Svart hål

tests/Universe.Tests/BlackHoleTests.cs

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+using Universe.App.Runtime;
+using Universe.Core.Generation;
+using Universe.Core.Math;
+using Universe.Core.World;
+
+namespace Universe.Tests;
+
+public sealed class BlackHoleTests
+{
+    [Fact]
+    public void ReplacementIsDeterministicAndPlanetsClearTheDisk()
+    {
+        var generator = new UniverseGenerator(123, blackHoles: new() { OccurrenceChance = 1 });
+        var first = generator.Generate(new(-2, 1, 3));
+        var second = generator.Generate(first.Coordinate);
+        var hole = Assert.Single(first.Stars);
+        Assert.True(hole.IsBlackHole);
+        Assert.Equal(hole, Assert.Single(second.Stars));
+        Assert.Equal(hole.RadiusMeters, hole.BlackHole!.HorizonRadiusMeters);
+        Assert.All(first.Planets, p => Assert.True((p.PositionMeters - hole.PositionMeters).Length >
+            hole.RadiusMeters * hole.BlackHole.DiskOuterRadiusInHorizons));
+    }
+
+    [Fact]
+    public void NearestSearchMatchesWideExhaustiveSearchAndFlightReachesTheHole()
+    {
+        var generator = new UniverseGenerator(0x554E495645525345UL);
+        var streamer = new UniverseStreamer(generator);
+        var start = UniversePosition.AtCellCenter(new(0, 0, 0), generator.CellSizeMeters);
+        var found = streamer.FindNearestBlackHole(start);
+        Assert.True(found.HasValue);
+        var target = found!.Value;
+        var exhaustive = generator.GenerateNeighborhood(start.Sector, 3)
+            .SelectMany(s => s.Stars.Where(h => h.IsBlackHole).Select(h => (System: s, Hole: h)))
+            .MinBy(b => UniversePosition.AtCellCenter(b.System.Coordinate, generator.CellSizeMeters)
+                .Add(b.Hole.PositionMeters, generator.CellSizeMeters).RelativeTo(start, generator.CellSizeMeters).Length);
+        Assert.Equal(exhaustive.Hole.Id, target.Hole.Id);
+        var neighborhood = streamer.Load(start.Sector);
+        var groundPlanet = neighborhood.ActiveSystem.Planets[0];
+        var groundBody = start.Add(groundPlanet.PositionMeters, generator.CellSizeMeters);
+        var groundRadial = new DVector3(1, .3, -.2).Normalized();
+        var groundPosition = groundBody.Add(groundRadial * (TerrainHeight.Sample(groundPlanet, groundRadial) + 1.8), generator.CellSizeMeters);
+        var camera = new FlyCamera(groundPosition, generator.CellSizeMeters);
+        camera.RequestBlackHoleView(target.System, target.Hole, neighborhood.NearbySystems.Append(neighborhood.ActiveSystem));
+        for (var i = 0; i < 650; i++)
+        {
+            camera.Update(1d / 60, DVector3.Zero, neighborhood);
+            if (camera.Position.Sector != neighborhood.ActiveSystem.Coordinate) neighborhood = streamer.Load(camera.Position.Sector);
+        }
+        var body = UniversePosition.AtCellCenter(target.System.Coordinate, generator.CellSizeMeters)
+            .Add(target.Hole.PositionMeters, generator.CellSizeMeters);
+        var relative = body.RelativeTo(camera.Position, generator.CellSizeMeters);
+        Assert.False(camera.IsFocusing);
+        Assert.InRange(relative.Length / target.Hole.RadiusMeters, 25.99, 26.01);
+        Assert.InRange(DVector3.Dot(relative.Normalized(), camera.Forward), .999, 1.001);
+    }
+
+    [Fact]
+    public void ZeroChanceDisablesGenerationAndSearch()
+    {
+        var generator = new UniverseGenerator(123, blackHoles: new() { OccurrenceChance = 0 });
+        Assert.All(generator.GenerateNeighborhood(new()), s => Assert.All(s.Stars, h => Assert.False(h.IsBlackHole)));
+        Assert.Null(new UniverseStreamer(generator).FindNearestBlackHole(UniversePosition.AtCellCenter(new(), generator.CellSizeMeters)));
+    }
+}