#import "GPUImageThresholdedNonMaximumSuppressionFilter.h"
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageThresholdedNonMaximumSuppressionFragmentShaderString = SHADER_STRING
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(
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uniform sampler2D inputImageTexture;
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varying highp vec2 textureCoordinate;
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varying highp vec2 leftTextureCoordinate;
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varying highp vec2 rightTextureCoordinate;
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varying highp vec2 topTextureCoordinate;
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varying highp vec2 topLeftTextureCoordinate;
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varying highp vec2 topRightTextureCoordinate;
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varying highp vec2 bottomTextureCoordinate;
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varying highp vec2 bottomLeftTextureCoordinate;
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varying highp vec2 bottomRightTextureCoordinate;
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uniform lowp float threshold;
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void main()
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{
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lowp float bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate).r;
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lowp float bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
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lowp float bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
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lowp vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);
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lowp float leftColor = texture2D(inputImageTexture, leftTextureCoordinate).r;
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lowp float rightColor = texture2D(inputImageTexture, rightTextureCoordinate).r;
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lowp float topColor = texture2D(inputImageTexture, topTextureCoordinate).r;
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lowp float topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate).r;
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lowp float topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate).r;
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// Use a tiebreaker for pixels to the left and immediately above this one
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lowp float multiplier = 1.0 - step(centerColor.r, topColor);
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multiplier = multiplier * (1.0 - step(centerColor.r, topLeftColor));
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multiplier = multiplier * (1.0 - step(centerColor.r, leftColor));
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multiplier = multiplier * (1.0 - step(centerColor.r, bottomLeftColor));
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lowp float maxValue = max(centerColor.r, bottomColor);
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maxValue = max(maxValue, bottomRightColor);
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maxValue = max(maxValue, rightColor);
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maxValue = max(maxValue, topRightColor);
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lowp float finalValue = centerColor.r * step(maxValue, centerColor.r) * multiplier;
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finalValue = step(threshold, finalValue);
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gl_FragColor = vec4(finalValue, finalValue, finalValue, 1.0);
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//
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// gl_FragColor = vec4((centerColor.rgb * step(maxValue, step(threshold, centerColor.r)) * multiplier), 1.0);
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}
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);
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NSString *const kGPUImageThresholdedNonMaximumSuppressionPackedColorspaceFragmentShaderString = SHADER_STRING
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(
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uniform sampler2D inputImageTexture;
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varying highp vec2 textureCoordinate;
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varying highp vec2 leftTextureCoordinate;
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varying highp vec2 rightTextureCoordinate;
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varying highp vec2 topTextureCoordinate;
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varying highp vec2 topLeftTextureCoordinate;
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varying highp vec2 topRightTextureCoordinate;
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varying highp vec2 bottomTextureCoordinate;
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varying highp vec2 bottomLeftTextureCoordinate;
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varying highp vec2 bottomRightTextureCoordinate;
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uniform lowp float threshold;
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uniform highp float texelWidth;
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uniform highp float texelHeight;
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highp float encodedIntensity(highp vec3 sourceColor)
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{
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return (sourceColor.b * 256.0 * 256.0 + sourceColor.g * 256.0 + sourceColor.r);
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}
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void main()
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{
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highp float bottomColor = encodedIntensity(texture2D(inputImageTexture, bottomTextureCoordinate).rgb);
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highp float bottomLeftColor = encodedIntensity(texture2D(inputImageTexture, bottomLeftTextureCoordinate).rgb);
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highp float bottomRightColor = encodedIntensity(texture2D(inputImageTexture, bottomRightTextureCoordinate).rgb);
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highp float centerColor = encodedIntensity(texture2D(inputImageTexture, textureCoordinate).rgb);
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highp float leftColor = encodedIntensity(texture2D(inputImageTexture, leftTextureCoordinate).rgb);
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highp float rightColor = encodedIntensity(texture2D(inputImageTexture, rightTextureCoordinate).rgb);
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highp float topColor = encodedIntensity(texture2D(inputImageTexture, topTextureCoordinate).rgb);
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highp float topRightColor = encodedIntensity(texture2D(inputImageTexture, topRightTextureCoordinate).rgb);
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highp float topLeftColor = encodedIntensity(texture2D(inputImageTexture, topLeftTextureCoordinate).rgb);
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highp float secondStageColor1 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, -2.0 * texelHeight)).rgb);
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highp float secondStageColor2 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, -1.0 * texelHeight)).rgb);
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highp float secondStageColor3 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, 0.0)).rgb);
