GPUImage-使用NSMutableArray串联应用过滤器

我正在尝试构建一个动态系统以串联应用多个GPUImage滤镜。

如果我像这样静态定义所有过滤器：

[sourceImage addTarget:filter1];
[filter1 addTarget:filter2];
[filter2 addTarget:filter3];

...等等，这很好。

由于我想拥有可变数量的过滤器，因此变得很麻烦。我想我会尝试使用mutableArray并存储过滤器来执行此操作。不幸的是我遇到了错误：

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Tried to overrelease a framebuffer, did you forget to call -useNextFrameForImageCapture before using -imageFromCurrentFramebuffer?'

研究此错误表明，问题在于过滤器不再是“强”引用，并且一旦对数组进行迭代，它们将被销毁。

如果我对这个假设是正确的，是否有办法重写它，从而不会破坏引用？

这是我的类别实现：

@implementation UIImage (FilterEngine)

- (UIImage*)imageProcessedWithFilterEngine:(FilterProperties*)properties
{

    // Mutable array of filters, for dynamic iteration through only those filters which require applying
    NSMutableArray* filtersList = [NSMutableArray new];

    GPUImagePicture *source = [[GPUImagePicture alloc] initWithImage:self];

    GPUImageCustomFilterEngine* filterEngine;
    if (properties.lookupImageName)
    {
        filterEngine = [[GPUImageCustomFilterEngine alloc] initWithLookupImageName:properties.lookupImageName];
        [filtersList addObject:filterEngine];
    }

    GPUImageBrightnessFilter *brightnessFilter = [GPUImageBrightnessFilter new];
    if (properties.brightness != 0.0)
    {
        brightnessFilter.brightness = properties.brightness;
        [filtersList addObject:brightnessFilter];
    }

    GPUImageContrastFilter *contrastFilter = [GPUImageContrastFilter new];
    if (properties.contrast != 1.0)
    {
        contrastFilter.contrast = properties.contrast;
        [filtersList addObject:contrastFilter];
    }

    GPUImageSaturationFilter *saturationFilter = [GPUImageSaturationFilter new];
    if (properties.saturation != 1.0)
    {
        saturationFilter.saturation = properties.saturation;
        [filtersList addObject:saturationFilter];
    }

    if (filtersList.count > 0)
    {
        [source addTarget:filtersList.firstObject];
        for (int i = 0; i < filtersList.count - 1; i++)
        {
            [(id)[filtersList objectAtIndex:i] addTarget:[filtersList objectAtIndex:i + 1]];
        }

        [source addTarget:filtersList.lastObject];

        [(id)filtersList.lastObject useNextFrameForImageCapture];

        [source processImage];

        return [filtersList.lastObject imageFromCurrentFramebuffer];
    }
    else
        return self;
}

@end