformA);
}
else if (shapeA is Circle circleA && shapeB is Circle circleB && transformA.Scale.X == transformA.Scale.Y && transformB.Scale.X == transformB.Scale.Y)
{
return TestCircleOverlap(circleA, transformA, circleB, transformB);
}
return FindCollisionSimplex(shapeA, transformA, shapeB, transformB).Item1;
}
public static bool TestRectangleOverlap(Rectangle rectangleA, Transform2D transformA, Rectangle rectangleB, Transform2D transformB)
{
var firstAABB = rectangleA.TransformedAABB(transformA);
var secondAABB = rectangleB.TransformedAABB(transformB);
return firstAABB.Left < secondAABB.Right && firstAABB.Right > secondAABB.Left && firstAABB.Top < secondAABB.Bottom && firstAABB.Bottom > secondAABB.Top;
}
public static bool TestPointRectangleOverlap(Point point, Transform2D pointTransform, Rectangle rectangle, Transform2D rectangleTransform)
{
var transformedPoint = pointTransform.Position;
var AABB = rectangle.TransformedAABB(rectangleTransform);
return transformedPoint.X > AABB.Left && transformedPoint.X < AABB.Right && transformedPoint.Y < AABB.Bottom && transformedPoint.Y > AABB.Top;
}
public static bool TestCircleOverlap(Circle circleA, Transform2D transformA, Circle circleB, Transform2D transformB)
{
var radiusA = circleA.Radius * transformA.Scale.X;
var radiusB = circleB.Radius * transformB.Scale.Y;
var centerA = transformA.Position;
var centerB = transformB.Position;
var distanceSquared = (centerA - centerB).LengthSquared();
var radiusSumSquared = (radiusA + radiusB) * (radiusA + radiusB);
return distanceSquared < radiusSumSquared;
}
public static (bool, Simplex2D) FindCollisionSimplex(IShape2D shapeA, Transform2D transformA, IShape2D shapeB, Transform2D transformB)
{
var minkowskiDifference = new MinkowskiDifference(shapeA, transformA, shapeB, transformB);
var c = minkowskiDifference.Support(Vector2.UnitX);
var b = minkowskiDifference.Support(-Vector2.UnitX);
return Check(minkowskiDifference, c, b);
}
public unsafe static Vector2 Intersect(IShape2D shapeA, Transform2D Transform2DA, IShape2D shapeB, Transform2D Transform2DB, Simplex2D simplex)
{
if (shapeA == null) { throw new System.ArgumentNullException(nameof(shapeA)); }
if (shapeB == null) { throw new System.ArgumentNullException(nameof(shapeB)); }
if (!simplex.TwoSimplex) { throw new System.ArgumentException("Simplex must be a 2-Simplex.", nameof(simplex)); }
var a = simplex.A;
var b = simplex.B.Value;
var c = simplex.C.Value;
Vector2 intersection = default;
for (var i = 0; i < 32; i++)
{
var edge = FindClosestEdge(simplex);
var support = CalculateSupport(shapeA, Transform2DA, shapeB, Transform2DB, edge.Normal);
var distance = Vector2.Dot(support, edge.Normal);
intersection = edge.Normal;
intersection *= distance;
if (System.Math.Abs(distance - edge.Distance) <= 0.00001f)
{
return intersection;
}
else
{
simplex.Insert(support, edge.Index);
}
}
return intersection; // close enough
}
private static unsafe Edge FindClosestEdge(Simplex2D simplex)
{
var closestDistance = float.PositiveInfinity;
var closestNormal = Vector2.Zero;
var closestIndex = 0;
for (var i = 0; i < 4; i += 1)
{
var j = (i + 1 == 3) ? 0 : i + 1;