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highp float secondStageColor4 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, 1.0 * texelHeight)).rgb);
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highp float secondStageColor5 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, 2.0 * texelHeight)).rgb);
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highp float secondStageColor6 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-1.0 * texelWidth, 2.0 * texelHeight)).rgb);
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highp float secondStageColor7 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(0.0, 2.0 * texelHeight)).rgb);
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highp float secondStageColor8 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(1.0 * texelWidth, 2.0 * texelHeight)).rgb);
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highp float thirdStageColor1 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-1.0 * texelWidth, -2.0 * texelHeight)).rgb);
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highp float thirdStageColor2 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(0.0, -2.0 * texelHeight)).rgb);
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highp float thirdStageColor3 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(1.0 * texelWidth, -2.0 * texelHeight)).rgb);
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highp float thirdStageColor4 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, -2.0 * texelHeight)).rgb);
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highp float thirdStageColor5 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, -1.0 * texelHeight)).rgb);
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highp float thirdStageColor6 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, 0.0)).rgb);
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highp float thirdStageColor7 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, 1.0 * texelHeight)).rgb);
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highp float thirdStageColor8 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, 2.0 * texelHeight)).rgb);
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// Use a tiebreaker for pixels to the left and immediately above this one
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highp float multiplier = 1.0 - step(centerColor, topColor);
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multiplier = multiplier * (1.0 - step(centerColor, topLeftColor));
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multiplier = multiplier * (1.0 - step(centerColor, leftColor));
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multiplier = multiplier * (1.0 - step(centerColor, bottomLeftColor));
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multiplier = multiplier * (1.0 - step(centerColor, secondStageColor1));
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multiplier = multiplier * (1.0 - step(centerColor, secondStageColor2));
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multiplier = multiplier * (1.0 - step(centerColor, secondStageColor3));
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multiplier = multiplier * (1.0 - step(centerColor, secondStageColor4));
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multiplier = multiplier * (1.0 - step(centerColor, secondStageColor5));
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multiplier = multiplier * (1.0 - step(centerColor, secondStageColor6));
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multiplier = multiplier * (1.0 - step(centerColor, secondStageColor7));
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multiplier = multiplier * (1.0 - step(centerColor, secondStageColor8));
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highp float maxValue = max(centerColor, bottomColor);
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maxValue = max(maxValue, bottomRightColor);
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maxValue = max(maxValue, rightColor);
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maxValue = max(maxValue, topRightColor);
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maxValue = max(maxValue, thirdStageColor1);
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maxValue = max(maxValue, thirdStageColor2);
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maxValue = max(maxValue, thirdStageColor3);
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maxValue = max(maxValue, thirdStageColor4);
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maxValue = max(maxValue, thirdStageColor5);
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maxValue = max(maxValue, thirdStageColor6);
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maxValue = max(maxValue, thirdStageColor7);
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maxValue = max(maxValue, thirdStageColor8);
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highp float midValue = centerColor * step(maxValue, centerColor) * multiplier;
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highp float finalValue = step(threshold, midValue);
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gl_FragColor = vec4(finalValue * centerColor, topLeftColor, topRightColor, topColor);
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}
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);
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#else
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NSString *const kGPUImageThresholdedNonMaximumSuppressionFragmentShaderString = SHADER_STRING
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(
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uniform sampler2D inputImageTexture;
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varying vec2 textureCoordinate;
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varying vec2 leftTextureCoordinate;
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varying vec2 rightTextureCoordinate;
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varying vec2 topTextureCoordinate;
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varying vec2 topLeftTextureCoordinate;
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varying vec2 topRightTextureCoordinate;
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varying vec2 bottomTextureCoordinate;
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varying vec2 bottomLeftTextureCoordinate;
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varying vec2 bottomRightTextureCoordinate;
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uniform float threshold;
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void main()
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{
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float bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate).r;
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float bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
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float bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
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vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);
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float leftColor = texture2D(inputImageTexture, leftTextureCoordinate).r;
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float rightColor = texture2D(inputImageTexture, rightTextureCoordinate).r;
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float topColor = texture2D(inputImageTexture, topTextureCoordinate).r;
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float topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate).r;
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float topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate).r;
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// Use a tiebreaker for pixels to the left and immediately above this one
