This commit is contained in:
Syntriax 2023-12-07 10:55:49 +03:00
parent 0fd1ebe726
commit 6183d2225f
9 changed files with 276 additions and 185 deletions

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@ -6,6 +6,7 @@ using Microsoft.Xna.Framework;
using Syntriax.Engine.Core;
using Syntriax.Engine.Core.Abstract;
using Syntriax.Engine.Physics2D.Abstract;
using Syntriax.Engine.Physics2D.Primitives;
namespace Syntriax.Engine.Physics2D;
@ -38,7 +39,7 @@ public class Collider2DAABBBehaviour : BehaviourOverride, ICollider2D
public bool CheckCollision(Vector2 point)
{
return AABBWorld.Inside(point);
return AABBWorld.Overlaps(point);
}
public void Recalculate()

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@ -5,6 +5,7 @@ using Microsoft.Xna.Framework;
using Syntriax.Engine.Core.Abstract;
using Syntriax.Engine.Physics2D.Abstract;
using Syntriax.Engine.Physics2D.Primitives;
namespace Syntriax.Engine.Physics2D;

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@ -1,76 +1,18 @@
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using Microsoft.Xna.Framework;
using Syntriax.Engine.Physics2D.Primitives;
namespace Syntriax.Engine.Physics2D;
public record Line(Vector2 From, Vector2 To)
{
public Vector2 Direction => Vector2.Normalize(To - From);
public float Length => (From - To).Length();
public float LengthSquared => (From - To).LengthSquared();
}
public record LineEquation(float Slope, float OffsetY);
public record Triangle(Vector2 A, Vector2 B, Vector2 C);
public record Circle(Vector2 Position, float Radius);
public record AABB(Vector2 LowerBoundary, Vector2 UpperBoundary);
public static class PhysicsMath
{
public static Vector2 Scale(this Vector2 original, Vector2 scale)
=> new Vector2(original.X * scale.X, original.Y * scale.Y);
public static Vector2 ClosestPointTo(this Line line, Vector2 point)
{
// Convert edge points to vectors
var edgeVector = new Vector2(line.To.X - line.From.X, line.To.Y - line.From.Y);
var pointVector = new Vector2(point.X - line.From.X, point.Y - line.From.Y);
// Calculate the projection of pointVector onto edgeVector
float t = (pointVector.X * edgeVector.X + pointVector.Y * edgeVector.Y) / (edgeVector.X * edgeVector.X + edgeVector.Y * edgeVector.Y);
// Clamp t to the range [0, 1] to ensure the closest point is on the edge
t = Math.Max(0, Math.Min(1, t));
// Calculate the closest point on the edge
float closestX = line.From.X + t * edgeVector.X;
float closestY = line.From.Y + t * edgeVector.Y;
return new Vector2((float)closestX, (float)closestY);
}
public static float GetArea(this Triangle triangle)
{
return Math.Abs((triangle.A.X * (triangle.B.Y - triangle.C.Y) +
triangle.B.X * (triangle.C.Y - triangle.A.Y) +
triangle.C.X * (triangle.A.Y - triangle.B.Y)) * .5f);
}
public static Circle ToCircumCircle(this Triangle triangle)
{
Vector2 midAB = (triangle.A + triangle.B) / 2;
Vector2 midBC = (triangle.B + triangle.C) / 2;
float slopeAB = (triangle.B.Y - triangle.A.Y) / (triangle.B.X - triangle.A.X);
float slopeBC = (triangle.C.Y - triangle.B.Y) / (triangle.C.X - triangle.B.X);