var a = simplex[i];
var b = simplex[j];
var e = b - a;
var oa = a;
var n = Vector2.Normalize(TripleProduct(e, oa, e));
var d = Vector2.Dot(n, a);
if (d < closestDistance)
{
closestDistance = d;
closestNormal = n;
closestIndex = j;
}
}
return new Edge
{
Distance = closestDistance,
Normal = closestNormal,
Index = closestIndex
};
}
private static Vector2 CalculateSupport(IShape2D shapeA, Transform2D Transform2DA, IShape2D shapeB, Transform2D Transform2DB, Vector2 direction)
{
return shapeA.Support(direction, Transform2DA) - shapeB.Support(-direction, Transform2DB);
}
private static (bool, Simplex2D) Check(MinkowskiDifference minkowskiDifference, Vector2 c, Vector2 b)
{
var cb = c - b;
var c0 = -c;
var d = Direction(cb, c0);
return DoSimplex(minkowskiDifference, new Simplex2D(b, c), d);
}
private static (bool, Simplex2D) DoSimplex(MinkowskiDifference minkowskiDifference, Simplex2D simplex, Vector2 direction)
{
var a = minkowskiDifference.Support(direction);
var notPastOrigin = Vector2.Dot(a, direction) < 0;
var (intersects, newSimplex, newDirection) = EnclosesOrigin(a, simplex);
if (notPastOrigin)
{
return (false, default(Simplex2D));
}
else if (intersects)
{
return (true, new Simplex2D(simplex.A, simplex.B.Value, a));
}
else
{
return DoSimplex(minkowskiDifference, newSimplex, newDirection);
}
}
private static (bool, Simplex2D, Vector2) EnclosesOrigin(Vector2 a, Simplex2D simplex)
{
if (simplex.ZeroSimplex)
{
return HandleZeroSimplex(a, simplex.A);
}
else if (simplex.OneSimplex)
{
return HandleOneSimplex(a, simplex.A, simplex.B.Value);
}
else
{
return (false, simplex, Vector2.Zero);
}
}
private static (bool, Simplex2D, Vector2) HandleZeroSimplex(Vector2 a, Vector2 b)
{
var ab = b - a;
var a0 = -a;
var (newSimplex, newDirection) = SameDirection(ab, a0) ? (new Simplex2D(a, b), Perpendicular(ab, a0)) : (new Simplex2D(a), a0);
return (false, newSimplex, newDirection);
}
private static (bool, Simplex2D, Vector2) HandleOneSimplex(Vector2 a, Vector2 b, Vector2 c)
{
var a0 = -a;
var ab = b - a;
var ac = c - a;
var abp = Perpendicular(ab, -ac);
var acp = Perpendicular(ac, -ab);
if (SameDirection(abp, a0))
{
if (SameDirection(ab, a0))
{
return (false, new Simplex2D(a, b), abp);
}
else
{
return (false, new Simplex2D(a), a0);
}
}
else if (SameDirection(acp, a0))
{
if (SameDirection(ac, a0))
{
return (false, new Simplex2D(a, c), acp);
}
else
{
return (false, new Simplex2D(a), a0);
}
}
else
{
return (true, new Simplex2D(b, c), a0);
}
}
private static Vector2 TripleProduct(Vector2 a, Vector2 b, Vector2 c)
{
var A = new Vector3(a.X, a.Y, 0);
var B = new Vector3(b.X, b.Y, 0);
var C = new Vector3(c.X, c.Y, 0);
var first = Vector3.Cross(A, B);
var second = Vector3.Cross(first, C);
return new Vector2(second.X, second.Y);
}
private static Vector2 Direction(Vector2 a, Vector2 b)
{
var d = TripleProduct(a, b, a);
var collinear = d == Vector2.Zero;
return collinear ? new Vector2(a.Y, -a.X) : d;
}
private static bool SameDirection(Vector2 a, Vector2 b)
{
return Vector2.Dot(a, b) > 0;
}
private static Vector2 Perpendicular(Vector2 a, Vector2 b)
{
return TripleProduct(a, b, a);
}
}
}

