CloseThicknessExample.cs

using System;
using UnityEngine;
using Shapes;
using UnityEditor;
using UnityEngine.Rendering;
using UnityEngine.UIElements;

[ExecuteAlways]
public class CloseThicknessExample : ImmediateModeShapeDrawer {
    [Min(0)]
    public float pixelThickness = 100;

    public Transform pointA;
    public Transform pointB;
    
    public bool volumetric = true;
    public bool flipOrder = false;

    private Color refColor = new Color(1, 1, 1, 0.25f);
    private Color[] Colors => new [] {Color.red, Color.yellow};
    private Vector3[] Points => new[] {pointA.position, pointB.position};
    private int Index0 => flipOrder ? 1 : 0;
    private int Index1 => flipOrder ? 0 : 1;
    
    public override void DrawShapes(Camera cam) {
        if (pointA == null || pointB == null) return;
        using (Draw.Command(cam)) {
            Draw.ResetAllDrawStates();

            Draw.BlendMode = ShapesBlendMode.Opaque;
            Draw.LineThicknessSpace = ThicknessSpace.Pixels;
            Draw.LineGeometry = volumetric ? LineGeometry.Volumetric3D : LineGeometry.Billboard;
            Draw.Line(Points[Index0], Points[Index1],
                pixelThickness, Colors[Index0], Colors[Index1]);

            // Reference Spheres (show expected thickness)
            Draw.BlendMode = ShapesBlendMode.Transparent;
            Draw.SphereRadiusSpace = ThicknessSpace.Pixels;
            for (int i = 0; i < Points.Length; ++i) {
                Draw.Sphere(Points[i], pixelThickness / 2, refColor);
            }
        }
    }
    
#if UNITY_EDITOR
    // Stuff to help debug draw view frustums and on-screen debug text
    public override void OnEnable() {
        base.OnEnable();
        EditorApplication.update += RedrawAllSceneViews;
    }
    public override void OnDisable() {
        base.OnDisable();
        EditorApplication.update -= RedrawAllSceneViews;
    }
    private static void RedrawAllSceneViews() {
        foreach (SceneView view in SceneView.sceneViews) {
            view.Repaint();
        }
    }
    private void OnDrawGizmos() {
        Camera curCam = Camera.current;
        Color frustumColor = Color.cyan;
        frustumColor.a = 0.5f;
        var sceneCams = SceneView.GetAllSceneCameras();
        for (int i = 0; i < sceneCams.Length; ++i) {
            var sceneCam = sceneCams[i];
            if (sceneCam == curCam) continue;
            float param01 = (float)i / Mathf.Max(sceneCams.Length, 1);
            Color color = Color.HSVToRGB(param01, 0.6f, 1);
            color.a = 0.4f;
            Gizmos.color = color;
            Gizmos.matrix = sceneCam.transform.localToWorldMatrix;
            Gizmos.DrawFrustum(Vector3.zero, sceneCam.fieldOfView, 
                1, sceneCam.nearClipPlane, sceneCam.aspect);
        }
        
        if (pointA == null || pointB == null) return;
        Vector3 viewPoint0 = curCam.WorldToViewportPoint(Points[Index0]);
        DrawScreenText(curCam, new Vector2(10, 10), 
            $"Point0: {viewPoint0.x:0.00}, {viewPoint0.y:0.00}, {viewPoint0.z:0.00}", Colors[Index0]);
        
        Vector3 viewPoint1 = curCam.WorldToViewportPoint(Points[Index1]);
        DrawScreenText(curCam, new Vector2(10, 25), 
            $"Point1: {viewPoint1.x:0.00}, {viewPoint1.y:0.00}, {viewPoint1.z:0.00}", Colors[Index1]);
    }

    private static void DrawScreenText(Camera cam, Vector2 screenPos, string text, Color color) {
        GUIStyle style = new GUIStyle { normal = { textColor = color } };
        Vector3 topLeft = new Vector3(screenPos.x, cam.pixelHeight - screenPos.y, 1);
        Handles.Label(cam.ScreenToWorldPoint(topLeft), text, style);
    }
#endif
}