#import "GPUImageDivideBlendFilter.h"
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageDivideBlendFragmentShaderString = 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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mediump float ra;
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if (overlay.a == 0.0 || ((base.r / overlay.r) > (base.a / overlay.a)))
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ra = overlay.a * base.a + overlay.r * (1.0 - base.a) + base.r * (1.0 - overlay.a);
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else
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ra = (base.r * overlay.a * overlay.a) / overlay.r + overlay.r * (1.0 - base.a) + base.r * (1.0 - overlay.a);
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mediump float ga;
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if (overlay.a == 0.0 || ((base.g / overlay.g) > (base.a / overlay.a)))
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ga = overlay.a * base.a + overlay.g * (1.0 - base.a) + base.g * (1.0 - overlay.a);
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else
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ga = (base.g * overlay.a * overlay.a) / overlay.g + overlay.g * (1.0 - base.a) + base.g * (1.0 - overlay.a);
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mediump float ba;
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if (overlay.a == 0.0 || ((base.b / overlay.b) > (base.a / overlay.a)))
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ba = overlay.a * base.a + overlay.b * (1.0 - base.a) + base.b * (1.0 - overlay.a);
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else
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ba = (base.b * overlay.a * overlay.a) / overlay.b + overlay.b * (1.0 - base.a) + base.b * (1.0 - overlay.a);
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mediump float a = overlay.a + base.a - overlay.a * base.a;
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gl_FragColor = vec4(ra, ga, ba, a);
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}
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);
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#else
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NSString *const kGPUImageDivideBlendFragmentShaderString = 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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float ra;
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if (overlay.a == 0.0 || ((base.r / overlay.r) > (base.a / overlay.a)))
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ra = overlay.a * base.a + overlay.r * (1.0 - base.a) + base.r * (1.0 - overlay.a);
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else
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ra = (base.r * overlay.a * overlay.a) / overlay.r + overlay.r * (1.0 - base.a) + base.r * (1.0 - overlay.a);
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float ga;
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if (overlay.a == 0.0 || ((base.g / overlay.g) > (base.a / overlay.a)))
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ga = overlay.a * base.a + overlay.g * (1.0 - base.a) + base.g * (1.0 - overlay.a);
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else
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ga = (base.g * overlay.a * overlay.a) / overlay.g + overlay.g * (1.0 - base.a) + base.g * (1.0 - overlay.a);
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float ba;
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if (overlay.a == 0.0 || ((base.b / overlay.b) > (base.a / overlay.a)))
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ba = overlay.a * base.a + overlay.b * (1.0 - base.a) + base.b * (1.0 - overlay.a);
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else
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ba = (base.b * overlay.a * overlay.a) / overlay.b + overlay.b * (1.0 - base.a) + base.b * (1.0 - overlay.a);
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float a = overlay.a + base.a - overlay.a * base.a;
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gl_FragColor = vec4(ra, ga, ba, a);
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}
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);
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#endif
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@implementation GPUImageDivideBlendFilter
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- (id)init;
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{
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if (!(self = [super initWithFragmentShaderFromString:kGPUImageDivideBlendFragmentShaderString]))
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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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