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src/Collision/Shapes/Circle.cs Normal file
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using MoonWorks.Math;
namespace MoonWorks.Collision
{
/// <summary>
/// A Circle is a shape defined by a radius.
/// </summary>
public struct Circle : IShape2D, System.IEquatable<Circle>
{
public int Radius { get; }
public AABB2D AABB { get; }
public Circle(int radius)
{
Radius = radius;
AABB = new AABB2D(-Radius, -Radius, Radius, Radius);
}
public Vector2 Support(Vector2 direction, Transform2D transform)
{
return Vector2.Transform(Vector2.Normalize(direction) * Radius, transform.TransformMatrix);
}
public AABB2D TransformedAABB(Transform2D transform2D)
{
return AABB2D.Transformed(AABB, transform2D);
}
public override bool Equals(object obj)
{
return obj is IShape2D other && Equals(other);
}
public bool Equals(IShape2D other)
{
return other is Circle circle && Equals(circle);
}
public bool Equals(Circle other)
{
return Radius == other.Radius;
}
public override int GetHashCode()
{
return System.HashCode.Combine(Radius);
}
public static bool operator ==(Circle a, Circle b)
{
return a.Equals(b);
}
public static bool operator !=(Circle a, Circle b)
{
return !(a == b);
}
}
}

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src/Collision/Shapes/Line.cs Normal file
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using MoonWorks.Math;
namespace MoonWorks.Collision
{
/// <summary>
/// A line is a shape defined by exactly two points in space.
/// </summary>
public struct Line : IShape2D, System.IEquatable<Line>
{
private Vector2 Start { get; }
private Vector2 End { get; }
public AABB2D AABB { get; }
public Line(Vector2 start, Vector2 end)
{
Start = start;
End = end;
AABB = new AABB2D(
System.Math.Min(Start.X, End.X),
System.Math.Min(Start.Y, End.Y),
System.Math.Max(Start.X, End.X),
System.Math.Max(Start.Y, End.Y)
);
}
public Vector2 Support(Vector2 direction, Transform2D transform)
{
var transformedStart = Vector2.Transform(Start, transform.TransformMatrix);
var transformedEnd = Vector2.Transform(End, transform.TransformMatrix);
return Vector2.Dot(transformedStart, direction) > Vector2.Dot(transformedEnd, direction) ?
transformedStart :
transformedEnd;
}
public AABB2D TransformedAABB(Transform2D transform)
{
return AABB2D.Transformed(AABB, transform);
}
public override bool Equals(object obj)
{
return obj is IShape2D other && Equals(other);
}
public bool Equals(IShape2D other)
{
return other is Line otherLine && Equals(otherLine);
}
public bool Equals(Line other)
{
return
(Start == other.Start && End == other.End) ||
(End == other.Start && Start == other.End);
}
public override int GetHashCode()
{
return System.HashCode.Combine(Start, End);
}
public static bool operator ==(Line a, Line b)
{
return a.Equals(b);
}
public static bool operator !=(Line a, Line b)
{
return !(a == b);
}
}
}

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src/Collision/Shapes/Point.cs Normal file
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using MoonWorks.Math;
namespace MoonWorks.Collision
{
/// <summary>
/// A Point is "that which has no part".
/// All points by themselves are identical.
/// </summary>
public struct Point : IShape2D, System.IEquatable<Point>
{
public AABB2D AABB { get; }
public AABB2D TransformedAABB(Transform2D transform)
{
return AABB2D.Transformed(AABB, transform);
}
public Vector2 Support(Vector2 direction, Transform2D transform)
{
return Vector2.Transform(Vector2.Zero, transform.TransformMatrix);
}
public override bool Equals(object obj)
{
return obj is IShape2D other && Equals(other);
}
public bool Equals(IShape2D other)
{
return other is Point otherPoint && Equals(otherPoint);
}
public bool Equals(Point other)
{
return true;
}
public override int GetHashCode()
{
return 0;
}
public static bool operator ==(Point a, Point b)
{
return true;
}
public static bool operator !=(Point a, Point b)
{
return false;
}
}
}