Vector2 center;
if (Math.Abs(slopeAB - slopeBC) > float.Epsilon)
{
float x = (slopeAB * slopeBC * (triangle.A.Y - triangle.C.Y) + slopeBC * (triangle.A.X + triangle.B.X) - slopeAB * (triangle.B.X + triangle.C.X)) / (2 * (slopeBC - slopeAB));
float y = -(x - (triangle.A.X + triangle.B.X) / 2) / slopeAB + (triangle.A.Y + triangle.B.Y) / 2;
center = new Vector2((float)x, (float)y);
}
else
center = (midAB + midBC) * .5f;
return new(center, Vector2.Distance(center, triangle.A));
}
public static Triangle ToSuperTriangle(IList<Vector2> vertices)
public static Triangle ToSuperTriangle(this IList<Vector2> vertices)
{
float minX = float.MaxValue, minY = float.MaxValue;
float maxX = float.MinValue, maxY = float.MinValue;
@ -111,35 +53,9 @@ public static class PhysicsMath
lines.Add(new(vertices[^1], vertices[0]));
}
public static bool ExistIn(Line lineToCheck, List<Vector2> vertices)
{
for (int i = 0; i < vertices.Count - 1; i++)
{
Vector2 vertexCurrent = vertices[i];
Vector2 vertexNext = vertices[i];
if (lineToCheck.From == vertexCurrent && lineToCheck.To == vertexNext) return true;
if (lineToCheck.From == vertexNext && lineToCheck.To == vertexCurrent) return true;
}
Vector2 vertexFirst = vertices[0];
Vector2 vertexLast = vertices[^1];
if (lineToCheck.From == vertexFirst && lineToCheck.To == vertexLast) return true;
if (lineToCheck.From == vertexLast && lineToCheck.To == vertexFirst) return true;
return false;
}
public static bool LaysOn(this Vector2 point, Line line)
=> ApproximatelyEqualEpsilon(line.Resolve(point.X), point, float.Epsilon);
=> line.Resolve(point.X).ApproximatelyEquals(point);
public static LineEquation ToLineEquation(this Line line)
{
Vector2 slopeVector = line.To - line.From;
float slope = slopeVector.Y / slopeVector.X;
float yOffset = line.From.Y - (slope * line.From.X);
return new LineEquation(slope, yOffset);
}
// Given three collinear points p, q, r, the function checks if
// point q lies on line segment 'pr'
@ -173,98 +89,10 @@ public static class PhysicsMath
=> ((q0.X - p0.X) * (p1.Y - p0.Y) - (q0.Y - p0.Y) * (p1.X - p0.X)) /
((q1.Y - q0.Y) * (p1.X - p0.X) - (q1.X - q0.X) * (p1.Y - p0.Y));
public static float IntersectionParameterT(this Line l0, Line l1)
=> ((l1.From.X - l0.From.X) * (l0.To.Y - l0.From.Y) - (l1.From.Y - l0.From.Y) * (l0.To.X - l0.From.X)) /
((l1.To.Y - l1.From.Y) * (l0.To.X - l0.From.X) - (l1.To.X - l1.From.X) * (l0.To.Y - l0.From.Y));
public static float GetT(this Line line, Vector2 point)
{
// if (!point.LaysOn(line))
// throw new Exception("Point does not lay on Line");
float fromX = MathF.Abs(line.From.X);
float toX = MathF.Abs(line.To.X);
float pointX = MathF.Abs(point.X);
float min = MathF.Min(fromX, toX);
float max = MathF.Max(fromX, toX) - min;
pointX -= min;
return pointX / max;
}
public static Vector2 Resolve(this Line line, float x)
{
LineEquation lineEquation = line.ToLineEquation();
// y = mx + b
float y = lineEquation.Slope * x + lineEquation.OffsetY;
return new Vector2(x, y);
}
public static Vector2 IntersectionPoint(this Line l1, Line l2)
