1 前言

        选中物体消融特效中基于 Shader 实现了消融特效，本文将基于 Shader Graph 实现消融特效，两者原理一样，只是表达方式不同，另外，选中物体消融特效中通过 discard 丢弃片元，本文通过 alpha 测试丢弃片元。

        Shader Graph环境搭建、简单应用详见→Shader Graph简介。

        本文完整资源见→Unity3D消融特效。

2 消融特效实现

        创建 Unlit Shader Graph，重命名为 DissolveEffect，编辑如下。 

        其中，Alpha 测试需要在 Graph Settings 中开启，如下。

        为实现点击消失效果，需要编写脚本如下。

        DieController.cs

using UnityEngine;public class DieController : MonoBehaviour {private RaycastHit hit; // 碰撞信息private void Start() {hit = new RaycastHit();}private void Update() {if (Input.GetMouseButtonUp(0)) {GameObject hitObj = GetHitObj();if (hitObj != null) {GameObject rootObj = GetRootObj(hitObj);rootObj.AddComponent<DissolveEffect>();}}}private GameObject GetHitObj() { // 获取屏幕射线碰撞的物体Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);if (Physics.Raycast(ray, out hit)) {return hit.collider.gameObject;}return null;}private GameObject GetRootObj(GameObject obj) { // 获取根对象while (obj.transform.parent != null && obj.layer == obj.transform.parent.gameObject.layer) {obj = obj.transform.parent.gameObject;}return obj;}
}

        DissolveEffect.cs

using UnityEngine;[DisallowMultipleComponent] // 不允许在同一对象上挂载多个该组件
public class DissolveEffect : MonoBehaviour {private Renderer[] renderers; // 渲染器private Material dissolveMat; // 消融材质private float burnSpeed = 0.25f; // 燃烧速度private float burnAmount = 0; // 燃烧量, 值越大模型镂空的越多private void Awake() {dissolveMat = Resources.Load<Material>("DissolveMat");renderers = GetComponentsInChildren<Renderer>();}private void OnEnable() {foreach (Renderer renderer in renderers) {Material[] materials = renderer.sharedMaterials;Material[] dissolveMaterials = new Material[materials.Length];for (int i = 0; i < materials.Length; i++) {Material newMaterial = new Material(dissolveMat);SetTexture(materials[i], newMaterial);SetColor(materials[i], newMaterial);newMaterial.SetFloat("_BurnAmount", 0);dissolveMaterials[i] = newMaterial;}renderer.sharedMaterials = dissolveMaterials;}}private void Update() {burnAmount += Time.deltaTime * burnSpeed;foreach (Renderer renderer in renderers) {Material[] materials = renderer.sharedMaterials;foreach (Material material in materials) {material.SetFloat("_BurnAmount", burnAmount);}}if (burnAmount >= 1f) {Destroy(gameObject);}}private void SetTexture(Material oldMaterial, Material newMaterial) { // 设置材质if (oldMaterial.HasTexture("_MainTex")) {Texture texture = oldMaterial.GetTexture("_MainTex");newMaterial.SetTexture("_MainTex", texture);}}private void SetColor(Material oldMaterial, Material newMaterial) { // 设置颜色Color color = Color.white;if (oldMaterial.HasColor("_Color")) {color = oldMaterial.GetColor("_Color");}newMaterial.SetColor("_Color", color);}
}

        运行效果如下。