IOS – OpenGL ES 設置圖像黑白噪點 GPUImageLocalBinaryPatternFilter

目錄一.簡介二.效果演示三.源碼下載四.猜你喜歡零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 基礎零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 轉場零基礎 O ...

一.簡介
二.效果演示
三.源碼下載
四.猜你喜歡

零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 基礎

零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 轉場

零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 特效

零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 函數

零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES GPUImage 使用

零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES GLSL 編程

一.簡介

GPUImage 共 125 個濾鏡, 分為四類

1、Color adjustments : 31 filters , 顏色處理相關
2、Image processing : 40 filters , 圖像處理相關.
3、Blending modes : 29 filters , 混合模式相關.
4、Visual effects : 25 filters , 視覺效果相關.

GPUImageLocalBinaryPatternFilter 屬於 GPUImage 圖像處理相關，用來圖像黑白化，並有大量噪點，shader 源碼如下：

/******************************************************************************************/
//@Author:猿說編程
//@Blog(個人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES 設置圖像黑白化 ，並有大量噪點GPUImageLocalBinaryPatternFilter
//@Time:2022/04/20 07:30
//@Motto:不積跬步無以至千里，不積小流無以成江海，程式人生的精彩需要堅持不懈地積累！
/******************************************************************************************/


#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 individually

     gl_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 individually

     gl_FragColor = vec4(byteTally, byteTally, byteTally, 1.0);
 }
);
#endif