原因：由于GPUImage代码过于老旧所以并不支持超广角的设置

修改文件--所有代码都是在GPUImageVideoCamera.m文件中修改

第1步--先封装一个获取当前设备的函数放在.m文件最后

- (AVCaptureDevice *)wjx_getCaptureDeviceWithPosition:(AVCaptureDevicePosition)positon{
    NSArray<AVCaptureDeviceType> *deviceTypes = @[AVCaptureDeviceTypeBuiltInWideAngleCamera, AVCaptureDeviceTypeBuiltInDualCamera];//设备类型：广角镜头、双镜头
    if (@available(iOS 13.0, *)) {
        // 数组成员的顺序，决定搜索设备的顺序，不要随意调整。
        deviceTypes = @[AVCaptureDeviceTypeBuiltInTripleCamera,AVCaptureDeviceTypeBuiltInDualWideCamera,AVCaptureDeviceTypeBuiltInWideAngleCamera, AVCaptureDeviceTypeBuiltInDualCamera];
    }
    AVCaptureDeviceDiscoverySession *dissession = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:deviceTypes mediaType:AVMediaTypeVideo position:positon];
//    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *device in dissession.devices)
    {
        if ([device position] == positon)
        {
            return device;
        }
    }
}

第2步--把所有获取摄像头的位置都换成上面的方法

//第1处
- (id)initWithSessionPreset:(NSString *)sessionPreset cameraPosition:(AVCaptureDevicePosition)cameraPosition; 
{
    /*
        ...省略
    **/
    
    // Grab the back-facing or front-facing camera
    _inputCamera = nil;
//  NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
//  for (AVCaptureDevice *device in devices) 
//  {
//      if ([device position] == cameraPosition)
//      {
//          _inputCamera = device;
//      }
//  }

//上面代码注释掉换成下面

    _inputCamera = [self wjx_getCaptureDeviceWithPosition:cameraPosition];
    
    if (!_inputCamera) {
        return nil;
    }

    /*
        ...省略
    **/
}
    

//第2处
- (void)rotateCamera
{
    /*
        ...省略
    **/
    
//    AVCaptureDevice *backFacingCamera = nil;
//    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
//  for (AVCaptureDevice *device in devices) 
//  {
//      if ([device position] == currentCameraPosition)
//      {
//          backFacingCamera = device;
//      }
//  }
//上面代码注释掉换成下面

    AVCaptureDevice *backFacingCamera = [self wjx_getCaptureDeviceWithPosition:currentCameraPosition];
    newVideoInput = [[AVCaptureDeviceInput alloc] initWithDevice:backFacingCamera error:&error];

    /*
        ...省略
    **/
}