45 lines
1.6 KiB
C#
45 lines
1.6 KiB
C#
using System;
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using Syntriax.Engine.Core;
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namespace Syntriax.Engine.Physics2D.Primitives;
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public record Triangle(Vector2D A, Vector2D B, Vector2D C)
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{
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public float Area
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=> .5f * MathF.Abs(
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A.X * (B.Y - C.Y) +
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B.X * (C.Y - A.Y) +
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C.X * (A.Y - B.Y)
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);
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public static Circle GetCircumCircle(Triangle triangle)
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{
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Vector2D midAB = (triangle.A + triangle.B) / 2f;
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Vector2D midBC = (triangle.B + triangle.C) / 2f;
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float slopeAB = (triangle.B.Y - triangle.A.Y) / (triangle.B.X - triangle.A.X);
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float slopeBC = (triangle.C.Y - triangle.B.Y) / (triangle.C.X - triangle.B.X);
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Vector2D center;
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if (MathF.Abs(slopeAB - slopeBC) > float.Epsilon)
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{
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float x = (slopeAB * slopeBC * (triangle.A.Y - triangle.C.Y) + slopeBC * (triangle.A.X + triangle.B.X) - slopeAB * (triangle.B.X + triangle.C.X)) / (2f * (slopeBC - slopeAB));
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float y = -(x - (triangle.A.X + triangle.B.X) / 2f) / slopeAB + (triangle.A.Y + triangle.B.Y) / 2f;
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center = new Vector2D(x, y);
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}
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else
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center = (midAB + midBC) * .5f;
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return new(center, Vector2D.Distance(center, triangle.A));
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}
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public static bool ApproximatelyEquals(Triangle left, Triangle right)
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=> left.A.ApproximatelyEquals(right.A) && left.B.ApproximatelyEquals(right.B) && left.C.ApproximatelyEquals(right.C);
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}
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public static class TriangleExtensions
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{
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public static bool ApproximatelyEquals(this Triangle left, Triangle right) => Triangle.ApproximatelyEquals(left, right);
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}
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