05 GUPImage混合模式滤镜的使用

  前几天一直在研究GPUImage,忽然发现混合模式的滤镜没有使用方法,各种搜索后发现也只是对GPUImage的简单使用,甚至在GPUImage的GitHub上的Demo里面都没有找到这一部分的内容的介绍,花费了很大力气后终于琢磨出来一点用法,可以对两个视频添加滤镜,效果是讲两个视频集成为一个视频,同时显示,中间会有渐变或者高亮等滤镜效果

 下面是代码

</pre><pre name="code" class="objc">- (IBAction)blendFilter:(id)sender {    NSString *sandBoxPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject];        // 要添加滤镜的视频1    GPUImageMovie *movieFile = [[GPUImageMovie alloc] initWithURL:[NSURL fileURLWithPath:[sandBoxPath stringByAppendingPathComponent:@"movie"]]];        movieFile.runBenchmark = YES;    movieFile.playAtActualSpeed = NO;        // 要添加滤镜的视频2    GPUImageMovie *movieFile2 = [[GPUImageMovie alloc] initWithURL:[[NSBundle mainBundle] URLForResource:@"video" withExtension:@"mov"]];      movieFile2.runBenchmark = YES;    movieFile2.playAtActualSpeed = NO;//    GPUImageScreenBlendFilter *filter = [[GPUImageScreenBlendFilter alloc] init];    GPUImageDivideBlendFilter *filter = [[GPUImageDivideBlendFilter alloc] init];    [movieFile addTarget:filter];    [movieFile2 addTarget:filter];        // 添加滤镜后的视频保存的位置    NSString *pathToMovie = [sandBoxPath stringByAppendingPathComponent:@"last.mov"];    unlink([pathToMovie UTF8String]); // If a file already exists, AVAssetWriter won't let you record new frames, so delete the old movie        NSLog(@"%@",pathToMovie);    NSURL *movieURL = [NSURL fileURLWithPath:pathToMovie];        GPUImageMovieWriter *movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(480.0, 640.0)];    [filter addTarget:movieWriter];    // Configure this for video from the movie file, where we want to preserve all video frames and audio samples    movieWriter.shouldPassthroughAudio = YES;    //movieFile.audioEncodingTarget = self.movieWriter;    [movieFile enableSynchronizedEncodingUsingMovieWriter:movieWriter];        [movieWriter startRecording];    [movieFile startProcessing];    [movieFile2 startProcessing];        // 结束后的回调    [movieWriter setCompletionBlock:^{        [filter removeTarget:movieWriter];        [movieFile endProcessing];        [movieFile2 endProcessing];        [movieWriter finishRecording];        NSLog(@"ok");    }];    }