[LayaAir 2.0]话说Laya3D怎么自定义shader来实现后期处理呢?

还有我发现这句代码没用啊,,, 通过shader处理没有起作用啊

cmd.blitScreenTriangle(sourceTexture, destTexture, null, this._shader, this._shaderData, 0);

Try......................
 render(context: { command: any; camera: { viewport: any; }; source: Laya.RenderTexture; deferredReleaseTextures: any; })
    {
.......
        var sourceTex = context.source;
        var targetTex = Laya.RenderTexture.createFromPool(tw, th, Laya.RenderTexture.FORMAT_R8G8B8, Laya.RenderTexture.FORMAT_DEPTHSTENCIL_NONE, Laya.BaseTexture.FILTERMODE_BILINEAR);
        cmd.blitScreenTriangle(sourceTex, targetTex, null, this.mShader, this.mShaderData, 0);
        context.source = targetTex;
        Laya.RenderTexture.recoverToPool(targetTex);
        context.deferredReleaseTextures.push(sourceTex);
    }