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GPUImage教程(一)安装,使用例子, 原理和内置滤镜列表

2016年05月25日 ⁄ 综合 ⁄ 共 9571字 ⁄ 字号 小 中 大 ⁄ 评论关闭
第一部分: 安装
一. 安装: Adding
the framework to your iOS project

1. 把GPUImage.xcodeproj
拖到你的Xcode project
2. 在app的target依赖设置里面添加GPUImage作为Target
Dependency
3. 在build phase的Link
Binary With Libraries, 把libGPUImage.a加进来.
4. 添加下面这些系统framework:
  • CoreMedia
  • CoreVideo
  • OpenGLES
  • AVFoundation
  • QuartzCore


5. 头文件搜索路径: project's
build settings, 把GPUImage的source和source下的iOS目录加到搜索路径里, 使用相对路径和递归.
6. 包含下面这个头文件:
  1. #import "GPUImage.h"

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二. 静态库方法

Building static library at the command line

If you don't
want to include the project as a dependency in your application's Xcode project, you can build a universal static library for the iOS Simulator or device. To do this, run build.sh at the command line. The resulting library and header files will be located
at build/Release-iphone. You may also change the version of the iOS SDK by changing the IOSSDK_VER variable in build.sh (all available versions can be found using xcodebuild -showsdks).


第二部分: 使用
一. Filtering
live video
  1. GPUImageVideoCamera *videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack];
  2. videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;

  4. GPUImageFilter *customFilter = [[GPUImageFilter alloc] initWithFragmentShaderFromFile:@"CustomShader"];
  5. GPUImageView *filteredVideoView = [[GPUImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, viewWidth, viewHeight)];

  7. // Add the view somewhere so it's visible

  9. [videoCamera addTarget:customFilter];
  10. [customFilter addTarget:filteredVideoView];

  12. [videoCamera startCameraCapture];

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1. 首先建立一个outputs,
对video情况是video source:  videoCamera,  采用背部主相机, 已经预设的(preset) 640x480, 并采用portrait模式, 如果是landscape left下拍摄的,需要自己旋转一下来显示.
2. 建立一个filter,
customFilter, 并设置为video source的target.
3. 建立一个显示view,
并设置为filter的target.  可以设置显示view的fillMode
4. 开始action: 
 [videoCamera startCameraCapture];

从 outputs ->
filter -> display view 是一个 filter chain,  如果有多个outputs进行混合(blend), 把他们的target都设成相同的filter就可以了.
如果要是记录电影的话:可以使用下面这句进行声音捕捉.

  1. videoCamera.audioEncodingTarget = movieWriter;

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二. Capturing
and filtering a still photo
相机预览代码:  (此时虽然是相机模式, 仍然会给出一个still camera的预览视频)
  1. stillCamera = [[GPUImageStillCamera alloc] init];
  2. stillCamera.outputImageOrientation = UIInterfaceOrientationPortrait;

  4. filter = [[GPUImageGammaFilter alloc] init];
  5. [stillCamera addTarget:filter];
  6. GPUImageView *filterView = (GPUImageView *)self.view;
  7. [filter addTarget:filterView];

  9. [stillCamera startCameraCapture];

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拍照代码:
  1. [stillCamera capturePhotoProcessedUpToFilter:filter withCompletionHandler:^(UIImage *processedImage, NSError *error){
  2.     NSData *dataForPNGFile = UIImageJPEGRepresentation(processedImage, 0.8);

  4.     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  5.     NSString *documentsDirectory = [paths objectAtIndex:0];

  7.     NSError *error2 = nil;
  8.     if (![dataForPNGFile writeToFile:[documentsDirectory stringByAppendingPathComponent:@"FilteredPhoto.jpg"] options:NSAtomicWrite error:&error2])
  9.     {
  10.         return;
  11.     }
  12. }];

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三. Processing
a still image
  1. UIImage *inputImage = [UIImage imageNamed:@"Lambeau.jpg"];

  3. GPUImagePicture *stillImageSource = [[GPUImagePicture alloc] initWithImage:inputImage];
  4. GPUImageSepiaFilter *stillImageFilter = [[GPUImageSepiaFilter alloc] init];

  6. [stillImageSource addTarget:stillImageFilter];
  7. [stillImageSource processImage];

  9. UIImage *currentFilteredVideoFrame = [stillImageFilter imageFromCurrentlyProcessedOutput];

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一个filter下更简单的方法:
  1. GPUImageSepiaFilter *stillImageFilter2 = [[GPUImageSepiaFilter alloc] init];
  2. UIImage *quickFilteredImage = [stillImageFilter2 imageByFilteringImage:inputImage];

