新GPUImage无法获取processedImage

我对最新的重构有问题。每次我试图从过滤器中获取经过处理的UIImage时,它都是零。我用过 useNextFrameForImageCapture 但它仍然不起作用。 下面是我的代码片段:

self.imageView = [[GPUImageView alloc] initWithFrame:CGRectMake(0,
                                            0,
                                            self.view.frame.size.width,
                                            self.view.frame.size.height)];
staticPicture = [[GPUImagePicture alloc] initWithImage:img
                                   smoothlyScaleOutput:YES];
filter = [[GPUImageToneCurveFilter alloc] initWithACV:@"cool"];
[staticPicture addTarget:filter];
[filter addTarget:self.imageView];

GPUImageRotationMode imageViewRotationMode = kGPUImageNoRotation;
switch (staticPictureOriginalOrientation) {
    case UIImageOrientationLeft:
        imageViewRotationMode = kGPUImageRotateLeft;
        break;
    case UIImageOrientationRight:
        imageViewRotationMode = kGPUImageRotateRight;
        break;
    case UIImageOrientationDown:
        imageViewRotationMode = kGPUImageRotate180;
        break;
    default:
        imageViewRotationMode = kGPUImageNoRotation;
        break;
}

// seems like atIndex is ignored by GPUImageView...
[self.imageView setInputRotation:imageViewRotationMode atIndex:0];

[staticPicture useNextFrameForImageCapture];
[staticPicture processImage];
UIImage *processedImage = [filter imageFromCurrentFramebufferWithOrientation:staticPictureOriginalOrientation];

processedImage始终为空。非常感谢您的帮助!