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