IOS – OpenGL ES 调节图像色彩替换 GPUImageFalseColorFilter

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//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES 调节图像色彩替换 GPUImageFalseColorFilter
//@Time:2022/03/19 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！
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUFalseColorFragmentShaderString = SHADER_STRING
(
 precision lowp float;

 varying highp vec2 textureCoordinate;

 uniform sampler2D inputImageTexture;
 uniform float intensity;
 uniform vec3 firstColor;
 uniform vec3 secondColor;

 const mediump vec3 luminanceWeighting = vec3(0.2125, 0.7154, 0.0721);

 void main()
 {
     lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
     float luminance = dot(textureColor.rgb, luminanceWeighting);

     gl_FragColor = vec4( mix(firstColor.rgb, secondColor.rgb, luminance), textureColor.a);
 }
);
#else
NSString *const kGPUFalseColorFragmentShaderString = SHADER_STRING
(
 varying vec2 textureCoordinate;

 uniform sampler2D inputImageTexture;
 uniform float intensity;
 uniform vec3 firstColor;
 uniform vec3 secondColor;

 const vec3 luminanceWeighting = vec3(0.2125, 0.7154, 0.0721);

 void main()
 {
     vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
     float luminance = dot(textureColor.rgb, luminanceWeighting);

     gl_FragColor = vec4( mix(firstColor.rgb, secondColor.rgb, luminance), textureColor.a);
 }
);
#endif