=> Vector2.Lerp(l1.From, l1.To, IntersectionParameterT(l1, l2));
public static bool Intersects(this Line l1, Line l2)
{
int o1 = Orientation(l1.From, l1.To, l2.From);
int o2 = Orientation(l1.From, l1.To, l2.To);
int o3 = Orientation(l2.From, l2.To, l1.From);
int o4 = Orientation(l2.From, l2.To, l1.To);
if (o1 != o2 && o3 != o4)
return true;
if (o1 == 0 && OnSegment(l1.From, l2.From, l1.To)) return true;
if (o2 == 0 && OnSegment(l1.From, l2.To, l1.To)) return true;
if (o3 == 0 && OnSegment(l2.From, l1.From, l2.To)) return true;
if (o4 == 0 && OnSegment(l2.From, l1.To, l2.To)) return true;
return false;
}
public static bool Intersects(this Line l1, Line l2, [NotNullWhen(returnValue: true)] out Vector2? point)
{
point = null;
bool result = Intersects(l1, l2);
if (result)
point = IntersectionPoint(l1, l2);
return result;
}
public static bool Intersects(this Circle circle, Circle circleOther)
{
float distanceSquared = (circle.Position - circleOther.Position).LengthSquared();
float radiusSumSquared = circle.Radius * circle.Radius + circleOther.Radius * circleOther.Radius;
return distanceSquared < radiusSumSquared;
}
public static bool Inside(this Triangle triangle, Vector2 point)
{
float originalTriangleArea = GetArea(triangle);
float pointTriangleArea1 = GetArea(new Triangle(point, triangle.B, triangle.C));
float pointTriangleArea2 = GetArea(new Triangle(triangle.A, point, triangle.C));
float pointTriangleArea3 = GetArea(new Triangle(triangle.A, triangle.B, point));
float pointTriangleAreasSum = pointTriangleArea1 + pointTriangleArea2 + pointTriangleArea3;
return originalTriangleArea >= pointTriangleAreasSum;
}
public static bool Inside(this AABB aabb, Vector2 point)
=> point.X >= aabb.LowerBoundary.X && point.X <= aabb.UpperBoundary.X &&
point.Y >= aabb.LowerBoundary.Y && point.Y <= aabb.UpperBoundary.Y;
public static bool Inside(this Circle circle, Vector2 point)
=> (circle.Position - point).LengthSquared() <= circle.Radius * circle.Radius;
public static bool ApproximatelyEqualEpsilon(float a, float b, float epsilon)
public static bool ApproximatelyEquals(this float a, float b)
=> ApproximatelyEqualsEpsilon(a, b, float.Epsilon);
public static bool ApproximatelyEqualsEpsilon(this float a, float b, float epsilon)
{
if (a == b)
return true;
@ -277,10 +105,11 @@ public static class PhysicsMath
if (a == 0.0f || b == 0.0f || diff < floatNormal)
return diff < (epsilon * floatNormal);
return diff / Math.Min((absA + absB), float.MaxValue) < epsilon;
}
public static bool ApproximatelyEqualEpsilon(Vector2 a, Vector2 b, float epsilon)
{
return ApproximatelyEqualEpsilon(a.X, b.X, epsilon) && ApproximatelyEqualEpsilon(a.Y, b.Y, epsilon);
return diff / Math.Min(absA + absB, float.MaxValue) < epsilon;
}
public static bool ApproximatelyEquals(this Vector2 a, Vector2 b)
=> ApproximatelyEqualEpsilon(a, b, float.Epsilon);
public static bool ApproximatelyEqualEpsilon(this Vector2 a, Vector2 b, float epsilon)
=> ApproximatelyEqualsEpsilon(a.X, b.X, epsilon) && ApproximatelyEqualsEpsilon(a.Y, b.Y, epsilon);
}