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src/Collision/Shapes/Rectangle.cs Normal file
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using MoonWorks.Math;
namespace MoonWorks.Collision
{
/// <summary>
/// A rectangle is a shape defined by a width and height. The origin is the center of the rectangle.
/// </summary>
public struct Rectangle : IShape2D, System.IEquatable<Rectangle>
{
public AABB2D AABB { get; }
public int Width { get; }
public int Height { get; }
public float Right { get; }
public float Left { get; }
public float Top { get; }
public float Bottom { get; }
public Vector2 BottomLeft { get; }
public Vector2 TopRight { get; }
public Vector2 Min { get; }
public Vector2 Max { get; }
public Rectangle(int left, int top, int width, int height)
{
Width = width;
Height = height;
Left = left;
Right = left + width;
Top = top;
Bottom = top + height;
AABB = new AABB2D(left, top, Right, Bottom);
BottomLeft = new Vector2(Left, Bottom);
TopRight = new Vector2(Top, Right);
Min = AABB.Min;
Max = AABB.Max;
}
private Vector2 Support(Vector2 direction)
{
if (direction.X >= 0 && direction.Y >= 0)
{
return Max;
}
else if (direction.X >= 0 && direction.Y < 0)
{
return new Vector2(Max.X, Min.Y);
}
else if (direction.X < 0 && direction.Y >= 0)
{
return new Vector2(Min.X, Max.Y);
}
else if (direction.X < 0 && direction.Y < 0)
{
return new Vector2(Min.X, Min.Y);
}
else
{
throw new System.ArgumentException("Support vector direction cannot be zero.");
}
}
public Vector2 Support(Vector2 direction, Transform2D transform)
{
Matrix3x2 inverseTransform;
Matrix3x2.Invert(transform.TransformMatrix, out inverseTransform);
var inverseDirection = Vector2.TransformNormal(direction, inverseTransform);
return Vector2.Transform(Support(inverseDirection), transform.TransformMatrix);
}
public AABB2D TransformedAABB(Transform2D transform)
{
return AABB2D.Transformed(AABB, transform);
}
public override bool Equals(object obj)
{
return obj is IShape2D other && Equals(other);
}
public bool Equals(IShape2D other)
{
return (other is Rectangle rectangle && Equals(rectangle));
}
public bool Equals(Rectangle other)
{
return Min == other.Min && Max == other.Max;
}
public override int GetHashCode()
{
return System.HashCode.Combine(Min, Max);
}
public static bool operator ==(Rectangle a, Rectangle b)
{
return a.Equals(b);
}
public static bool operator !=(Rectangle a, Rectangle b)
{
return !(a == b);
}
}
}

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using System.Collections.Generic;
using MoonWorks.Math;
namespace MoonWorks.Collision
{
/// <summary>
/// A simplex is a shape with up to n - 2 vertices in the nth dimension.
/// </summary>
public struct Simplex2D : System.IEquatable<Simplex2D>
{
private Vector2 a;
private Vector2? b;
private Vector2? c;
public Vector2 A => a;
public Vector2? B => b;
public Vector2? C => c;
public bool ZeroSimplex { get { return !b.HasValue && !c.HasValue; } }
public bool OneSimplex { get { return b.HasValue && !c.HasValue; } }
public bool TwoSimplex { get { return b.HasValue && c.HasValue; } }
public int Count => TwoSimplex ? 3 : (OneSimplex ? 2 : 1);
public Simplex2D(Vector2 a)
{
this.a = a;
b = null;
c = null;
}
public Simplex2D(Vector2 a, Vector2 b)
{
this.a = a;
this.b = b;
c = null;
}
public Simplex2D(Vector2 a, Vector2 b, Vector2 c)
{
this.a = a;
this.b = b;
this.c = c;
}
public Vector2 this[int index]
{
get
{
if (index == 0) { return a; }
if (index == 1) { return b.Value; }
if (index == 2) { return c.Value; }
throw new System.IndexOutOfRangeException();
}
}
public IEnumerable<Vector2> Vertices
{
get
{
yield return (Vector2) a;
if (b.HasValue) { yield return (Vector2) b; }
if (c.HasValue) { yield return (Vector2) c; }
}
}
public Vector2 Support(Vector2 direction, Transform2D transform)
{
var maxDotProduct = float.NegativeInfinity;
var maxVertex = a;
foreach (var vertex in Vertices)
{
var transformed = Vector2.Transform(vertex, transform.TransformMatrix);
var dot = Vector2.Dot(transformed, direction);
if (dot > maxDotProduct)
{
maxVertex = transformed;
maxDotProduct = dot;
}
}
return maxVertex;
}
public void Insert(Vector2 point, int index)
{
if (index == 0)
{
c = b;
b = a;
a = point;
}
else if (index == 1)
{
c = b;
b = point;
}
else
{
c = point;
}
}
public override bool Equals(object obj)
{
return obj is Simplex2D other && Equals(other);
}
public bool Equals(Simplex2D other)
{
if (Count != other.Count) { return false; }
return
(A == other.A && B == other.B && C == other.C) ||
(A == other.A && B == other.C && C == other.B) ||
(A == other.B && B == other.A && C == other.C) ||
(A == other.B && B == other.C && C == other.A) ||
(A == other.C && B == other.A && C == other.B) ||
(A == other.C && B == other.B && C == other.A);
}
public override int GetHashCode()
{
return System.HashCode.Combine(Vertices);
}
public static bool operator ==(Simplex2D a, Simplex2D b)
{
return a.Equals(b);
}
public static bool operator !=(Simplex2D a, Simplex2D b)
{
return !(a == b);
}
}
}

