#import "GPUImageExclusionBlendFilter.h"
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageExclusionBlendFragmentShaderString = SHADER_STRING
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(
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varying highp vec2 textureCoordinate;
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varying highp vec2 textureCoordinate2;
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uniform sampler2D inputImageTexture;
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uniform sampler2D inputImageTexture2;
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void main()
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{
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mediump vec4 base = texture2D(inputImageTexture, textureCoordinate);
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mediump vec4 overlay = texture2D(inputImageTexture2, textureCoordinate2);
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// Dca = (Sca.Da + Dca.Sa - 2.Sca.Dca) + Sca.(1 - Da) + Dca.(1 - Sa)
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gl_FragColor = vec4((overlay.rgb * base.a + base.rgb * overlay.a - 2.0 * overlay.rgb * base.rgb) + overlay.rgb * (1.0 - base.a) + base.rgb * (1.0 - overlay.a), base.a);
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}
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);
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#else
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NSString *const kGPUImageExclusionBlendFragmentShaderString = SHADER_STRING
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(
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varying vec2 textureCoordinate;
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varying vec2 textureCoordinate2;
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uniform sampler2D inputImageTexture;
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uniform sampler2D inputImageTexture2;
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void main()
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{
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vec4 base = texture2D(inputImageTexture, textureCoordinate);
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vec4 overlay = texture2D(inputImageTexture2, textureCoordinate2);
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// Dca = (Sca.Da + Dca.Sa - 2.Sca.Dca) + Sca.(1 - Da) + Dca.(1 - Sa)
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gl_FragColor = vec4((overlay.rgb * base.a + base.rgb * overlay.a - 2.0 * overlay.rgb * base.rgb) + overlay.rgb * (1.0 - base.a) + base.rgb * (1.0 - overlay.a), base.a);
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}
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);
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#endif
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@implementation GPUImageExclusionBlendFilter
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- (id)init;
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{
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if (!(self = [super initWithFragmentShaderFromString:kGPUImageExclusionBlendFragmentShaderString]))
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{
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return nil;
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}
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return self;
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}
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@end
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