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四. 自定义滤镜


从bundle里面加载OpenGL
Shading Language编写的 fragment shader文件, 后缀是 .fsh  或者从字符串里面加载.
  1. GPUImageFilter *customFilter = [[GPUImageFilter alloc] initWithFragmentShaderFromFile:@"CustomShader"];

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  1. NSString *const kfilterShader = SHADER_STRING
  2. (
  3. ...
  4. );

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一个脚本的例子:
  1. varying highp vec2 textureCoordinate;

  3. uniform sampler2D inputImageTexture;

  5. void main()
  6. {
  7.     lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
  8.     lowp vec4 outputColor;
  9.     outputColor.r = (textureColor.r * 0.393) + (textureColor.g * 0.769) + (textureColor.b * 0.189);
  10.     outputColor.g = (textureColor.r * 0.349) + (textureColor.g * 0.686) + (textureColor.b * 0.168);    
  11.     outputColor.b = (textureColor.r * 0.272) + (textureColor.g * 0.534) + (textureColor.b * 0.131);
  12.     outputColor.a = 1.0;

  14.     gl_FragColor = outputColor;
  15. }

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这段脚本有一个varing,
表示的是材质的2D坐标, 一个unifrom是材质的图片.
main函数里面把这个坐标的颜色取出来处理后生成新的颜色,
交给gl_FragColor传递个pipeline的下一个单元. 在这里也就是最终输出.

五. Filtering
and re-encoding a movie
  1. movieFile = [[GPUImageMovie alloc] initWithURL:sampleURL];
  2. pixellateFilter = [[GPUImagePixellateFilter alloc] init];

  4. [movieFile addTarget:pixellateFilter];

  6. NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Movie.m4v"];
  7. unlink([pathToMovie UTF8String]);
  8. NSURL *movieURL = [NSURL fileURLWithPath:pathToMovie];

  10. movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(480.0, 640.0)];
  11. [pixellateFilter addTarget:movieWriter];

  13. movieWriter.shouldPassthroughAudio = YES;
  14. movieFile.audioEncodingTarget = movieWriter;
  15. [movieFile enableSynchronizedEncodingUsingMovieWriter:movieWriter];

  17. [movieWriter startRecording];
  18. [movieFile startProcessing];

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GPUImageMovie作为源,
中间是filter, 最终是GPUImageMovieWriter来写入文件.  这段代码是输出480 x 640 h.264 movie
GPUImageMovieWriter非常快,
能够实时的保存iPhone 4的640x480到输出文件, 在iPhone4上, 720p能20fps的速度输出, iPhone 4S上720p 和 1080p都能达到30 FPS


结束的时候停止代码:
  1. [pixellateFilter removeTarget:movieWriter];
  2. [movieWriter finishRecording];

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如果不停止, 输出文件不可用,
如果中间被打断, 输出文件会丢失.


六. Interacting
with OpenGL ES


GPUImage使用GPUImageTextureOutput
和 GPUImageTextureInput 想Open GL ES 2.0输出或者输入材质, 可用把GPUImage的输出作为OpenGL的材质输入, 或者把OpenGL的输出作为自己的材质输入.
例子代码正在整理中



第三部分, 原理


GPUImage是一个链(chain),     source -> phase1 target -> phase2 target -> final target


第一个环节是source, 这是一些GPUImageOutput的子类.包括:
(1). GPUImageVideoCamera (for live video from an iOS camera)
(2.) GPUImageStillCamera (for taking photos with the camera)
(3). GPUImagePicture (for still images) 
(4). GPUImageMovie (for movies). S


后续环节是被称为target.  遵循GPUImageInput protocol

可用多个source到一个target上面进行blend,  也可用进行分支, 添加多个target.


一般的target可分为两类

(1)中间环节的target,  一般是各种filter, 是GPUImageFilter或者是子类.
(2)最终环节的target, 可用是GPUImageView, 或者GPUImageMovieWriter


一个典型的例子

  1. GPUImageVideoCamera -> GPUImageSepiaFilter -> GPUImageView

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第四部分, 内置滤镜列表



共125个滤镜, 分为四类

Color adjustments:  31 filters, 颜色处理相关

Image processing:   40 filters, 图像处理相关.

Blending modes:     29 filters,  混合模式相关.

Visual effects:     25 filters,  视觉效果相关.



下面分别列出车125个滤镜的名字, 后续再对每个专题进行讲解.