187
src/Collision/SpatialHash2D.cs Normal file
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@ -0,0 +1,187 @@
using System.Collections.Generic;
using MoonWorks.Math;
namespace MoonWorks.Collision
{
/// <summary>
/// Used to quickly check if two shapes are potentially overlapping.
/// </summary>
/// <typeparam name="T">The type that will be used to uniquely identify shape-transform pairs.</typeparam>
public class SpatialHash2D<T> where T : System.IEquatable<T>
{
private readonly int cellSize;
private readonly Dictionary<long, HashSet<T>> hashDictionary = new Dictionary<long, HashSet<T>>();
private readonly Dictionary<T, (IHasAABB2D, Transform2D)> IDLookup = new Dictionary<T, (IHasAABB2D, Transform2D)>();
public int MinX { get; private set; } = 0;
public int MaxX { get; private set; } = 0;
public int MinY { get; private set; } = 0;
public int MaxY { get; private set; } = 0;
private Queue<HashSet<T>> hashSetPool = new Queue<HashSet<T>>();
public SpatialHash2D(int cellSize)
{
this.cellSize = cellSize;
}
private (int, int) Hash(Vector2 position)
{
return ((int) System.Math.Floor(position.X / cellSize), (int) System.Math.Floor(position.Y / cellSize));
}
/// <summary>
/// Inserts an element into the SpatialHash.
/// </summary>
/// <param name="id">A unique ID for the shape-transform pair.</param>
/// <param name="shape"></param>
/// <param name="transform2D"></param>
public void Insert(T id, IHasAABB2D shape, Transform2D transform2D)
{
var box = shape.TransformedAABB(transform2D);
var minHash = Hash(box.Min);
var maxHash = Hash(box.Max);
for (var i = minHash.Item1; i <= maxHash.Item1; i++)
{
for (var j = minHash.Item2; j <= maxHash.Item2; j++)
{
var key = MakeLong(i, j);
if (!hashDictionary.ContainsKey(key))
{
hashDictionary.Add(key, new HashSet<T>());
}
hashDictionary[key].Add(id);
IDLookup[id] = (shape, transform2D);
}
}
MinX = System.Math.Min(MinX, minHash.Item1);
MinY = System.Math.Min(MinY, minHash.Item2);
MaxX = System.Math.Max(MaxX, maxHash.Item1);
MaxY = System.Math.Max(MaxY, maxHash.Item2);
}
/// <summary>
/// Retrieves all the potential collisions of a shape-transform pair. Excludes any shape-transforms with the given ID.
/// </summary>
public IEnumerable<(T, IHasAABB2D, Transform2D)> Retrieve(T id, IHasAABB2D shape, Transform2D transform2D)
{
var returned = AcquireHashSet();
var box = shape.TransformedAABB(transform2D);
var (minX, minY) = Hash(box.Min);
var (maxX, maxY) = Hash(box.Max);
if (minX < MinX) { minX = MinX; }
if (maxX > MaxX) { maxX = MaxX; }
if (minY < MinY) { minY = MinY; }
if (maxY > MaxY) { maxY = MaxY; }
for (var i = minX; i <= maxX; i++)
{
for (var j = minY; j <= maxY; j++)
{
var key = MakeLong(i, j);
if (hashDictionary.ContainsKey(key))
{
foreach (var t in hashDictionary[key])
{
if (!returned.Contains(t))
{
var (otherShape, otherTransform) = IDLookup[t];
if (!id.Equals(t) && AABB2D.TestOverlap(box, otherShape.TransformedAABB(otherTransform)))
{
returned.Add(t);
yield return (t, otherShape, otherTransform);
}
}
}
}
}
}
FreeHashSet(returned);
}
/// <summary>
/// Retrieves objects based on a pre-transformed AABB.
/// </summary>
/// <param name="aabb">A transformed AABB.</param>
/// <returns></returns>
public IEnumerable<(T, IHasAABB2D, Transform2D)> Retrieve(AABB2D aabb)
{
var returned = AcquireHashSet();
var (minX, minY) = Hash(aabb.Min);
var (maxX, maxY) = Hash(aabb.Max);
if (minX < MinX) { minX = MinX; }
if (maxX > MaxX) { maxX = MaxX; }
if (minY < MinY) { minY = MinY; }
if (maxY > MaxY) { maxY = MaxY; }
for (var i = minX; i <= maxX; i++)
{
for (var j = minY; j <= maxY; j++)
{
var key = MakeLong(i, j);
if (hashDictionary.ContainsKey(key))
{
foreach (var t in hashDictionary[key])
{
if (!returned.Contains(t))
{
var (otherShape, otherTransform) = IDLookup[t];
if (AABB2D.TestOverlap(aabb, otherShape.TransformedAABB(otherTransform)))
{
yield return (t, otherShape, otherTransform);
}
}
}
}
}
}
FreeHashSet(returned);
}
/// <summary>
/// Removes everything that has been inserted into the SpatialHash.
/// </summary>
public void Clear()
{
foreach (var hash in hashDictionary.Values)
{
hash.Clear();
}
IDLookup.Clear();
}
private static long MakeLong(int left, int right)
{
return ((long) left << 32) | ((uint) right);
}
private HashSet<T> AcquireHashSet()
{
if (hashSetPool.Count == 0)
{
hashSetPool.Enqueue(new HashSet<T>());
}
var hashSet = hashSetPool.Dequeue();
hashSet.Clear();
return hashSet;
}
private void FreeHashSet(HashSet<T> hashSet)
{
hashSetPool.Enqueue(hashSet);
}
}
}

