//(1) 找插槽
Slot slot = skeleton.findSlot("插槽名")

//(2) 获取附件
Attachment attachment = slot.getAttachment();

//(3) 创建并加载纹理
Texture texture = new Texture(Gdx.files.internal("纹理地址"));
//设置纹理参数
texture.setFilter(Texture.TextureFilter.MipMap, Texture.TextureFilter.MipMap);
texture.setWrap(Texture.TextureWrap.ClampToEdge, Texture.TextureWrap.ClampToEdge);

//(4) 创建纹理区域对象
TextureAtlas.AtlasRegion region = new TextureAtlas.AtlasRegion(new TextureRegion(texture));

//(5) 替换附件
//区域附件
if (attachment instanceof RegionAttachment)
{
	RegionAttachment regionAttachment = (RegionAttachment) attachment;
	regionAttachment.setRegion(region);
	regionAttachment.updateOffset();
}
//网格附件
else if (attachment instanceof MeshAttachment)
	{
	MeshAttachment meshAttachment = (MeshAttachment) attachment;
	meshAttachment.setRegion(region);
	meshAttachment.updateUVs();
}

//(6) 移除附件(卸装)
slot.setAttachment(null);

//(1) 获取画布
var canvas = document.getElementById("canvas");
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;

//(2) 获取webgl
var config = { alpha: false };
var gl = canvas.getContext("webgl", config) || canvas.getContext("experimental-webgl", config);
if (!gl) {
	alert('WebGL is unavailable.');
}

//骨骼文件名
var skeletonName = "2dnansheng.skel";
//图集文件名
var atlasName = "2dnansheng.atlas";

//创建资源管理器
var assetManager = new spine.AssetManager(gl, "assets/");
//加载二进制骨骼文件
assetManager.loadBinary(skeletonName);
//加载图集
assetManager.loadTextureAtlas(atlasName);
//执行加载
requestAnimationFrame(load);

//加载函数
function load() {
	if (assetManager.isLoadingComplete()) {
		//获取图集
		var atlas = assetManager.require(atlasName);
		//创建图集附件加载器
		var atlasLoader = new spine.AtlasAttachmentLoader(atlas);
		//创建骨骼加载器
		var skeletonLoader = new spine.SkeletonBinary(atlasLoader);
		skeletonLoader.scale = 1;
		//读取骨骼数据
		var skeletonData = skeletonLoader.readSkeletonData(assetManager.require(skeletonName));
		//创建骨骼
		var skeleton = new spine.Skeleton(skeletonData);
	} else {
		//继续调用load()，直到所有资源加载完成
		requestAnimationFrame(load);
	}
}

//加载换装图片assets/xxx.png
assetManager.loadTexture("xxx.png");
//执行加载
requestAnimationFrame(load);

//加载函数
function load() {
	if (assetManager.isLoadingComplete()) {
		//获取插槽
		var slot = skeleton.findSlot("插槽名");
		//获取插槽下面的当前附件
		var attachment = slot.getAttachment();
		//提取图片
		var texture = assetManager.require("xxx.png");
		//获取Image对象
		var image = texture.getImage();
		//创建GLTexture
		var glTexture = new spine.GLTexture(gl, image);
		//设置纹理滤波
		glTexture.setFilters(spine.TextureFilter.MipMap, spine.TextureFilter.MipMap);
		//设置纹理环绕模式
		glTexture.setWraps(spine.TextureWrap.ClampToEdge, spine.TextureWrap.ClampToEdge);
		
		//判断附件类型
		if (attachment instanceof spine.RegionAttachment) {
			//创建纹理区域
			var textureRegion = new spine.TextureRegion();
			textureRegion.renderObject = glTexture;//绑定要渲染的纹理
			//替换附件
			attachment.setRegion(textureRegion);
			//更新位置
			attachment.updateOffset();
		} else if (attachment instanceof spine.MeshAttachment) {
			//替换附件
			//attachment.setRegion(textureRegion);//没这个函数

			var image = glTexture.getImage();
			var page = new spine.TextureAtlasPage();
			page.name = glTexture.name;
			page.minFilter = spine.TextureFilter.MipMap;
			page.magFilter = spine.TextureFilter.MipMap;
			page.uWrap = spine.TextureWrap.ClampToEdge;
			page.vWrap = spine.TextureWrap.ClampToEdge;
			page.width = image.width;
			page.height = image.height;
			page.setTexture(glTexture);

			var region = new spine.TextureAtlasRegion();
			region.page = page;
			region.width = image.width;
			region.height = image.height;
			region.originalWidth = image.width;
			region.originalHeight = image.height;
			region.u = region.v = 0;
			region.u2 = region.v2 = 1;
			region.renderObject = glTexture;
						
			//替换附件
			attachment.region = region;
			//更新UV
			attachment.updateUVs();
		}
	} else {
		//继续调用load()，直到所有资源加载完成
		requestAnimationFrame(load);
	}
}

using UnityEngine;
using Spine;
/// <summary>
/// Spine辅助工具类
/// </summary>
public sealed class SpineHelper
{
    /// <summary>
    /// 使用外部图片替换插槽下的附件图片
    /// </summary>
    /// <param name="skeleton">骨骼对象</param>
    /// <param name="slotName">插槽名称</param>
    /// <param name="texture2D">外部图片</param>
    public static void ReplaceSkin(Skeleton skeleton, string slotName, string attachmentName, Texture2D texture2D)
    {
        if (skeleton == null || texture2D == null)
            return;

        Slot slot = skeleton.FindSlot(slotName);
        if (slot == null)
            return;

        //当插槽下的所有附件处于隐藏状态时,slot.Attachment为null
        //如果想要获取到隐藏状态的附件,可以使用skeleton.GetAttachment()方法
        Attachment attachment = skeleton.GetAttachment(slotName, attachmentName);
        if (attachment == null)
            return;

        Material material = new Material(Shader.Find("Spine/Skeleton"));
        material.mainTexture = texture2D;

        AtlasPage page = new AtlasPage();
        page.rendererObject = material;
        page.name = texture2D.name;
        page.minFilter = TextureFilter.MipMap;
        page.magFilter = TextureFilter.MipMap;
        page.uWrap = TextureWrap.ClampToEdge;
        page.vWrap = TextureWrap.ClampToEdge;
        page.width = texture2D.width;
        page.height = texture2D.height;

        AtlasRegion region = new AtlasRegion();
        region.page = page;
        region.width = texture2D.width;
        region.height = texture2D.height;
        region.originalWidth = texture2D.width;
        region.originalHeight = texture2D.height;
        region.u = region.v = 0;
        region.u2 = region.v2 = 1;
        region.rotate = false;

        if (attachment is RegionAttachment)
        {
            RegionAttachment regionAttachment = attachment as RegionAttachment;
            regionAttachment.RendererObject = region;
            regionAttachment.SetUVs(0f, 1f, 1f, 0f, 0);
            regionAttachment.UpdateOffset();
        }
        else if (attachment is MeshAttachment)
        {
            MeshAttachment meshAttachment = attachment as MeshAttachment;
            meshAttachment.RendererObject = region;
            meshAttachment.RegionU = 0f;
            meshAttachment.RegionV = 1f;
            meshAttachment.RegionU2 = 1f;
            meshAttachment.RegionV2 = 0f;
            meshAttachment.UpdateUVs();
        }
    }
}