Link log: ERROR: Compiled vertex shader was corrupt.
ERROR: Compiled fragment shader was corrupt.

經過排查，是swift中的String 轉為 UnsafePointer<GLchar>? 過程，出現(xiàn)了未知問題。
作者原方法(OpenGLRendering.swift文件中的String擴展)：

  func withGLChar(_ operation:(UnsafePointer<GLchar>) -> ()) {
        if let value = self.cString(using:String.Encoding.utf8) {
            operation(UnsafePointer<GLchar>(value))
        } else {
            fatalError("Could not convert this string to UTF8: \(self)")
        }
  }

修改為：

    func withGLChar(_ operation:(UnsafePointer<GLchar>) -> ()) {
        if let value = NSString.init(string: self).utf8String {
            operation(value)
        } else {
            fatalError("Could not convert this string to UTF8: \(self)")
        }
    }

使用NSString 即可，原因未知
參考提交：https://github.com/liuqiaohong0515/GPUImage2/commit/5a3c23a30b54d459488da351c8e6133cfa0baf75