2
src/Graphics/Resources/Texture.cs
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@ -199,6 +199,8 @@ namespace MoonWorks.Graphics
UsageFlags = textureCreateInfo.UsageFlags; UsageFlags = textureCreateInfo.UsageFlags;
} }
public static implicit operator TextureSlice(Texture t) => new TextureSlice(t);
// Used by AcquireSwapchainTexture. // Used by AcquireSwapchainTexture.
// Should not be tracked, because swapchain textures are managed by Vulkan. // Should not be tracked, because swapchain textures are managed by Vulkan.
internal Texture( internal Texture(

9
src/Input/Gamepad.cs
View File

@ -89,14 +89,14 @@ namespace MoonWorks.Input
foreach (var (sdlEnum, axis) in EnumToAxis) foreach (var (sdlEnum, axis) in EnumToAxis)
{ {
var sdlAxisValue = SDL.SDL_GameControllerGetAxis(Handle, sdlEnum); var sdlAxisValue = SDL.SDL_GameControllerGetAxis(Handle, sdlEnum);
var axisValue = Normalize(sdlAxisValue, short.MinValue, short.MaxValue, -1, 1); var axisValue = MathHelper.Normalize(sdlAxisValue, short.MinValue, short.MaxValue, -1, 1);
axis.Update(axisValue); axis.Update(axisValue);
} }
foreach (var (sdlEnum, trigger) in EnumToTrigger) foreach (var (sdlEnum, trigger) in EnumToTrigger)
{ {
var sdlAxisValue = SDL.SDL_GameControllerGetAxis(Handle, sdlEnum); var sdlAxisValue = SDL.SDL_GameControllerGetAxis(Handle, sdlEnum);
var axisValue = Normalize(sdlAxisValue, 0, short.MaxValue, 0, 1); var axisValue = MathHelper.Normalize(sdlAxisValue, 0, short.MaxValue, 0, 1);
trigger.Update(axisValue); trigger.Update(axisValue);
} }
} }
@ -177,10 +177,5 @@ namespace MoonWorks.Input
{ {
return MoonWorks.Conversions.ByteToBool(SDL.SDL_GameControllerGetButton(Handle, button)); return MoonWorks.Conversions.ByteToBool(SDL.SDL_GameControllerGetButton(Handle, button));
} }
private float Normalize(float value, short min, short max, short newMin, short newMax)
{
return ((value - min) * (newMax - newMin)) / (max - min) + newMin;
}
} }
} }

10
src/Math/MathHelper.cs
View File

@ -331,6 +331,16 @@ namespace MoonWorks.Math
return angle; return angle;
} }
public static float Normalize(float value, short min, short max, short newMin, short newMax)
{
return ((value - min) * (newMax - newMin)) / (max - min) + newMin;
}
public static float Normalize(float value, float min, float max, float newMin, float newMax)
{
return ((value - min) * (newMax - newMin)) / (max - min) + newMin;
}
#endregion #endregion
#region Internal Static Methods #region Internal Static Methods

