GPUImage – 亮度平均 GPUImageLuminosity

目錄

• 一.簡介
• 二.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.

GPUImageLuminosity 屬於 GPUImage 顏色處理相關，用來處理圖片亮度平均，像 [GPUImageAverageColor](https://www.codersrc.com/archives/15617.html) 一樣，將圖像縮小到其平均亮度。

/******************************************************************************************/
//@Author:猿說編程
//@Blog(個人博客地址): www.codersrc.com
//@File:GPUImage – 亮度平均 GPUImageLuminosity
//@Time:2022/03/25 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 kGPUImageInitialLuminosityFragmentShaderString = SHADER_STRING
(
 precision highp float;
 
 uniform sampler2D inputImageTexture;
 
 varying highp vec2 outputTextureCoordinate;
 
 varying highp vec2 upperLeftInputTextureCoordinate;
 varying highp vec2 upperRightInputTextureCoordinate;
 varying highp vec2 lowerLeftInputTextureCoordinate;
 varying highp vec2 lowerRightInputTextureCoordinate;
 
 const highp vec3 W = vec3(0.2125, 0.7154, 0.0721);

 void main()
 {
     highp float upperLeftLuminance = dot(texture2D(inputImageTexture, upperLeftInputTextureCoordinate).rgb, W);
     highp float upperRightLuminance = dot(texture2D(inputImageTexture, upperRightInputTextureCoordinate).rgb, W);
     highp float lowerLeftLuminance = dot(texture2D(inputImageTexture, lowerLeftInputTextureCoordinate).rgb, W);
     highp float lowerRightLuminance = dot(texture2D(inputImageTexture, lowerRightInputTextureCoordinate).rgb, W);

     highp float luminosity = 0.25 * (upperLeftLuminance + upperRightLuminance + lowerLeftLuminance + lowerRightLuminance);
     gl_FragColor = vec4(luminosity, luminosity, luminosity, 1.0);
 }
);

NSString *const kGPUImageLuminosityFragmentShaderString = SHADER_STRING
(
 precision highp float;
 
 uniform sampler2D inputImageTexture;
 
 varying highp vec2 outputTextureCoordinate;
 
 varying highp vec2 upperLeftInputTextureCoordinate;
 varying highp vec2 upperRightInputTextureCoordinate;
 varying highp vec2 lowerLeftInputTextureCoordinate;
 varying highp vec2 lowerRightInputTextureCoordinate;
 
 void main()
 {
     highp float upperLeftLuminance = texture2D(inputImageTexture, upperLeftInputTextureCoordinate).r;
     highp float upperRightLuminance = texture2D(inputImageTexture, upperRightInputTextureCoordinate).r;
     highp float lowerLeftLuminance = texture2D(inputImageTexture, lowerLeftInputTextureCoordinate).r;
     highp float lowerRightLuminance = texture2D(inputImageTexture, lowerRightInputTextureCoordinate).r;
     
     highp float luminosity = 0.25 * (upperLeftLuminance + upperRightLuminance + lowerLeftLuminance + lowerRightLuminance);
     gl_FragColor = vec4(luminosity, luminosity, luminosity, 1.0);
 }
);
#else
NSString *const kGPUImageInitialLuminosityFragmentShaderString = SHADER_STRING
(
 uniform sampler2D inputImageTexture;
 
 varying vec2 outputTextureCoordinate;
 
 varying vec2 upperLeftInputTextureCoordinate;
 varying vec2 upperRightInputTextureCoordinate;
 varying vec2 lowerLeftInputTextureCoordinate;
 varying vec2 lowerRightInputTextureCoordinate;
 
 const vec3 W = vec3(0.2125, 0.7154, 0.0721);
 
 void main()
 {
     float upperLeftLuminance = dot(texture2D(inputImageTexture, upperLeftInputTextureCoordinate).rgb, W);
     float upperRightLuminance = dot(texture2D(inputImageTexture, upperRightInputTextureCoordinate).rgb, W);
     float lowerLeftLuminance = dot(texture2D(inputImageTexture, lowerLeftInputTextureCoordinate).rgb, W);
     float lowerRightLuminance = dot(texture2D(inputImageTexture, lowerRightInputTextureCoordinate).rgb, W);
     
     float luminosity = 0.25 * (upperLeftLuminance + upperRightLuminance + lowerLeftLuminance + lowerRightLuminance);
     gl_FragColor = vec4(luminosity, luminosity, luminosity, 1.0);
 }
);

NSString *const kGPUImageLuminosityFragmentShaderString = SHADER_STRING
(
 uniform sampler2D inputImageTexture;
 
 varying vec2 outputTextureCoordinate;
 
 varying vec2 upperLeftInputTextureCoordinate;
 varying vec2 upperRightInputTextureCoordinate;
 varying vec2 lowerLeftInputTextureCoordinate;
 varying vec2 lowerRightInputTextureCoordinate;
 
 void main()
 {
     float upperLeftLuminance = texture2D(inputImageTexture, upperLeftInputTextureCoordinate).r;
     float upperRightLuminance = texture2D(inputImageTexture, upperRightInputTextureCoordinate).r;
     float lowerLeftLuminance = texture2D(inputImageTexture, lowerLeftInputTextureCoordinate).r;
     float lowerRightLuminance = texture2D(inputImageTexture, lowerRightInputTextureCoordinate).r;
     
     float luminosity = 0.25 * (upperLeftLuminance + upperRightLuminance + lowerLeftLuminance + lowerRightLuminance);
     gl_FragColor = vec4(luminosity, luminosity, luminosity, 1.0);
 }
);
#endif

二.猜你喜歡

• IOS – OPenGL ES 設置圖像亮度 GPUImageBrightnessFilter
• IOS – OPenGL ES 調節圖像曝光度 GPUImageExposureFilter
• IOS – OpenGL ES 調節圖像對比度 GPUImageContrastFilter
• IOS – OPenGL ES 調節圖像飽和度 GPUImageSaturationFilter
• IOS – OPenGL ES 調節圖像伽馬線 GPUImageGammaFilter
• IOS – OpenGL ES 調節圖像反色 GPUImageColorInvertFilter
• IOS – OpenGL ES 調節圖像褐色 GPUImageSepiaFilter
• IOS – OpenGL ES 調節圖像灰色 GPUImageGrayscaleFilter
• IOS – OpenGL ES 調節圖像RGB通道 GPUImageRGBFilter
• IOS – OpenGL ES 調節圖像不透明度 GPUImageOpacityFilter
• IOS – OpenGL ES 調節圖像陰影 GPUImageHighlightShadowFilter
• IOS – OpenGL ES 調節圖像色彩替換 GPUImageFalseColorFilter
• GPUImage – 色彩直方圖 GPUImageHistogramFilter
• GPUImage – 色彩直方圖 GPUImageHistogramGenerator
• GPUImage – 像素平均色值 GPUImageAverageColor
• GPUImage – 亮度平均 GPUImageLuminosity

本文由博客 - 猿說編程 猿說編程 發佈！