ios - GPUImageGaussianBlurFilter 似乎不适用于分层过滤器

Question

我有分层滤镜，它们在我使用的图像中看起来都很棒，但如果我将高斯模糊参数更改得更高或更低，模糊效果没有明显差异。我做错了什么？

这是我的代码:

GPUImageView *finalView;

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIImage *topLayer = [UIImage imageNamed:@"Glass.png"];
    UIImage *baseLayer = [UIImage imageNamed:@"BasePhoto.png"];

    GPUImagePicture *stillImageSourceTop = [[GPUImagePicture alloc] initWithImage:topLayer];
    GPUImagePicture *stillImageSourceBottom = [[GPUImagePicture alloc] initWithImage:baseLayer];

    GPUImageScreenBlendFilter *screenBlendFilter = [[GPUImageScreenBlendFilter alloc] init];
    GPUImageBrightnessFilter *brightnessFilter = [[GPUImageBrightnessFilter alloc] init];
    GPUImageContrastFilter *contrastFilter = [[GPUImageContrastFilter alloc] init];
    GPUImageSaturationFilter *saturationFilter = [[GPUImageSaturationFilter alloc] init];
    GPUImageColorMatrixFilter *colorMatrixFilter = [[GPUImageColorMatrixFilter alloc] init];
    GPUImageOpacityFilter *opacityFilter = [[GPUImageOpacityFilter alloc] init];
    opacityFilter.opacity = 0;

    GPUImageGaussianBlurFilter *blurFilter = [[GPUImageGaussianBlurFilter alloc]init];
    blurFilter.texelSpacingMultiplier = 4.0;
    blurFilter.blurRadiusInPixels = 200.0;
    blurFilter.blurPasses = 4;


    [stillImageSourceTop addTarget:brightnessFilter];
    [brightnessFilter addTarget:contrastFilter];
    [contrastFilter addTarget:saturationFilter];
    [saturationFilter addTarget:colorMatrixFilter];
    [colorMatrixFilter addTarget:blurFilter];
    [blurFilter addTarget:opacityFilter];

    [stillImageSourceTop processImage]; 
    [opacityFilter useNextFrameForImageCapture];

    UIImage *topLayerImage = [opacityFilter imageFromCurrentFramebuffer];
    GPUImagePicture *stillImageSourceTopWithFilters = [[GPUImagePicture alloc] initWithImage:topLayerImage];

    [stillImageSourceBottom addTarget:screenBlendFilter];
    [stillImageSourceTopWithFilters addTarget:screenBlendFilter];
    [screenBlendFilter useNextFrameForImageCapture];

    [stillImageSourceBottom processImage];

    UIImage *mergedlayeredimage = [screenBlendFilter imageFromCurrentFramebuffer];
   [finalImageView setImage:mergedlayeredimage];

Answer 1

嗯，那是因为上面的大多数过滤器实际上并没有做任何事情。您连接的唯一过滤器是 screenBlendFilter，您将源图像都放入其中，然后从中拉出一个图像。您实际上从未将模糊用于那里的任何内容，因此它当然不会影响任何输出。