IOS OpenGL ES GPUImage 图像阈值边缘检测GPUImageThresholdEdgeDetectionFilter

一.简介
二.效果演示
三.源码下载
四.猜你喜欢

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一.简介

GPUImage 共 125 个滤镜, 分为四类

1、Color adjustments : 31 filters , 颜色处理相关
2、Image processing : 40 filters , 图像处理相关.
3、Blending modes : 29 filters , 混合模式相关.
4、Visual effects : 25 filters , 视觉效果相关.

GPUImageThresholdEdgeDetectionFilter 属于 GPUImage 图像视觉效果相关，用于图像阈值边缘检测。shader 源码如下：

/******************************************************************************************/
//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES GPUImage GPUImageThresholdEdgeDetectionFilter
//@Time:2022/06/26 06:30
//@Motto:不积跬步无以至千里，不积小流无以成江海，程序人生的精彩需要坚持不懈地积累！
/******************************************************************************************/// Invert the colorspace for a sketch
#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImageThresholdEdgeDetectionFragmentShaderString = SHADER_STRING
(precision highp float;varying vec2 textureCoordinate;varying vec2 leftTextureCoordinate;varying vec2 rightTextureCoordinate;varying vec2 topTextureCoordinate;varying vec2 topLeftTextureCoordinate;varying vec2 topRightTextureCoordinate;varying vec2 bottomTextureCoordinate;varying vec2 bottomLeftTextureCoordinate;varying vec2 bottomRightTextureCoordinate;uniform sampler2D inputImageTexture;uniform lowp float threshold;uniform float edgeStrength;void main(){
//     float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
//     float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;
//     float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;
//     float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;float centerIntensity = texture2D(inputImageTexture, textureCoordinate).r;
//     float h = -topLeftIntensity - 2.0 * topIntensity - topRightIntensity + bottomLeftIntensity + 2.0 * bottomIntensity + bottomRightIntensity;
//     float v = -bottomLeftIntensity - 2.0 * leftIntensity - topLeftIntensity + bottomRightIntensity + 2.0 * rightIntensity + topRightIntensity;
//     float h = -topLeftIntensity - 2.0 * topIntensity - topRightIntensity + leftIntensity + 2.0 * centerIntensity + rightIntensity;
//     float v = -bottomLeftIntensity - 2.0 * leftIntensity - topLeftIntensity + bottomIntensity + 2.0 * centerIntensity + topIntensity;float h = (centerIntensity - topIntensity) + (bottomIntensity - centerIntensity);float v = (centerIntensity - leftIntensity) + (rightIntensity - centerIntensity);
//     float h = (centerIntensity - topIntensity);
//     float j = (topIntensity - centerIntensity);
//     h = max(h,j);
//     j = abs(h);
//     float v = (centerIntensity - leftIntensity);float mag = length(vec2(h, v)) * edgeStrength;mag = step(threshold, mag);//     float mag = abs(h);//     gl_FragColor = vec4(h, h, h, 1.0);
//     gl_FragColor = vec4(texture2D(inputImageTexture, textureCoordinate));
//     gl_FragColor = vec4(h, centerIntensity, j, 1.0);gl_FragColor = vec4(mag, mag, mag, 1.0);}
);
#else
NSString *const kGPUImageThresholdEdgeDetectionFragmentShaderString = SHADER_STRING
(varying vec2 textureCoordinate;varying vec2 leftTextureCoordinate;varying vec2 rightTextureCoordinate;varying vec2 topTextureCoordinate;varying vec2 topLeftTextureCoordinate;varying vec2 topRightTextureCoordinate;varying vec2 bottomTextureCoordinate;varying vec2 bottomLeftTextureCoordinate;varying vec2 bottomRightTextureCoordinate;uniform sampler2D inputImageTexture;uniform float threshold;uniform float edgeStrength;void main(){float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;float h = -topLeftIntensity - 2.0 * topIntensity - topRightIntensity + bottomLeftIntensity + 2.0 * bottomIntensity + bottomRightIntensity;h = max(0.0, h);float v = -bottomLeftIntensity - 2.0 * leftIntensity - topLeftIntensity + bottomRightIntensity + 2.0 * rightIntensity + topRightIntensity;v = max(0.0, v);float mag = length(vec2(h, v)) * edgeStrength;mag = step(threshold, mag);gl_FragColor = vec4(vec3(mag), 1.0);}
);
#endif

二.效果演示

使用 GPUImageThresholdEdgeDetectionFilter ****,****原图如下：

使用 GPUImageThresholdEdgeDetectionFilter 效果如下：

三.源码下载

OpenGL ES Demo 下载地址 : IOS OpenGL ES GPUImage 图像阈值边缘检测 GPUImageThresholdEdgeDetectionFilter