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@ -0,0 +1,10 @@
using Microsoft.Xna.Framework;
namespace Syntriax.Engine.Physics2D.Primitives;
public record AABB(Vector2 LowerBoundary, Vector2 UpperBoundary)
{
public bool Overlaps(Vector2 point)
=> point.X >= LowerBoundary.X && point.X <= UpperBoundary.X &&
point.Y >= LowerBoundary.Y && point.Y <= UpperBoundary.Y;
}

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@ -0,0 +1,16 @@
using Microsoft.Xna.Framework;
namespace Syntriax.Engine.Physics2D.Primitives;
public record Circle(Vector2 Position, float Radius)
{
public bool Intersects(Circle circleOther)
{
float distanceSquared = (Position - circleOther.Position).LengthSquared();
float radiusSumSquared = Radius * Radius + circleOther.Radius * circleOther.Radius;
return distanceSquared < radiusSumSquared;
}
public bool Overlaps(Vector2 point) => (Position - point).LengthSquared() <= Radius * Radius;
}

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@ -0,0 +1,121 @@
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using Microsoft.Xna.Framework;
namespace Syntriax.Engine.Physics2D.Primitives;
public record Line(Vector2 From, Vector2 To)
{
public Vector2 Direction => Vector2.Normalize(To - From);
public float Length => (From - To).Length();
public float LengthSquared => (From - To).LengthSquared();
public LineEquation LineEquation
{
get
{
Vector2 slopeVector = To - From;
float slope = slopeVector.Y / slopeVector.X;
float yOffset = From.Y - (slope * From.X);
return new LineEquation(slope, yOffset);
}
}
public bool Intersects(Vector2 point)
=> Resolve(point.X).ApproximatelyEquals(point);
public float GetT(Vector2 point)
{
float fromX = MathF.Abs(From.X);
float toX = MathF.Abs(To.X);
float pointX = MathF.Abs(point.X);
float min = MathF.Min(fromX, toX);
float max = MathF.Max(fromX, toX) - min;
pointX -= min;
return pointX / max;
}
public bool Exist(List<Vector2> vertices)
{
for (int i = 0; i < vertices.Count - 1; i++)
{
Vector2 vertexCurrent = vertices[i];
Vector2 vertexNext = vertices[i];
if (From == vertexCurrent && To == vertexNext) return true;
if (From == vertexNext && To == vertexCurrent) return true;
}
Vector2 vertexFirst = vertices[0];
Vector2 vertexLast = vertices[^1];
if (From == vertexFirst && To == vertexLast) return true;
if (From == vertexLast && To == vertexFirst) return true;
return false;
}
public float IntersectionParameterT(Line other)
=> ((other.From.X - From.X) * (To.Y - From.Y) - (other.From.Y - From.Y) * (To.X - From.X)) /
((other.To.Y - other.From.Y) * (To.X - From.X) - (other.To.X - other.From.X) * (To.Y - From.Y));
public Vector2 Resolve(float x)
=> new Vector2(x, LineEquation.Resolve(x));
public Vector2 ClosestPointTo(Vector2 point)
{
// Convert edge points to vectors
var edgeVector = new Vector2(To.X - From.X, To.Y - From.Y);
var pointVector = new Vector2(point.X - From.X, point.Y - From.Y);
// Calculate the projection of pointVector onto edgeVector
float t = (pointVector.X * edgeVector.X + pointVector.Y * edgeVector.Y) / (edgeVector.X * edgeVector.X + edgeVector.Y * edgeVector.Y);
// Clamp t to the range [0, 1] to ensure the closest point is on the edge
t = Math.Max(0, Math.Min(1, t));
// Calculate the closest point on the edge
float closestX = From.X + t * edgeVector.X;
float closestY = From.Y + t * edgeVector.Y;
return new Vector2((float)closestX, (float)closestY);
}
public Vector2 IntersectionPoint(Line other)
=> Vector2.Lerp(From, To, IntersectionParameterT(other));
public bool Intersects(Line other)
{
int o1 = PhysicsMath.Orientation(From, To, other.From);
int o2 = PhysicsMath.Orientation(From, To, other.To);
int o3 = PhysicsMath.Orientation(other.From, other.To, From);
int o4 = PhysicsMath.Orientation(other.From, other.To, To);
if (o1 != o2 && o3 != o4)
return true;
if (o1 == 0 && PhysicsMath.OnSegment(From, other.From, To)) return true;
if (o2 == 0 && PhysicsMath.OnSegment(From, other.To, To)) return true;
if (o3 == 0 && PhysicsMath.OnSegment(other.From, From, other.To)) return true;
if (o4 == 0 && PhysicsMath.OnSegment(other.From, To, other.To)) return true;
return false;
}
public bool Intersects(Line other, [NotNullWhen(returnValue: true)] out Vector2? point)
{
point = null;
bool result = Intersects(other);
if (result)
point = IntersectionPoint(other);
return result;
}
}

