s&box

Utility/MeshUtility.cs

Utility static class with helpers for building PolygonMesh geometry. It adds or reuses vertices, creates textured quads and triangles, assigns materials and UVs, and checks for duplicate vertex handles.

Native Interop

using System.Collections.Generic;
using Sandbox;

namespace RedSnail.RoadTool;

public static class MeshUtility
{
	public static HalfEdgeMesh.VertexHandle GetOrAddVertex(PolygonMesh _Mesh, Dictionary<Vector3, HalfEdgeMesh.VertexHandle> _Cache, Vector3 _Pos)
	{
		if (!_Cache.TryGetValue(_Pos, out var handle))
		{
			handle = _Mesh.AddVertices(_Pos)[0];
			_Cache[_Pos] = handle;
		}

		return handle;
	}



	public static void AddTexturedQuad(PolygonMesh _Mesh, Material _Material,
		HalfEdgeMesh.VertexHandle _A, HalfEdgeMesh.VertexHandle _B,
		HalfEdgeMesh.VertexHandle _C, HalfEdgeMesh.VertexHandle _D,
		Vector2 _UvA, Vector2 _UvB, Vector2 _UvC, Vector2 _UvD)
	{
		if (HasDuplicateVertex(_A, _B, _C, _D))
			return;

		var face = _Mesh.AddFace(_A, _B, _C, _D);

		if (!face.IsValid)
			return;

		_Mesh.SetFaceMaterial(face, _Material);
		_Mesh.SetFaceTextureCoords(face, new List<Vector2> { _UvA, _UvB, _UvC, _UvD });
	}



	public static void AddTexturedTriangle(PolygonMesh _Mesh, Material _Material,
		HalfEdgeMesh.VertexHandle _A, HalfEdgeMesh.VertexHandle _B,
		HalfEdgeMesh.VertexHandle _C,
		Vector2 _UvA, Vector2 _UvB, Vector2 _UvC)
	{
		if (HasDuplicateVertex(_A, _B, _C))
			return;

		var face = _Mesh.AddFace(_A, _B, _C);

		if (!face.IsValid)
			return;

		_Mesh.SetFaceMaterial(face, _Material);
		_Mesh.SetFaceTextureCoords(face, new List<Vector2> { _UvA, _UvB, _UvC });
	}



	private static bool HasDuplicateVertex(HalfEdgeMesh.VertexHandle _A, HalfEdgeMesh.VertexHandle _B, HalfEdgeMesh.VertexHandle _C)
	{
		return _A.Equals(_B) || _A.Equals(_C) || _B.Equals(_C);
	}



	private static bool HasDuplicateVertex(HalfEdgeMesh.VertexHandle _A, HalfEdgeMesh.VertexHandle _B, HalfEdgeMesh.VertexHandle _C, HalfEdgeMesh.VertexHandle _D)
	{
		return _A.Equals(_B) || _A.Equals(_C) || _A.Equals(_D) ||
			_B.Equals(_C) || _B.Equals(_D) ||
			_C.Equals(_D);
	}
}