#import "GPUImageBilateralFilter.h"
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NSString *const kGPUImageBilateralBlurVertexShaderString = SHADER_STRING
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(
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attribute vec4 position;
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attribute vec4 inputTextureCoordinate;
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const int GAUSSIAN_SAMPLES = 9;
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uniform float texelWidthOffset;
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uniform float texelHeightOffset;
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varying vec2 textureCoordinate;
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varying vec2 blurCoordinates[GAUSSIAN_SAMPLES];
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void main()
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{
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gl_Position = position;
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textureCoordinate = inputTextureCoordinate.xy;
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// Calculate the positions for the blur
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int multiplier = 0;
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vec2 blurStep;
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vec2 singleStepOffset = vec2(texelWidthOffset, texelHeightOffset);
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for (int i = 0; i < GAUSSIAN_SAMPLES; i++)
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{
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multiplier = (i - ((GAUSSIAN_SAMPLES - 1) / 2));
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// Blur in x (horizontal)
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blurStep = float(multiplier) * singleStepOffset;
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blurCoordinates[i] = inputTextureCoordinate.xy + blurStep;
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}
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}
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);
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageBilateralFilterFragmentShaderString = SHADER_STRING
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(
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uniform sampler2D inputImageTexture;
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const lowp int GAUSSIAN_SAMPLES = 9;
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varying highp vec2 textureCoordinate;
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varying highp vec2 blurCoordinates[GAUSSIAN_SAMPLES];
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uniform mediump float distanceNormalizationFactor;
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void main()
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{
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lowp vec4 centralColor;
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lowp float gaussianWeightTotal;
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lowp vec4 sum;
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lowp vec4 sampleColor;
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lowp float distanceFromCentralColor;
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lowp float gaussianWeight;
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centralColor = texture2D(inputImageTexture, blurCoordinates[4]);
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gaussianWeightTotal = 0.18;
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sum = centralColor * 0.18;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[0]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.05 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[1]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.09 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[2]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.12 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[3]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.15 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[5]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.15 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[6]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.12 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[7]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.09 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[8]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.05 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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gl_FragColor = sum / gaussianWeightTotal;
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}
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);
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#else
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NSString *const kGPUImageBilateralFilterFragmentShaderString = SHADER_STRING
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(
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uniform sampler2D inputImageTexture;
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const int GAUSSIAN_SAMPLES = 9;
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varying vec2 textureCoordinate;
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varying vec2 blurCoordinates[GAUSSIAN_SAMPLES];
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uniform float distanceNormalizationFactor;
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void main()
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{
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vec4 centralColor;
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float gaussianWeightTotal;
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vec4 sum;
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vec4 sampleColor;
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float distanceFromCentralColor;
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float gaussianWeight;
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centralColor = texture2D(inputImageTexture, blurCoordinates[4]);
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gaussianWeightTotal = 0.18;
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sum = centralColor * 0.18;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[0]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.05 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[1]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.09 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[2]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.12 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[3]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.15 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[5]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.15 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[6]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.12 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[7]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.09 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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sampleColor = texture2D(inputImageTexture, blurCoordinates[8]);
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distanceFromCentralColor = min(distance(centralColor, sampleColor) * distanceNormalizationFactor, 1.0);
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gaussianWeight = 0.05 * (1.0 - distanceFromCentralColor);
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gaussianWeightTotal += gaussianWeight;
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sum += sampleColor * gaussianWeight;
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gl_FragColor = sum / gaussianWeightTotal;
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}
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);
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#endif
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@implementation GPUImageBilateralFilter
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@synthesize distanceNormalizationFactor = _distanceNormalizationFactor;
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- (id)init;
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{
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if (!(self = [super initWithFirstStageVertexShaderFromString:kGPUImageBilateralBlurVertexShaderString
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firstStageFragmentShaderFromString:kGPUImageBilateralFilterFragmentShaderString
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secondStageVertexShaderFromString:kGPUImageBilateralBlurVertexShaderString
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secondStageFragmentShaderFromString:kGPUImageBilateralFilterFragmentShaderString])) {
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return nil;
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}
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firstDistanceNormalizationFactorUniform = [filterProgram uniformIndex:@"distanceNormalizationFactor"];
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secondDistanceNormalizationFactorUniform = [filterProgram uniformIndex:@"distanceNormalizationFactor"];
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self.texelSpacingMultiplier = 4.0;
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self.distanceNormalizationFactor = 8.0;
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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)setDistanceNormalizationFactor:(CGFloat)newValue
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{
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_distanceNormalizationFactor = newValue;
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[self setFloat:newValue
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forUniform:firstDistanceNormalizationFactorUniform
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program:filterProgram];
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[self setFloat:newValue
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forUniform:secondDistanceNormalizationFactorUniform
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program:secondFilterProgram];
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}
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@end
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