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Reworked the box blur in the same fashion as the new Gaussian blur, s…
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…o it is now truly smooth across various radii.
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@BradLarson
BradLarson committed Oct 19, 2013
1 parent 4fc4cfa commit 619ea47
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Showing 8 changed files with 262 additions and 129 deletions.
27 changes: 26 additions & 1 deletion examples/iOS/FeatureExtractionTest/FeatureExtractionTest/FeatureExtractionAppDelegate.m
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Expand Up @@ -119,6 +119,12 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
CIContext *coreImageContext = [CIContext contextWithEAGLContext:[[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]];

// CIContext *coreImageContext = [CIContext contextWithOptions:nil];

// NSArray *cifilters = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];
// for (NSString *ciFilterName in cifilters)
// {
// NSLog(@"%@", ciFilterName);
// }
CIImage *inputCIGaussianImage = [[CIImage alloc] initWithCGImage:gaussianBlurInput.CGImage];
CIFilter *gaussianBlurCIFilter = [CIFilter filterWithName:@"CIGaussianBlur"
keysAndValues: kCIInputImageKey, inputCIGaussianImage,
Expand All @@ -127,8 +133,27 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
CGImageRef resultRef = [coreImageContext createCGImage:coreImageResult fromRect:CGRectMake(0, 0, gaussianBlurInput.size.width, gaussianBlurInput.size.height)];
UIImage *coreImageResult2 = [UIImage imageWithCGImage:resultRef];
[self saveImage:coreImageResult2 fileName:@"Gaussian-CoreImage.png"];

CGImageRelease(resultRef);

GPUImageBoxBlurFilter *boxBlur = [[GPUImageBoxBlurFilter alloc] init];
boxBlur.blurRadiusInPixels = 3.0;
[gaussianImage removeAllTargets];
[gaussianImage addTarget:boxBlur];
[gaussianImage processImage];
UIImage *boxOutput = [boxBlur imageFromCurrentlyProcessedOutput];
[self saveImage:boxOutput fileName:@"BoxBlur-GPUImage.png"];

CIImage *inputCIBoxImage = [[CIImage alloc] initWithCGImage:gaussianBlurInput.CGImage];
CIFilter *boxBlurCIFilter = [CIFilter filterWithName:@"CIBoxBlur"
keysAndValues: kCIInputImageKey, inputCIBoxImage,
@"inputRadius", [NSNumber numberWithFloat:2.0], nil];

NSLog(@"Box blur: %@", boxBlurCIFilter);
CIImage *coreImageResult3 = [boxBlurCIFilter outputImage];
CGImageRef resultRef2 = [coreImageContext createCGImage:coreImageResult3 fromRect:CGRectMake(0, 0, gaussianBlurInput.size.width, gaussianBlurInput.size.height)];
UIImage *coreImageResult4 = [UIImage imageWithCGImage:resultRef2];
[self saveImage:coreImageResult4 fileName:@"BoxBlur-CoreImage.png"];
CGImageRelease(resultRef2);

[chairPicture removeAllTargets];
[chairPicture addTarget:averageColor];
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9 changes: 7 additions & 2 deletions examples/iOS/FilterShowcase/FilterShowcase/ShowcaseFilterViewController.m
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Original file line number Diff line number Diff line change
Expand Up @@ -1154,15 +1154,19 @@ - (void)setupFilter;
self.filterSettingsSlider.hidden = NO;

[self.filterSettingsSlider setMinimumValue:1.0];
[self.filterSettingsSlider setMaximumValue:14.0];
[self.filterSettingsSlider setMaximumValue:24.0];
[self.filterSettingsSlider setValue:2.0];

filter = [[GPUImageGaussianBlurFilter alloc] init];
}; break;
case GPUIMAGE_BOXBLUR:
{
self.title = @"Box Blur";
self.filterSettingsSlider.hidden = YES;
self.filterSettingsSlider.hidden = NO;