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@ -0,0 +1,6 @@
namespace Syntriax.Engine.Physics2D.Primitives;
public record LineEquation(float Slope, float OffsetY)
{
public float Resolve(float x) => Slope * x + OffsetY; // y = mx + b
}

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@ -0,0 +1,56 @@
using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
namespace Syntriax.Engine.Physics2D.Primitives;
public record Shape(IList<Vector2> Vertices)
{
public Triangle SuperTriangle
{
get
{
float minX = float.MaxValue, minY = float.MaxValue;
float maxX = float.MinValue, maxY = float.MinValue;
foreach (Vector2 point in Vertices)
{
minX = Math.Min(minX, point.X);
minY = Math.Min(minY, point.Y);
maxX = Math.Max(maxX, point.X);
maxY = Math.Max(maxY, point.Y);
}
float dx = maxX - minX;
float dy = maxY - minY;
float deltaMax = Math.Max(dx, dy);
float midX = (minX + maxX) / 2;
float midY = (minY + maxY) / 2;
Vector2 p1 = new Vector2((float)midX - 20f * (float)deltaMax, (float)midY - (float)deltaMax);
Vector2 p2 = new Vector2((float)midX, (float)midY + 20 * (float)deltaMax);
Vector2 p3 = new Vector2((float)midX + 20 * (float)deltaMax, (float)midY - (float)deltaMax);
return new Triangle(p1, p2, p3);
}
}
public IList<Line> Lines
{
get
{
List<Line> lines = new List<Line>(Vertices.Count - 1);
GetLinesNonAlloc(lines);
return lines;
}
}
public void GetLinesNonAlloc(IList<Line> lines)
{
lines.Clear();
for (int i = 0; i < Vertices.Count - 1; i++)
lines.Add(new(Vertices[i], Vertices[i + 1]));
lines.Add(new(Vertices[^1], Vertices[0]));
}
}

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@ -0,0 +1,51 @@
using System;
using Microsoft.Xna.Framework;
namespace Syntriax.Engine.Physics2D.Primitives;
public record Triangle(Vector2 A, Vector2 B, Vector2 C)
{
public float Area => Math.Abs((
A.X * (B.Y - C.Y) +
B.X * (C.Y - A.Y) +
C.X * (A.Y - B.Y)
) * .5f);
public Circle CircumCircle
{
get
{
Vector2 midAB = (A + B) / 2;
Vector2 midBC = (B + C) / 2;
float slopeAB = (B.Y - A.Y) / (B.X - A.X);
float slopeBC = (C.Y - B.Y) / (C.X - B.X);
Vector2 center;
if (Math.Abs(slopeAB - slopeBC) > float.Epsilon)
{
float x = (slopeAB * slopeBC * (A.Y - C.Y) + slopeBC * (A.X + B.X) - slopeAB * (B.X + C.X)) / (2 * (slopeBC - slopeAB));
float y = -(x - (A.X + B.X) / 2) / slopeAB + (A.Y + B.Y) / 2;
center = new Vector2((float)x, (float)y);
}
else
center = (midAB + midBC) * .5f;
return new(center, Vector2.Distance(center, A));
}
}
public bool Overlaps(Vector2 point)
{
float originalTriangleArea = Area;
float pointTriangleArea1 = new Triangle(point, B, C).Area;
float pointTriangleArea2 = new Triangle(A, point, C).Area;
float pointTriangleArea3 = new Triangle(A, B, point).Area;
float pointTriangleAreasSum = pointTriangleArea1 + pointTriangleArea2 + pointTriangleArea3;
return originalTriangleArea >= pointTriangleAreasSum;
}
}