Unity UGUI 程序化网格 09：方向与夹角生成扇形瞄准

// Assets/OnPopulateMeshBook/Chapters/Chapter09_Sector/
// Runtime/SectorGraphic.cs · 完整组件上半部
using UnityEngine;
using UnityEngine.UI;

namespace OnPopulateMeshBook.Chapter09
{
    public sealed class SectorGraphic : Graphic
    {
        [SerializeField, Min(0f)] private float innerRadius;
        [SerializeField, Min(0f)] private float outerRadius = 100f;
        [SerializeField] private float startAngle = -30f;
        [SerializeField, Range(0f, 360f)]
        private float sweepAngle = 60f;
        [SerializeField, Min(3)]
        private int fullCircleSegments = 48;

        public float InnerRadius { get => innerRadius;
            set { innerRadius = Mathf.Max(0f, value); SetVerticesDirty(); } }
        public float OuterRadius { get => outerRadius;
            set { outerRadius = Mathf.Max(0f, value); SetVerticesDirty(); } }
        public float StartAngle { get => startAngle;
            set { startAngle = value; SetVerticesDirty(); } }
        public float SweepAngle { get => sweepAngle;
            set { sweepAngle = Mathf.Clamp(value, 0f, 360f);
                SetVerticesDirty(); } }
        public int FullCircleSegments { get => fullCircleSegments;
            set { fullCircleSegments = Mathf.Max(3, value);
                SetVerticesDirty(); } }

        public int StepCount => sweepAngle <= 0f
            ? 0
            : Mathf.Max(1, Mathf.CeilToInt(
                Mathf.Max(3, fullCircleSegments) *
                sweepAngle / 360f));

        protected override void OnPopulateMesh(VertexHelper vh)
        {
            vh.Clear();
            var inner = Mathf.Clamp(innerRadius, 0f, outerRadius);
            var steps = StepCount;
            if (outerRadius <= 0f ||
                inner >= outerRadius || steps == 0) return;

            if (inner <= 0f) PopulateFan(vh, steps);
            else PopulateBand(vh, inner, steps);
        }

{
  "fixedInput": "direction=90 sweep=60 radius=140 fullSegments=36",
  "derived": {"start":60, "end":120, "steps":6},
  "component": "SectorGraphic",
  "vertexCount": 8,
  "indexCount": 18,
  "selectedVertices": [
    {"index":0, "position":[0.0,0.0,0.0]},
    {"index":1, "position":[69.999992,121.243561,0.0]},
    {"index":4, "position":[-0.000006,140.0,0.0]},
    {"index":7, "position":[-70.000008,121.243553,0.0]}
  ],
  "indices": [0,1,2, 0,2,3, 0,3,4,
              0,4,5, 0,5,6, 0,6,7]
}

// SectorGraphic.cs · 完整组件下半部
        private void PopulateFan(VertexHelper vh, int steps)
        {
            AddVertex(vh, Vector2.zero);
            for (var i = 0; i <= steps; i++)
                AddVertex(vh, PointOnArc(outerRadius, i, steps));
            for (var i = 0; i < steps; i++)
                vh.AddTriangle(0, i + 1, i + 2);
        }

        private void PopulateBand(
            VertexHelper vh, float inner, int steps)
        {
            for (var i = 0; i <= steps; i++)
            {
                AddVertex(vh, PointOnArc(inner, i, steps));
                AddVertex(vh, PointOnArc(outerRadius, i, steps));
            }
            for (var i = 0; i < steps; i++)
            {
                var start = i * 2;
                vh.AddTriangle(start, start + 1, start + 3);
                vh.AddTriangle(start + 3, start + 2, start);
            }
        }

        private Vector2 PointOnArc(
            float radius, int index, int steps)
        {
            var degrees =
                startAngle + sweepAngle * index / steps;
            var radians = degrees * Mathf.Deg2Rad;
            return new Vector2(
                Mathf.Cos(radians), Mathf.Sin(radians)) * radius;
        }

        private void AddVertex(
            VertexHelper vh, Vector2 position)
        {
            var vertex = UIVertex.simpleVert;
            vertex.position = position;
            vertex.color = color;
            vh.AddVert(vertex);
        }
    }
}

// Assets/OnPopulateMeshBook/Chapters/Chapter09_Sector/
// Tests/Editor/SectorGraphicTests.cs
[Test]
public void Populate_SixtyDegreeFanUsesSixSteps()
{
    var graphic = MeshTestSupport.CreateGraphic<SectorGraphic>(
        new Vector2(220f, 220f));
    graphic.InnerRadius = 0f;
    graphic.OuterRadius = 100f;
    graphic.FullCircleSegments = 36;
    graphic.StartAngle = 60f;
    graphic.SweepAngle = 60f;
    var mesh = MeshTestSupport.Build(graphic);
    Assert.That(graphic.StepCount, Is.EqualTo(6));
    Assert.That(mesh.vertexCount, Is.EqualTo(8));
    Assert.That(mesh.triangles, Has.Length.EqualTo(18));
    MeshTestSupport.AssertFinite(mesh);
    MeshTestSupport.AssertIndicesInRange(mesh);
    MeshTestSupport.Destroy(graphic, mesh);
}

[Test]
public void Populate_ZeroSweepProducesEmptyMesh()
{
    var graphic = MeshTestSupport.CreateGraphic<SectorGraphic>(
        new Vector2(220f, 220f));
    graphic.SweepAngle = 0f;
    var mesh = MeshTestSupport.Build(graphic);
    Assert.That(mesh.vertexCount, Is.Zero);
    MeshTestSupport.Destroy(graphic, mesh);
}

[Test]
public void Populate_FullCircleSegmentsClampToThree()
{
    var graphic = MeshTestSupport.CreateGraphic<SectorGraphic>(
        new Vector2(220f, 220f));
    graphic.OuterRadius = 100f;
    graphic.FullCircleSegments = 1;
    graphic.SweepAngle = 360f;
    var mesh = MeshTestSupport.Build(graphic);
    Assert.That(graphic.FullCircleSegments, Is.EqualTo(3));
    Assert.That(graphic.StepCount, Is.EqualTo(3));
    Assert.That(mesh.vertexCount, Is.EqualTo(5));
    Assert.That(mesh.triangles, Has.Length.EqualTo(9));
    MeshTestSupport.Destroy(graphic, mesh);
}

"$UNITY_EDITOR" \
  -batchmode -nographics \
  -projectPath "$PROJECT_ROOT/.tmp/unity-onpopulate-mesh-lab" \
  -runTests -testPlatform EditMode \
  -testResults "$ARTIFACTS/editmode-results.xml" \
  -logFile "$ARTIFACTS/editmode.log"
echo "process_exit_code=$?"

process_exit_code=0
test-run result=Passed
total=19 passed=19 failed=0 skipped=0
duration=0.0400379s

Populate_FullCircleSegmentsClampToThree
result=Passed duration=0.000730s
segments=3 stepCount=3 vertexCount=5 indexCount=9
Populate_SixtyDegreeFanUsesSixSteps
result=Passed duration=0.000206s
stepCount=6 vertexCount=8 indexCount=18
Populate_ZeroSweepProducesEmptyMesh
result=Passed duration=0.000116s
stepCount=0 vertexCount=0