/******************************************************************************************/
//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES 设置图像黑白化 ，并有大量噪点GPUImageLocalBinaryPatternFilter
//@Time:2022/04/20 07:30
//@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！
/******************************************************************************************/#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImageLocalBinaryPatternFragmentShaderString = 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;void main(){lowp float centerIntensity = texture2D(inputImageTexture, textureCoordinate).r;lowp float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;lowp float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;lowp float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;lowp float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;lowp float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;lowp float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;lowp float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;lowp float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;lowp float byteTally = 1.0 / 255.0 * step(centerIntensity, topRightIntensity);byteTally += 2.0 / 255.0 * step(centerIntensity, topIntensity);byteTally += 4.0 / 255.0 * step(centerIntensity, topLeftIntensity);byteTally += 8.0 / 255.0 * step(centerIntensity, leftIntensity);byteTally += 16.0 / 255.0 * step(centerIntensity, bottomLeftIntensity);byteTally += 32.0 / 255.0 * step(centerIntensity, bottomIntensity);byteTally += 64.0 / 255.0 * step(centerIntensity, bottomRightIntensity);byteTally += 128.0 / 255.0 * step(centerIntensity, rightIntensity);// TODO: Replace the above with a dot product and two vec4s// TODO: Apply step to a matrix, rather than individuallygl_FragColor = vec4(byteTally, byteTally, byteTally, 1.0);}
);
#else
NSString *const kGPUImageLocalBinaryPatternFragmentShaderString = 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;void main(){float centerIntensity = texture2D(inputImageTexture, textureCoordinate).r;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 byteTally = 1.0 / 255.0 * step(centerIntensity, topRightIntensity);byteTally += 2.0 / 255.0 * step(centerIntensity, topIntensity);byteTally += 4.0 / 255.0 * step(centerIntensity, topLeftIntensity);byteTally += 8.0 / 255.0 * step(centerIntensity, leftIntensity);byteTally += 16.0 / 255.0 * step(centerIntensity, bottomLeftIntensity);byteTally += 32.0 / 255.0 * step(centerIntensity, bottomIntensity);byteTally += 64.0 / 255.0 * step(centerIntensity, bottomRightIntensity);byteTally += 128.0 / 255.0 * step(centerIntensity, rightIntensity);// TODO: Replace the above with a dot product and two vec4s// TODO: Apply step to a matrix, rather than individuallygl_FragColor = vec4(byteTally, byteTally, byteTally, 1.0);}
);
#endif

**GPUImageLocalBinaryPatternFilter **图像黑白化**，效果图：**