102 lines
3.2 KiB
C#
102 lines
3.2 KiB
C#
using Microsoft.Xna.Framework;
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using Xunit;
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namespace MrGameEng.Pathfinding.Tests;
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public class FlowFieldTests
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{
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[Fact]
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public void Build_DistancesGrowFromGoal_DirectionsDescend()
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{
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var grid = new TestGrid(".....", ".###.", ".....");
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var builder = new FlowFieldBuilder(grid);
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var field = new FlowField();
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builder.Build([new Point(0, 0)], field);
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Assert.Equal(0f, field.DistanceAt(0, 0));
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Assert.True(field.DistanceAt(4, 2) > field.DistanceAt(1, 0));
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// Из любой достижимой не-целевой клетки направление ведёт к клетке с меньшей дистанцией.
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for (var y = 0; y < grid.Height; y++)
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{
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for (var x = 0; x < grid.Width; x++)
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{
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if (
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!grid.IsPassable(x, y)
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|| !field.IsReachable(x, y)
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|| field.DistanceAt(x, y) == 0f
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)
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{
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continue;
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}
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var direction = field.DirectionAt(x, y);
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Assert.NotEqual(Vector2.Zero, direction);
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var nx = x + Math.Sign(MathF.Round(direction.X * 10f));
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var ny = y + Math.Sign(MathF.Round(direction.Y * 10f));
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Assert.True(
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field.DistanceAt(nx, ny) < field.DistanceAt(x, y),
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$"direction at ({x},{y}) does not descend"
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);
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}
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}
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}
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[Fact]
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public void Build_UnreachablePocket_IsFlagged()
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{
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var grid = new TestGrid("..#..", "..#..", "..#..");
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var builder = new FlowFieldBuilder(grid);
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var field = new FlowField();
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builder.Build([new Point(0, 1)], field);
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Assert.False(field.IsReachable(4, 1));
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Assert.Equal(Vector2.Zero, field.DirectionAt(4, 1));
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Assert.True(field.IsReachable(1, 2));
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}
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[Fact]
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public void Build_MultipleGoals_EachCellFlowsToNearest()
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{
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var grid = new TestGrid("..........");
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var builder = new FlowFieldBuilder(grid);
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var field = new FlowField();
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builder.Build([new Point(0, 0), new Point(9, 0)], field);
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Assert.True(field.DirectionAt(2, 0).X < 0f); // ближе к левой цели
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Assert.True(field.DirectionAt(7, 0).X > 0f); // ближе к правой
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Assert.Equal(0f, field.DistanceAt(9, 0));
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}
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[Fact]
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public void Build_Rebuild_OverwritesPreviousField()
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{
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var grid = new TestGrid(".....");
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var builder = new FlowFieldBuilder(grid);
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var field = new FlowField();
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builder.Build([new Point(0, 0)], field);
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Assert.True(field.DirectionAt(4, 0).X < 0f);
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builder.Build([new Point(4, 0)], field);
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Assert.True(field.DirectionAt(0, 0).X > 0f);
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Assert.Equal(0f, field.DistanceAt(4, 0));
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}
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[Fact]
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public void Build_NoValidGoals_EverythingUnreachable()
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{
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var grid = new TestGrid(".#.");
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var builder = new FlowFieldBuilder(grid);
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var field = new FlowField();
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builder.Build([new Point(1, 0)], field); // цель — стена
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Assert.False(field.IsReachable(0, 0));
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Assert.False(field.IsReachable(2, 0));
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}
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}
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