#import "GPUImageGammaFilter.h"
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageGammaFragmentShaderString = SHADER_STRING
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(
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varying highp vec2 textureCoordinate;
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uniform sampler2D inputImageTexture;
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uniform lowp float gamma;
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void main()
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{
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lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
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gl_FragColor = vec4(pow(textureColor.rgb, vec3(gamma)), textureColor.w);
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}
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);
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#else
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NSString *const kGPUImageGammaFragmentShaderString = SHADER_STRING
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(
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varying vec2 textureCoordinate;
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uniform sampler2D inputImageTexture;
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uniform float gamma;
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void main()
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{
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vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
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gl_FragColor = vec4(pow(textureColor.rgb, vec3(gamma)), textureColor.w);
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}
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);
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#endif
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@implementation GPUImageGammaFilter
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@synthesize gamma = _gamma;
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#pragma mark -
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#pragma mark Initialization and teardown
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- (id)init;
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{
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if (!(self = [super initWithFragmentShaderFromString:kGPUImageGammaFragmentShaderString]))
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{
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return nil;
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}
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gammaUniform = [filterProgram uniformIndex:@"gamma"];
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self.gamma = 1.0;
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return self;
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}
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#pragma mark -
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#pragma mark Accessors
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- (void)setGamma:(CGFloat)newValue;
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{
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_gamma = newValue;
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[self setFloat:_gamma forUniform:gammaUniform program:filterProgram];
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}
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@end
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