GPUImage presentBufferForDispla

项目中使用GPUImage自定义相机录制短视频,测试发现锁屏后再进入App会Crash,每次都崩溃在以下代码:

- (void)presentBufferForDisplay;
{
    [self.context presentRenderbuffer:GL_RENDERBUFFER];
}

在 GPUImage的Issues#197找到了答案,大概原因是iOS不支持后台进行OpenGL渲染,所以切后台之前要调用glfinish()，将缓冲区中的指令(无论是否为满)立刻送给图形硬件执行，glfinish()会等待图形硬件执行完才返回。

- (void)observeGlobalNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onApplicationWillResignActive) name:UIApplicationWillResignActiveNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onApplicationDidBecomeActive) name:UIApplicationDidBecomeActiveNotification object:nil];
}

- (void)unobserveGlobalNotifications
{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationWillResignActiveNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationDidBecomeActiveNotification object:nil];
}

- (void)onApplicationWillResignActive
{     
    //[self.camera pauseCameraCapture];
    [self.camera stopCameraCapture];

    runSynchronouslyOnVideoProcessingQueue(^{
        glFinish();
    });
}

- (void)onApplicationDidBecomeActive
{
   // [self.camera resumeCameraCapture];
    [self.camera startCameraCapture];
}