Color adjustments:  31 filters

    GPUImageBrightnessFilter

    GPUImageExposureFilter

    GPUImageContrastFilter

    GPUImageSaturationFilter

    GPUImageGammaFilter

    GPUImageLevelsFilter

    GPUImageColorMatrixFilter

    GPUImageRGBFilter

    GPUImageHueFilter

    GPUImageToneCurveFilter


    GPUImageHighlightShadowFilter


    GPUImageLookupFilter

    GPUImageAmatorkaFilter

    GPUImageMissEtikateFilter

    GPUImageSoftEleganceFilter


    GPUImageColorInvertFilter

    GPUImageGrayscaleFilter

    GPUImageMonochromeFilter

    GPUImageFalseColorFilter


    GPUImageHazeFilter


    GPUImageSepiaFilter

    GPUImageOpacityFilter

    GPUImageSolidColorGenerator


    GPUImageLuminanceThresholdFilter

    GPUImageAdaptiveThresholdFilter

    GPUImageAverageLuminanceThresholdFilter

    GPUImageHistogramFilter

    GPUImageHistogramGenerator

    GPUImageAverageColor

    GPUImageLuminosity


    GPUImageChromaKeyFilter 



Image processing:  40 filters

    GPUImageTransformFilter

    GPUImageCropFilter

    GPUImageLanczosResamplingFilter

    GPUImageSharpenFilter

    GPUImageUnsharpMaskFilter

    GPUImageGaussianBlurFilter

    GPUImageBoxBlurFilter

    GPUImageSingleComponentGaussianBlurFilter

    GPUImageGaussianSelectiveBlurFilter

    GPUImageGaussianBlurPositionFilter

    GPUImageiOSBlurFilter

    GPUImageMedianFilter

    GPUImageBilateralFilter

    GPUImageTiltShiftFilter

    GPUImage3x3ConvolutionFilter

    GPUImageSobelEdgeDetectionFilter

    GPUImagePrewittEdgeDetectionFilter

    GPUImageThresholdEdgeDetectionFilter

    GPUImageCannyEdgeDetectionFilter

    GPUImageHarrisCornerDetectionFilter

    GPUImageNobleCornerDetectionFilter

    GPUImageShiTomasiCornerDetectionFilter

    GPUImageNonMaximumSuppressionFilter

    GPUImageXYDerivativeFilter

    GPUImageCrosshairGenerator

    GPUImageDilationFilter

    GPUImageRGBDilationFilter

    GPUImageErosionFilter

    GPUImageRGBErosionFilter

    GPUImageOpeningFilter

    GPUImageRGBOpeningFilter

    GPUImageClosingFilter

    GPUImageRGBClosingFilter

    GPUImageLocalBinaryPatternFilter

    GPUImageLowPassFilter

    GPUImageHighPassFilter

    GPUImageMotionDetector

    GPUImageHoughTransformLineDetector

    GPUImageLineGenerator

    GPUImageMotionBlurFilter


Blending modes: 29 filters

    GPUImageZoomBlurFilter

    GPUImageChromaKeyBlendFilter

    GPUImageDissolveBlendFilter

    GPUImageMultiplyBlendFilter

    GPUImageAddBlendFilter

    GPUImageSubtractBlendFilter

    GPUImageDivideBlendFilter

    GPUImageOverlayBlendFilter

    GPUImageDarkenBlendFilter

    GPUImageLightenBlendFilter

    GPUImageColorBurnBlendFilter

    GPUImageColorDodgeBlendFilter

    GPUImageScreenBlendFilter

    GPUImageExclusionBlendFilter

    GPUImageDifferenceBlendFilter

    GPUImageHardLightBlendFilter

    GPUImageSoftLightBlendFilter

    GPUImageAlphaBlendFilter

    GPUImageSourceOverBlendFilter

    GPUImageColorBurnBlendFilter

    GPUImageColorDodgeBlendFilter

    GPUImageNormalBlendFilter

    GPUImageColorBlendFilter

    GPUImageHueBlendFilter

    GPUImageSaturationBlendFilter

    GPUImageLuminosityBlendFilter

    GPUImageLinearBurnBlendFilter

    GPUImagePoissonBlendFilter

    GPUImageMaskFilter


Visual effects: 25 filters

    GPUImagePixellateFilter

    GPUImagePolarPixellateFilter

    GPUImagePolkaDotFilter

    GPUImageHalftoneFilter

    GPUImageCrosshatchFilter

    GPUImageSketchFilter

    GPUImageThresholdSketchFilter

    GPUImageToonFilter

    GPUImageSmoothToonFilter

    GPUImageEmbossFilter

    GPUImagePosterizeFilter

    GPUImageSwirlFilter

    GPUImageBulgeDistortionFilter

    GPUImagePinchDistortionFilter

    GPUImageStretchDistortionFilter

    GPUImageSphereRefractionFilter

    GPUImageGlassSphereFilter

    GPUImageVignetteFilter

    GPUImageKuwaharaFilter

    GPUImageKuwaharaRadius3Filter

    GPUImagePerlinNoiseFilter

    GPUImageCGAColorspaceFilter

    GPUImageMosaicFilter

    GPUImageJFAVoronoiFilter

    GPUImageVoronoiConsumerFilter
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