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float multiplier = 1.0 - step(centerColor.r, topColor);
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multiplier = multiplier * (1.0 - step(centerColor.r, topLeftColor));
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multiplier = multiplier * (1.0 - step(centerColor.r, leftColor));
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multiplier = multiplier * (1.0 - step(centerColor.r, bottomLeftColor));
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float maxValue = max(centerColor.r, bottomColor);
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maxValue = max(maxValue, bottomRightColor);
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maxValue = max(maxValue, rightColor);
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maxValue = max(maxValue, topRightColor);
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float finalValue = centerColor.r * step(maxValue, centerColor.r) * multiplier;
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finalValue = step(threshold, finalValue);
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gl_FragColor = vec4(finalValue, finalValue, finalValue, 1.0);
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//
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// gl_FragColor = vec4((centerColor.rgb * step(maxValue, step(threshold, centerColor.r)) * multiplier), 1.0);
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}
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);
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NSString *const kGPUImageThresholdedNonMaximumSuppressionPackedColorspaceFragmentShaderString = SHADER_STRING
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(
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uniform sampler2D inputImageTexture;
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varying vec2 textureCoordinate;
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varying vec2 leftTextureCoordinate;
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varying vec2 rightTextureCoordinate;
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varying vec2 topTextureCoordinate;
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varying vec2 topLeftTextureCoordinate;
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varying vec2 topRightTextureCoordinate;
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varying vec2 bottomTextureCoordinate;
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varying vec2 bottomLeftTextureCoordinate;
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varying vec2 bottomRightTextureCoordinate;
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uniform float threshold;
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void main()
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{
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float bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate).r;
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float bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
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float bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
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vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);
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float leftColor = texture2D(inputImageTexture, leftTextureCoordinate).r;
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float rightColor = texture2D(inputImageTexture, rightTextureCoordinate).r;
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float topColor = texture2D(inputImageTexture, topTextureCoordinate).r;
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float topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate).r;
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float topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate).r;
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// Use a tiebreaker for pixels to the left and immediately above this one
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float multiplier = 1.0 - step(centerColor.r, topColor);
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multiplier = multiplier * (1.0 - step(centerColor.r, topLeftColor));
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multiplier = multiplier * (1.0 - step(centerColor.r, leftColor));
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multiplier = multiplier * (1.0 - step(centerColor.r, bottomLeftColor));
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float maxValue = max(centerColor.r, bottomColor);
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maxValue = max(maxValue, bottomRightColor);
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maxValue = max(maxValue, rightColor);
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maxValue = max(maxValue, topRightColor);
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float finalValue = centerColor.r * step(maxValue, centerColor.r) * multiplier;
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finalValue = step(threshold, finalValue);
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gl_FragColor = vec4(finalValue, finalValue, finalValue, 1.0);
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//
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// gl_FragColor = vec4((centerColor.rgb * step(maxValue, step(threshold, centerColor.r)) * multiplier), 1.0);
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}
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);
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#endif
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@implementation GPUImageThresholdedNonMaximumSuppressionFilter
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@synthesize threshold = _threshold;
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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 = [self initWithPackedColorspace:NO]))
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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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- (id)initWithPackedColorspace:(BOOL)inputUsesPackedColorspace;
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{
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NSString *shaderString;
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if (inputUsesPackedColorspace)
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{
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shaderString = kGPUImageThresholdedNonMaximumSuppressionPackedColorspaceFragmentShaderString;
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}
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else
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{
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shaderString = kGPUImageThresholdedNonMaximumSuppressionFragmentShaderString;
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}
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if (!(self = [super initWithFragmentShaderFromString:shaderString]))
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{
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return nil;
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}
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thresholdUniform = [filterProgram uniformIndex:@"threshold"];
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self.threshold = 0.9;
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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)setThreshold:(CGFloat)newValue;
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{
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_threshold = newValue;
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[self setFloat:_threshold forUniform:thresholdUniform program:filterProgram];
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}
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@end
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