82
src/Math/Transform2D.cs Normal file
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@ -0,0 +1,82 @@
namespace MoonWorks.Math
{
public struct Transform2D : System.IEquatable<Transform2D>
{
public Vector2 Position { get; }
public float Rotation { get; }
public Vector2 Scale { get; }
public Matrix3x2 TransformMatrix { get; }
public Transform2D(Vector2 position)
{
Position = position;
Rotation = 0;
Scale = Vector2.One;
TransformMatrix = CreateTransformMatrix(Position, Rotation, Scale);
}
public Transform2D(Vector2 position, float rotation)
{
Position = position;
Rotation = rotation;
Scale = Vector2.One;
TransformMatrix = CreateTransformMatrix(Position, Rotation, Scale);
}
public Transform2D(Vector2 position, float rotation, Vector2 scale)
{
Position = position;
Rotation = rotation;
Scale = scale;
TransformMatrix = CreateTransformMatrix(Position, Rotation, Scale);
}
public Transform2D Compose(Transform2D other)
{
return new Transform2D(Position + other.Position, Rotation + other.Rotation, Scale * other.Scale);
}
private static Matrix3x2 CreateTransformMatrix(Vector2 position, float rotation, Vector2 scale)
{
return
Matrix3x2.CreateScale(scale) *
Matrix3x2.CreateRotation(rotation) *
Matrix3x2.CreateTranslation(position);
}
public bool Equals(Transform2D other)
{
return
Position == other.Position &&
Rotation == other.Rotation &&
Scale == other.Scale;
}
public override bool Equals(System.Object other)
{
if (other is Transform2D otherTransform)
{
return Equals(otherTransform);
}
return false;
}
public override int GetHashCode()
{
return System.HashCode.Combine(Position, Rotation, Scale);
}
public static bool operator ==(Transform2D a, Transform2D b)
{
return a.Equals(b);
}
public static bool operator !=(Transform2D a, Transform2D b)
{
return !a.Equals(b);
}
}
}

17
src/Math/Vector2.cs
View File

@ -878,10 +878,10 @@ namespace MoonWorks.Math
} }
/// <summary> /// <summary>
/// Creates a new <see cref="Vector2"/> that contains a transformation of 2d-vector by the specified <see cref="Matrix4x4"/>. /// Creates a new <see cref="Vector2"/> that contains a transformation of 2d-vector by the specified <see cref="Matrix3x2"/>.
/// </summary> /// </summary>
/// <param name="position">Source <see cref="Vector2"/>.</param> /// <param name="position">Source <see cref="Vector2"/>.</param>
/// <param name="matrix">The transformation <see cref="Matrix4x4"/>.</param> /// <param name="matrix">The transformation <see cref="Matrix3x2"/>.</param>
/// <returns>Transformed <see cref="Vector2"/>.</returns> /// <returns>Transformed <see cref="Vector2"/>.</returns>
public static Vector2 Transform(Vector2 position, Matrix3x2 matrix) public static Vector2 Transform(Vector2 position, Matrix3x2 matrix)
{ {
@ -999,6 +999,19 @@ namespace MoonWorks.Math
); );
} }
/// <summary>
/// Creates a new <see cref="Vector2"/> that contains a transformation of the specified normal by the specified <see cref="Matrix3x2"/>.
/// </summary>
/// <param name="normal">Source <see cref="Vector2"/> which represents a normal vector.</param>
/// <param name="matrix">The transformation <see cref="Matrix3x2"/>.</param>
/// <returns>Transformed normal.</returns>
public static Vector2 TransformNormal(Vector2 normal, Matrix3x2 matrix)
{
return new Vector2(
normal.X * matrix.M11 + normal.Y * matrix.M21,
normal.X * matrix.M12 + normal.Y * matrix.M22);
}
/// <summary> /// <summary>
/// Creates a new <see cref="Vector2"/> that contains a transformation of the specified normal by the specified <see cref="Matrix4x4"/>. /// Creates a new <see cref="Vector2"/> that contains a transformation of the specified normal by the specified <see cref="Matrix4x4"/>.
/// </summary> /// </summary>