adding GPUImage framework to IOS project - ios

Question

The hours are turning into days trying to add the GPUImage framework into an IOS project. Now I've got it working I'm trying the sample filtering live video code from Sunset Lake Software page. The app fails to build with the following red error: ' Use of undeclared 'thresholdfFilter'
GPUImageVideoCamera *videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack];
GPUImageFilter *customFilter = [[GPUImageFilter alloc] initWithFragmentShaderFromFile:#"CustomShader"];
GPUImageView *filteredVideoView = [[GPUImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, 768, 1024)];
// problem here
[videoCamera addTarget:thresholdFilter];
[customFilter addTarget:filteredVideoView];
[videoCamera startCameraCapture];
Using Xcode 6.0.1 and testing app on iPad2 with IOS 8.0.2 - If required, I can post screen shots of how I emdedded the framework.

Answer 1

First, the code written in my initial blog post announcing the framework should not be copied to use with the modern version of the framework. That initial post was written over two years ago, and does not reflect the current state of the API. In fact, I've just deleted all of that code from the original post and directed folks to the instructions on the GitHub page which are kept up to date. Thanks for the reminder.
Second, the problem you're describing above is that you're attempting to use a variable called thresholdFilter without ever defining such a variable. That's not a problem with the framework, the compiler has no idea what you're referring to.
Third, the above code won't work for another reason: you're not holding on to your camera instance. You're defining it locally, instead of assigning it to an instance variable of your encapsulating class. This will lead to ARC deallocating that camera as soon as your above setup method is complete, leading to a black screen or to a crash. You need to create an instance variable or property and assign your camera to that, so that a strong reference is made to it.