今天Egret Engine5.3.10版正式发布，主要内容是修复iOS14 系统上 mesh 卡顿、htmlsound 声音挂载到后台后无法返回以及龙骨模型显示异常三个问题。

截至目前，虽然Egret Engine5.3系列依然属测试版，但产品功能已趋于稳定，建议有卡顿问题的开发者升级处理！

如若您的上线项目使用的是Egret Engine 5.2系列的稳定版，且不想升级引擎版本解决卡顿问题，我们为您提供了第二套解决方案，需要您在Egret Engine 5.2.X版本中手动修改以下2个位置的代码：

位置1：WebGLVertexArrayObject.ts
cacheArrays方法

 .......

            if (meshVertices) {
                let vertData = [];
                // 计算索引位置与赋值
                const vertices = this.vertices;
                const verticesUint32View = this._verticesUint32View;
                let index = this.vertexIndex * this.vertSize;
                // 缓存顶点数组
                let i = 0, iD = 0, l = 0;
                let u = 0, v = 0, x = 0, y = 0;
                for (i = 0, l = meshUVs.length; i < l; i += 2) {
                    iD = index + i * 5 / 2;
                    x = meshVertices[i];
                    y = meshVertices[i + 1];
                    u = meshUVs[i];
                    v = meshUVs[i + 1];

                    if (rotated) {
                        vertData.push([
                            a * x + c * y + tx,
                            b * x + d * y + ty,
                            (sourceX + (1.0 - v) * sourceHeight) / textureSourceWidth,
                            (sourceY + u * sourceWidth) / textureSourceHeight,
                        ]);
                    } else {
                        vertData.push([
                            a * x + c * y + tx,
                            b * x + d * y + ty,
                            (sourceX + u * sourceWidth) / textureSourceWidth,
                            (sourceY + v * sourceHeight) / textureSourceHeight,
                        ]);
                    }
                    verticesUint32View[iD + 4] = alpha;
                }
                for (let i = 0; i < meshIndices.length; i += 3) {
                    let data0 = vertData[meshIndices[i]];
                    vertices[index++] = data0[0];
                    vertices[index++] = data0[1];
                    vertices[index++] = data0[2];
                    vertices[index++] = data0[3];
                    verticesUint32View[index++] = alpha;

                    let data1 = vertData[meshIndices[i + 1]];
                    vertices[index++] = data1[0];
                    vertices[index++] = data1[1];
                    vertices[index++] = data1[2];
                    vertices[index++] = data1[3];
                    verticesUint32View[index++] = alpha;

                    let data2 = vertData[meshIndices[i + 2]];
                    vertices[index++] = data2[0];
                    vertices[index++] = data2[1];
                    vertices[index++] = data2[2];
                    vertices[index++] = data2[3];
                    verticesUint32View[index++] = alpha;

                    // 填充数据
                    vertices[index++] = data2[0];
                    vertices[index++] = data2[1];
                    vertices[index++] = data2[2];
                    vertices[index++] = data2[3];
                    verticesUint32View[index++] = alpha;
                }

                let meshNum = meshIndices.length / 3;
                this.vertexIndex += 4 * meshNum;
                this.indexIndex += 6 * meshNum;

            } else {
              ......

位置2：WebGLRenderContext.ts
drawTexture方法

  let buffer = this.currentBuffer;
            if (this.contextLost || !texture || !buffer) {
                return;
            }

            let meshNum = meshIndices && (meshIndices.length / 3) || 0;
            if (meshIndices) {
                if (this.vao.reachMaxSize(meshNum * 4, meshNum * 6)) {
                    this.$drawWebGL();
                }
            } else {
                if (this.vao.reachMaxSize()) {
                    this.$drawWebGL();
                }
            }

            if (smoothing != undefined && texture["smoothing"] != smoothing) {
                this.drawCmdManager.pushChangeSmoothing(texture, smoothing);
            }

            // if (meshUVs) {
            //     this.vao.changeToMeshIndices();
            // }

            let count = meshIndices ? meshNum * 2 : 2;
            .........

以上2种方案均可解决基于iOS14系统带来的卡顿问题，大家可根据项目情况自行选择。使用Egret Engine期间如若遇到问题，可联系官方客服微信号：egretengine，我们会第一时间帮您解决！