Outline - Part 5

using UnityEngine;

[DisallowMultipleComponent]
public class Outline : MonoBehaviour
{
    public enum Mode
    {
        OutlineAll,
        OutlineVisible,
        OutlineHidden,
        OutlineAndSilhouette,
        SilhouetteOnly
    }

    public Mode OutlineMode
    {
        get { return outlineMode; }
        set
        {
            outlineMode = value;
            needsUpdate = true;
        }
    }

    public Color OutlineColor
    {
        get { return outlineColor; }
        set
        {
            outlineColor = value;
            needsUpdate = true;
        }
    }

    public float OutlineWidth
    {
        get { return outlineWidth; }
        set
        {
            outlineWidth = value;
            needsUpdate = true;
        }
    }

    [SerializeField]
    private Mode outlineMode;

    [SerializeField]
    private Color outlineColor = Color.blue;

    [SerializeField, Range(0f, 10f)]
    private float outlineWidth = 5f;

    private Renderer[] renderers;
    private Material outlineMaskMaterial;
    private Material outlineFillMaterial;

    private bool needsUpdate;

    void Awake()
    {
        renderers = GetComponentsInChildren<Renderer>();

        outlineMaskMaterial = Instantiate(Resources.Load<Material>(@"Materials/OutlineMask"));
        outlineFillMaterial = Instantiate(Resources.Load<Material>(@"Materials/OutlineFill"));

        outlineMaskMaterial.name = "OutlineMask (Instance)";
        outlineFillMaterial.name = "OutlineFill (Instance)";

        needsUpdate = true;
    }

    void OnEnable()
    {
        foreach (var renderer in renderers)
        {
            var materials = renderer.sharedMaterials.Clone() as Material[];
            System.Array.Resize(ref materials, materials.Length + 2);
            materials[materials.Length - 2] = outlineMaskMaterial;
            materials[materials.Length - 1] = outlineFillMaterial;
            renderer.materials = materials;
        }
    }

    void OnDisable()
    {
        foreach (var renderer in renderers)
        {
            var materials = renderer.sharedMaterials.Clone() as Material[];
            System.Array.Resize(ref materials, materials.Length - 2);
            renderer.materials = materials;
        }
    }

    void Update()
    {
        if (needsUpdate)
        {
            needsUpdate = false;
            UpdateMaterialProperties();
        }
    }

    void UpdateMaterialProperties()
    {
        outlineFillMaterial.SetColor("_OutlineColor", outlineColor);

        switch (outlineMode)
        {
            case Mode.OutlineAll:
                outlineMaskMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.Always);
                outlineFillMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.Always);
                outlineFillMaterial.SetFloat("_OutlineWidth", outlineWidth);
                break;

            case Mode.OutlineVisible:
                outlineMaskMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.Always);
                outlineFillMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.LessEqual);
                outlineFillMaterial.SetFloat("_OutlineWidth", outlineWidth);
                break;

            case Mode.OutlineHidden:
                outlineMaskMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.Always);
                outlineFillMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.Greater);
                outlineFillMaterial.SetFloat("_OutlineWidth", outlineWidth);
                break;

            case Mode.OutlineAndSilhouette:
                outlineMaskMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.LessEqual);
                outlineFillMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.Always);
                outlineFillMaterial.SetFloat("_OutlineWidth", outlineWidth);
                break;

            case Mode.SilhouetteOnly:
                outlineMaskMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.LessEqual);
                outlineFillMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.Greater);
                outlineFillMaterial.SetFloat("_OutlineWidth", 0);
                break;
        }
    }

}