520589911b
Projects an XY point onto a cell's floor polygons via brute-force triangle iteration + barycentric Z interpolation. Fan-triangulates quads and larger polygons. Returns null when outside all floor surfaces. Accepts pre-transformed world-space vertex positions so the caller handles EnvCell coordinate transforms. Second component of the physics collision engine. 4 new tests, all green. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
90 lines
2.7 KiB
C#
90 lines
2.7 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Numerics;
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using AcDream.Core.Physics;
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using Xunit;
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namespace AcDream.Core.Tests.Physics;
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public class CellSurfaceTests
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{
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/// <summary>
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/// Build a minimal CellSurface representing a flat square floor
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/// centered at (originX, originY) with the given half-size and Z.
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/// The floor polygon is a quad: 4 vertices at the corners.
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/// </summary>
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private static CellSurface MakeFlatFloor(
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uint cellId, float originX, float originY, float z,
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float halfSize = 10f)
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{
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// 4 vertices forming a square floor at the given Z, in WORLD space.
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var vertices = new Dictionary<ushort, Vector3>
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{
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[0] = new(originX - halfSize, originY - halfSize, z),
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[1] = new(originX + halfSize, originY - halfSize, z),
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[2] = new(originX + halfSize, originY + halfSize, z),
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[3] = new(originX - halfSize, originY + halfSize, z),
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};
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// One quad polygon with 4 vertex IDs.
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var polygonVertexIds = new List<List<short>>
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{
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new() { 0, 1, 2, 3 },
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};
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return new CellSurface(cellId, vertices, polygonVertexIds);
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}
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[Fact]
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public void SampleFloorZ_InsideFlat_ReturnsZ()
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{
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var surface = MakeFlatFloor(0x0100, originX: 50f, originY: 50f, z: 10f);
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float? z = surface.SampleFloorZ(50f, 50f);
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Assert.NotNull(z);
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Assert.Equal(10f, z!.Value, precision: 2);
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}
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[Fact]
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public void SampleFloorZ_OutsideFloor_ReturnsNull()
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{
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var surface = MakeFlatFloor(0x0100, originX: 50f, originY: 50f, z: 10f, halfSize: 5f);
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float? z = surface.SampleFloorZ(100f, 100f);
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Assert.Null(z);
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}
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[Fact]
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public void SampleFloorZ_AtEdge_ReturnsZ()
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{
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var surface = MakeFlatFloor(0x0100, originX: 50f, originY: 50f, z: 10f, halfSize: 10f);
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// Right at the edge of the polygon.
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float? z = surface.SampleFloorZ(60f, 50f);
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Assert.NotNull(z);
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Assert.Equal(10f, z!.Value, precision: 2);
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}
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[Fact]
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public void SampleFloorZ_SlopedFloor_InterpolatesZ()
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{
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// A triangular floor that slopes from Z=0 to Z=20.
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var vertices = new Dictionary<ushort, Vector3>
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{
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[0] = new(0f, 0f, 0f),
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[1] = new(20f, 0f, 0f),
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[2] = new(10f, 20f, 20f),
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};
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var polygons = new List<List<short>> { new() { 0, 1, 2 } };
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var surface = new CellSurface(0x0100, vertices, polygons);
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// At the centroid (10, 6.67): Z should be roughly 6.67
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float? z = surface.SampleFloorZ(10f, 6.67f);
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Assert.NotNull(z);
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Assert.InRange(z!.Value, 5f, 8f); // approximate
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}
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}
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