GPUImage中曝光滤镜实现——GPUImageExposureFilter

核心代码：

 varying highp vec2 textureCoordinate;
 
 uniform sampler2D inputImageTexture;
 uniform highp float exposure;
 
 void main()
 {
     highp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
     
     gl_FragColor = vec4(textureColor.rgb * pow(2.0, exposure), textureColor.w);
 }

其中exposure的取值范围为[-10,10]

https://github.com/BradLarson/GPUImage