[self.filterSettingsSlider setMinimumValue:1.0];
[self.filterSettingsSlider setMaximumValue:24.0];
[self.filterSettingsSlider setValue:2.0];

filter = [[GPUImageBoxBlurFilter alloc] init];
}; break;
Expand Down Expand Up @@ -1589,6 +1593,7 @@ - (IBAction)updateFilterFromSlider:(id)sender;
case GPUIMAGE_PERLINNOISE: [(GPUImagePerlinNoiseFilter *)filter setScale:[(UISlider *)sender value]]; break;
case GPUIMAGE_MOSAIC: [(GPUImageMosaicFilter *)filter setDisplayTileSize:CGSizeMake([(UISlider *)sender value], [(UISlider *)sender value])]; break;
case GPUIMAGE_VIGNETTE: [(GPUImageVignetteFilter *)filter setVignetteEnd:[(UISlider *)sender value]]; break;
case GPUIMAGE_BOXBLUR: [(GPUImageBoxBlurFilter *)filter setBlurRadiusInPixels:[(UISlider*)sender value]]; break;
case GPUIMAGE_GAUSSIAN: [(GPUImageGaussianBlurFilter *)filter setBlurRadiusInPixels:[(UISlider*)sender value]]; break;
// case GPUIMAGE_GAUSSIAN: [(GPUImageGaussianBlurFilter *)filter setBlurPasses:round([(UISlider*)sender value])]; break;
// case GPUIMAGE_BILATERAL: [(GPUImageBilateralFilter *)filter setBlurSize:[(UISlider*)sender value]]; break;
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37 changes: 35 additions & 2 deletions framework/Source/GPUImageBilateralFilter.m
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Original file line number Diff line number Diff line change
@@ -1,5 +1,38 @@
#import "GPUImageBilateralFilter.h"

NSString *const kGPUImageBilateralBlurVertexShaderString = SHADER_STRING
(
attribute vec4 position;
attribute vec4 inputTextureCoordinate;

const int GAUSSIAN_SAMPLES = 9;

uniform float texelWidthOffset;
uniform float texelHeightOffset;

varying vec2 textureCoordinate;
varying vec2 blurCoordinates[GAUSSIAN_SAMPLES];

void main()
{
gl_Position = position;
textureCoordinate = inputTextureCoordinate.xy;

// Calculate the positions for the blur
int multiplier = 0;
vec2 blurStep;
vec2 singleStepOffset = vec2(texelWidthOffset, texelHeightOffset);

for (int i = 0; i < GAUSSIAN_SAMPLES; i++)
{
multiplier = (i - ((GAUSSIAN_SAMPLES - 1) / 2));
// Blur in x (horizontal)
blurStep = float(multiplier) * singleStepOffset;
blurCoordinates[i] = inputTextureCoordinate.xy + blurStep;
}
}
);

#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImageBilateralFilterFragmentShaderString = SHADER_STRING
(
Expand Down Expand Up @@ -161,9 +194,9 @@ @implementation GPUImageBilateralFilter
- (id)init;
{

if (!(self = [super initWithFirstStageVertexShaderFromString:nil
if (!(self = [super initWithFirstStageVertexShaderFromString:kGPUImageBilateralBlurVertexShaderString
firstStageFragmentShaderFromString:kGPUImageBilateralFilterFragmentShaderString
secondStageVertexShaderFromString:nil
secondStageVertexShaderFromString:kGPUImageBilateralBlurVertexShaderString
secondStageFragmentShaderFromString:kGPUImageBilateralFilterFragmentShaderString])) {
return nil;
}
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9 changes: 3 additions & 6 deletions framework/Source/GPUImageBoxBlurFilter.h
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Original file line number Diff line number Diff line change
@@ -1,10 +1,7 @@
#import "GPUImageTwoPassTextureSamplingFilter.h"
#import "GPUImageGaussianBlurFilter.h"

/** A hardware-accelerated 9-hit box blur of an image
/** A hardware-accelerated box blur of an image
*/
@interface GPUImageBoxBlurFilter : GPUImageTwoPassTextureSamplingFilter