四.猜你喜欢

IOS OPenGL ES 设置图像亮度 GPUImageBrightnessFilter
IOS OPenGL ES 调节图像曝光度 GPUImageExposureFilter
IOS OpenGL ES 调节图像对比度 GPUImageContrastFilter
IOS OPenGL ES 调节图像饱和度 GPUImageSaturationFilter
IOS OPenGL ES 调节图像伽马线 GPUImageGammaFilter
IOS OpenGL ES 调节图像反色 GPUImageColorInvertFilter
IOS OpenGL ES 调节图像褐色 GPUImageSepiaFilter
IOS OpenGL ES 调节图像灰色 GPUImageGrayscaleFilter
IOS OpenGL ES 调节图像 RGB 通道 GPUImageRGBFilter
IOS OpenGL ES 调节图像不透明度 GPUImageOpacityFilter
IOS OpenGL ES 调节图像阴影 GPUImageHighlightShadowFilter
IOS OpenGL ES 调节图像色彩替换 GPUImageFalseColorFilter
GPUImage – 色彩直方图 GPUImageHistogramFilter
GPUImage – 色彩直方图 GPUImageHistogramGenerator
GPUImage – 像素平均色值 GPUImageAverageColor
GPUImage – 亮度平均 GPUImageLuminosity
IOS OpenGL ES 调节图像色度 GPUImageHueFilter
IOS OpenGL ES 指定颜色抠图 GPUImageChromaKeyFilter
IOS OpenGL ES 调节图像白平衡/色温 GPUImageWhiteBalanceFilter
IOS OpenGL ES 设置图像 lookup 滤镜 GPUImageLookupFilter
IOS OpenGL ES 设置图像滤镜 GPUImageAmatorkaFilter
IOS OpenGL ES 设置图像滤镜 GPUImageSoftEleganceFilter
IOS OpenGL ES 设置图像锐化 GPUImageSharpenFilter
IOS OpenGL ES 绘制十字 GPUImageCrosshairGenerator
IOS OpenGL ES 绘制线条 GPUImageLineGenerator
IOS OpenGL ES 设置图像黑白燥点 GPUImageLocalBinaryPatternFilter
IOS OpenGL ES 设置图像卡通效果（黑色粗线描边） GPUImageToonFilter
IOS OpenGL ES 桑原滤波/水粉画模糊效果 GPUImageKuwaharaFilter
IOS OpenGL ES 黑白马赛克效果 GPUImageMosaicFilter
IOS OpenGL ES 像素化马赛克效果 GPUImagePixellateFilter
IOS OpenGL ES 同心圆像素化马赛克效果 GPUImagePolarPixel
IOS OpenGL ES 黑白网状效果 GPUImageCrosshatchFilter
IOS OpenGL ES 色彩丢失/模糊效果 GPUImageColorPackingFilter
IOS OpenGL ES 图像晕影 GPUImageVignetteFilter
IOS OpenGL ES 图像漩涡 GPUImageSwirlFilter
IOS OpenGL ES 图像鱼眼扩散效果 GPUImageBulgeDistortionFilter
IOS OpenGL ES 图像鱼眼移动效果 GPUImageBulgeDistortionFilter
IOS OpenGL ES 图像凹面镜移动效果 GPUImagePinchDistortionFilter
IOS OpenGL ES 图像凹面镜放大效果 GPUImagePinchDistortionFilter
IOS OpenGL ES 图像哈哈镜效果 GPUImageStretchDistortionFilter
IOS OpenGL ES 图像水晶球效果 GPUImageGlassSphereFilter
IOS OpenGL ES 图像球形折射 GPUImageSphereRefractionFilter
IOS OpenGL ES 图像色调分离噪点效果 GPUImagePosterizeFilter
IOS OpenGL ES 图像 CGA 色彩滤镜 GPUImageCGAColorspaceFilter
IOS OpenGL ES 图像柏林噪点/花边噪点 GPUImagePerlinNoiseFilter
IOS OpenGL ES 图像加亮边缘 GPUImage3x3ConvolutionFilter
IOS OpenGL ES 图像浮雕 3d 效果 GPUImageEmbossFilter
IOS OpenGL ES 图像马赛克圆点 GPUImagePolkaDotFilter
IOS OpenGL ES 图像侵蚀边缘黑白模糊 GPUImageErosionFilter
IOS OpenGL ES 图像侵蚀边缘色彩模糊 GPUImageRGBErosionFilter
IOS OpenGL ES 图像扩展边缘黑白模糊 GPUImageDilationFilter
IOS OpenGL ES 图像扩展边缘彩色模糊 GPUImageRGBDilationFilter
IOS OpenGL ES GPUImage 黑白色调模糊 GPUImageOpeningFilter
IOS OpenGL ES GPUImage 彩色模糊 GPUImageRGBOpeningFilter
IOS OpenGL ES GPUImage 图像黑白色调模糊/暗色提亮 GPUImageClosingFilter
IOS OpenGL ES GPUImage 图像彩色调模糊/暗色提亮 GPUImageRGBClosingFilter
IOS OpenGL ES GPUImage 图像 Lanczos 重取样模糊效果 GPUImageLanczosResamplingFilter
IOS OpenGL ES GPUImage 图像显示亮度最高的像素,其他为黑 GPUImageNonMaximumSuppressionFilter
IOS OpenGL ES GPUImage 图像显示亮度最高的像素,其他为黑 GPUImageThresholdedNonMaximumSuppressionFilter
IOS OpenGL ES GPUImage 图像 Sobel 边缘检测，类似漫画反色 GPUImageSobelEdgeDetectionFilter
IOS OpenGL ES GPUImage GPUImageWeakPixelInclusionFilter
IOS OpenGL ES GPUImage GPUImageDirectionalNonMaximumSuppressionFilter
IOS OpenGL ES GPUImage 图像阈值边缘检测 GPUImageThresholdEdgeDetectionFilter