合并两个float，返回一个short

调节采样的音量---非清唱时候最终合成伴奏与录音的时候，判断如果accompanyVolume不是1.0的话，先调节伴奏的音量；而audioVolume是在读出的字节流转换为short流的时候调节的。

Retrieves the int representation of the Rotation. @return 0, 90, 180 or 270

Checks to see if the location we obtained is valid. GLES returns -1 if a label could not be found, but does not set the GL error. <p> Throws a Runtim

客户端代码需要根据accompanySampleRate / audioSampleRate算出transfer_ratio; 以及根据(int)((float)(sample_count) / accompanySampleRate * audioSampleRate)算出transfered_s

将一个short数组转换为一个byte数组---清唱时由于不需要和伴奏合成，所以直接转换;还有一个是当解码完成之后，需要将short变为byte数组，写入文件

将一个byte数组转换为一个short数组---读进来audioRecord录制的pcm，然后将其从文件中读出字节流，然后在转换为short以方便后续处理

Allocates a direct float buffer, and populates it with the float array data.

Creates a texture from raw data. @param data Image data, in a "direct" ByteBuffer. @param width Texture width, in pixels (not bytes). @param height T

Creates an EGL surface associated with an offscreen buffer.

Creates a new program from the supplied vertex and fragment shaders. @return A handle to the program, or 0 on failure.

Returns the GLES version this context is configured for (currently 2 or 3).