/// A scaling for the size of the applied blur, default of 1.0
@property(readwrite, nonatomic) CGFloat blurSize;
@interface GPUImageBoxBlurFilter : GPUImageGaussianBlurFilter

@end
225 changes: 143 additions & 82 deletions framework/Source/GPUImageBoxBlurFilter.m
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Original file line number Diff line number Diff line change
@@ -1,112 +1,173 @@
#import "GPUImageBoxBlurFilter.h"

NSString *const kGPUImageBoxBlurVertexShaderString = SHADER_STRING
(
attribute vec4 position;
attribute vec2 inputTextureCoordinate;

uniform float texelWidthOffset;
uniform float texelHeightOffset;
@implementation GPUImageBoxBlurFilter

varying vec2 centerTextureCoordinate;
varying vec2 oneStepLeftTextureCoordinate;
varying vec2 twoStepsLeftTextureCoordinate;
varying vec2 oneStepRightTextureCoordinate;
varying vec2 twoStepsRightTextureCoordinate;
+ (NSString *)vertexShaderForOptimizedBlurOfRadius:(NSUInteger)blurRadius sigma:(CGFloat)sigma;
{
if (blurRadius == 0)
{
return nil;
}

void main()
{
gl_Position = position;

vec2 firstOffset = vec2(1.5 * texelWidthOffset, 1.5 * texelHeightOffset);
vec2 secondOffset = vec2(3.5 * texelWidthOffset, 3.5 * texelHeightOffset);

centerTextureCoordinate = inputTextureCoordinate;
oneStepLeftTextureCoordinate = inputTextureCoordinate - firstOffset;
twoStepsLeftTextureCoordinate = inputTextureCoordinate - secondOffset;
oneStepRightTextureCoordinate = inputTextureCoordinate + firstOffset;
twoStepsRightTextureCoordinate = inputTextureCoordinate + secondOffset;
}
);
// From these weights we calculate the offsets to read interpolated values from
NSUInteger numberOfOptimizedOffsets = MIN(blurRadius / 2 + (blurRadius % 2), 7);

NSMutableString *shaderString = [[NSMutableString alloc] init];
// Header
[shaderString appendFormat:@"\
attribute vec4 position;\n\
attribute vec4 inputTextureCoordinate;\n\
\n\
uniform float texelWidthOffset;\n\
uniform float texelHeightOffset;\n\
\n\
varying vec2 blurCoordinates[%d];\n\
\n\
void main()\n\
{\n\
gl_Position = position;\n\
\n\
vec2 singleStepOffset = vec2(texelWidthOffset, texelHeightOffset);\n", 1 + (numberOfOptimizedOffsets * 2)];

// Inner offset loop
[shaderString appendString:@"blurCoordinates[0] = inputTextureCoordinate.xy;\n"];
for (NSUInteger currentOptimizedOffset = 0; currentOptimizedOffset < numberOfOptimizedOffsets; currentOptimizedOffset++)
{
GLfloat optimizedOffset = (GLfloat)(currentOptimizedOffset * 2) + 1.5;

[shaderString appendFormat:@"\
blurCoordinates[%d] = inputTextureCoordinate.xy + singleStepOffset * %f;\n\
blurCoordinates[%d] = inputTextureCoordinate.xy - singleStepOffset * %f;\n", (currentOptimizedOffset * 2) + 1, optimizedOffset, (currentOptimizedOffset * 2) + 2, optimizedOffset];
}

// Footer
[shaderString appendString:@"}\n"];

