新的GPUImage无法获得processedImage

Question

我遇到了最新的重构问题。每次我尝试从过滤器中获取已处理的UIImage时，它都是零。我使用过useNextFrameForImageCapture但它仍然不起作用。  以下是我的代码片段：

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总是为零。非常感谢任何帮助！

Answer 1

@BradLarson回答了我的问题：您需要在要捕获的过滤器上使用-useNextFrameForImageCapture，而不是输入图像。它必须告诉过滤器保持其帧缓冲。在您的情况下，您需要调用[filter useNextFrameForImageCapture]。