#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImageBoxBlurFragmentShaderString = SHADER_STRING
(
precision highp float;
return shaderString;
}

uniform sampler2D inputImageTexture;

varying vec2 centerTextureCoordinate;
varying vec2 oneStepLeftTextureCoordinate;
varying vec2 twoStepsLeftTextureCoordinate;
varying vec2 oneStepRightTextureCoordinate;
varying vec2 twoStepsRightTextureCoordinate;

void main()
{
lowp vec4 fragmentColor = texture2D(inputImageTexture, centerTextureCoordinate) * 0.2;
fragmentColor += texture2D(inputImageTexture, oneStepLeftTextureCoordinate) * 0.2;
fragmentColor += texture2D(inputImageTexture, oneStepRightTextureCoordinate) * 0.2;
fragmentColor += texture2D(inputImageTexture, twoStepsLeftTextureCoordinate) * 0.2;
fragmentColor += texture2D(inputImageTexture, twoStepsRightTextureCoordinate) * 0.2;

gl_FragColor = fragmentColor;
}
);
+ (NSString *)fragmentShaderForOptimizedBlurOfRadius:(NSUInteger)blurRadius sigma:(CGFloat)sigma;
{
if (blurRadius == 0)
{
return nil;
}

NSUInteger numberOfOptimizedOffsets = MIN(blurRadius / 2 + (blurRadius % 2), 7);
NSUInteger trueNumberOfOptimizedOffsets = blurRadius / 2 + (blurRadius % 2);

NSMutableString *shaderString = [[NSMutableString alloc] init];

// Header
#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
[shaderString appendFormat:@"\
uniform sampler2D inputImageTexture;\n\
uniform highp float texelWidthOffset;\n\
uniform highp float texelHeightOffset;\n\
\n\
varying highp vec2 blurCoordinates[%d];\n\
\n\
void main()\n\
{\n\
lowp vec4 sum = vec4(0.0);\n", 1 + (numberOfOptimizedOffsets * 2) ];
#else
NSString *const kGPUImageBoxBlurFragmentShaderString = SHADER_STRING
(
uniform sampler2D inputImageTexture;

varying vec2 centerTextureCoordinate;
varying vec2 oneStepLeftTextureCoordinate;
varying vec2 twoStepsLeftTextureCoordinate;
varying vec2 oneStepRightTextureCoordinate;
varying vec2 twoStepsRightTextureCoordinate;

void main()
{
vec4 fragmentColor = texture2D(inputImageTexture, centerTextureCoordinate) * 0.2;
fragmentColor += texture2D(inputImageTexture, oneStepLeftTextureCoordinate) * 0.2;
fragmentColor += texture2D(inputImageTexture, oneStepRightTextureCoordinate) * 0.2;
fragmentColor += texture2D(inputImageTexture, twoStepsLeftTextureCoordinate) * 0.2;
fragmentColor += texture2D(inputImageTexture, twoStepsRightTextureCoordinate) * 0.2;

gl_FragColor = fragmentColor;
}
);
[shaderString appendFormat:@"\
uniform sampler2D inputImageTexture;\n\
uniform float texelWidthOffset;\n\
uniform float texelHeightOffset;\n\
\n\
varying vec2 blurCoordinates[%d];\n\
\n\
void main()\n\
{\n\
vec4 sum = vec4(0.0);\n", 1 + (numberOfOptimizedOffsets * 2) ];
#endif

GLfloat boxWeight = 1.0 / (GLfloat)((blurRadius * 2) + 1);

// Inner texture loop
[shaderString appendFormat:@"sum += texture2D(inputImageTexture, blurCoordinates[0]) * %f;\n", boxWeight];

for (NSUInteger currentBlurCoordinateIndex = 0; currentBlurCoordinateIndex < numberOfOptimizedOffsets; currentBlurCoordinateIndex++)
{
[shaderString appendFormat:@"sum += texture2D(inputImageTexture, blurCoordinates[%d]) * %f;\n", (currentBlurCoordinateIndex * 2) + 1, boxWeight * 2.0];
[shaderString appendFormat:@"sum += texture2D(inputImageTexture, blurCoordinates[%d]) * %f;\n", (currentBlurCoordinateIndex * 2) + 2, boxWeight * 2.0];
}

// If the number of required samples exceeds the amount we can pass in via varyings, we have to do dependent texture reads in the fragment shader
if (trueNumberOfOptimizedOffsets > numberOfOptimizedOffsets)
{
[shaderString appendString:@"highp vec2 singleStepOffset = vec2(texelWidthOffset, texelHeightOffset);\n"];

for (NSUInteger currentOverlowTextureRead = numberOfOptimizedOffsets; currentOverlowTextureRead < trueNumberOfOptimizedOffsets; currentOverlowTextureRead++)
{
GLfloat optimizedOffset = (GLfloat)(currentOverlowTextureRead * 2) + 1.5;

[shaderString appendFormat:@"sum += texture2D(inputImageTexture, blurCoordinates[0] + singleStepOffset * %f) * %f;\n", optimizedOffset, boxWeight * 2.0];
[shaderString appendFormat:@"sum += texture2D(inputImageTexture, blurCoordinates[0] - singleStepOffset * %f) * %f;\n", optimizedOffset, boxWeight * 2.0];
}
}

// Footer
[shaderString appendString:@"\
gl_FragColor = sum;\n\
}\n"];

return shaderString;
}

@implementation GPUImageBoxBlurFilter

@synthesize blurSize = _blurSize;
- (void)setupFilterForSize:(CGSize)filterFrameSize;
{
[super setupFilterForSize:filterFrameSize];

if (shouldResizeBlurRadiusWithImageSize == YES)
{

}
}

#pragma mark -
#pragma mark Initialization and teardown

- (id)init;
{
if (!(self = [super initWithFirstStageVertexShaderFromString:kGPUImageBoxBlurVertexShaderString firstStageFragmentShaderFromString:kGPUImageBoxBlurFragmentShaderString secondStageVertexShaderFromString:kGPUImageBoxBlurVertexShaderString secondStageFragmentShaderFromString:kGPUImageBoxBlurFragmentShaderString]))
// NSString *currentGaussianBlurVertexShader = [GPUImageGaussianBlurFilter vertexShaderForStandardGaussianOfRadius:4 sigma:2.0];
// NSString *currentGaussianBlurFragmentShader = [GPUImageGaussianBlurFilter fragmentShaderForStandardGaussianOfRadius:4 sigma:2.0];

NSString *currentBoxBlurVertexShader = [[self class] vertexShaderForOptimizedBlurOfRadius:4 sigma:0.0];
NSString *currentBoxBlurFragmentShader = [[self class] fragmentShaderForOptimizedBlurOfRadius:4 sigma:0.0];

if (!(self = [super initWithFirstStageVertexShaderFromString:currentBoxBlurVertexShader firstStageFragmentShaderFromString:currentBoxBlurFragmentShader secondStageVertexShaderFromString:currentBoxBlurVertexShader secondStageFragmentShaderFromString:currentBoxBlurFragmentShader]))
{
return nil;
return nil;
}

self.blurSize = 1.0;
_blurRadiusInPixels = 4.0;

return self;
}

#pragma mark -
#pragma mark Accessors

- (void)setBlurSize:(CGFloat)newValue;
- (void)setBlurRadiusInPixels:(CGFloat)newValue;
{
_blurSize = newValue;

_verticalTexelSpacing = _blurSize;
_horizontalTexelSpacing = _blurSize;
CGFloat newBlurRadius = round(round(newValue / 2.0) * 2.0); // For now, only do even radii

[self setupFilterForSize:[self sizeOfFBO]];
if (newBlurRadius != _blurRadiusInPixels)
{
_blurRadiusInPixels = newBlurRadius;

NSString *newGaussianBlurVertexShader = [[self class] vertexShaderForOptimizedBlurOfRadius:_blurRadiusInPixels sigma:0.0];
NSString *newGaussianBlurFragmentShader = [[self class] fragmentShaderForOptimizedBlurOfRadius:_blurRadiusInPixels sigma:0.0];

// NSLog(@"Optimized vertex shader: \n%@", newGaussianBlurVertexShader);
// NSLog(@"Optimized fragment shader: \n%@", newGaussianBlurFragmentShader);
//
[self switchToVertexShader:newGaussianBlurVertexShader fragmentShader:newGaussianBlurFragmentShader];
}
shouldResizeBlurRadiusWithImageSize = NO;
}

@end
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