113 lines
3.6 KiB
Objective-C
113 lines
3.6 KiB
Objective-C
#import "GPUImageMotionDetector.h"
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageMotionComparisonFragmentShaderString = 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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uniform highp float intensity;
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void main()
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{
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lowp vec3 currentImageColor = texture2D(inputImageTexture, textureCoordinate).rgb;
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lowp vec3 lowPassImageColor = texture2D(inputImageTexture2, textureCoordinate2).rgb;
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mediump float colorDistance = distance(currentImageColor, lowPassImageColor); // * 0.57735
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lowp float movementThreshold = step(0.2, colorDistance);
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gl_FragColor = movementThreshold * vec4(textureCoordinate2.x, textureCoordinate2.y, 1.0, 1.0);
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}
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);
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#else
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NSString *const kGPUImageMotionComparisonFragmentShaderString = 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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uniform float intensity;
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void main()
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{
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vec3 currentImageColor = texture2D(inputImageTexture, textureCoordinate).rgb;
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vec3 lowPassImageColor = texture2D(inputImageTexture2, textureCoordinate2).rgb;
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float colorDistance = distance(currentImageColor, lowPassImageColor); // * 0.57735
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float movementThreshold = step(0.2, colorDistance);
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gl_FragColor = movementThreshold * vec4(textureCoordinate2.x, textureCoordinate2.y, 1.0, 1.0);
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}
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);
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#endif
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@implementation GPUImageMotionDetector
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@synthesize lowPassFilterStrength, motionDetectionBlock;
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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 = [super init]))
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{
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return nil;
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}
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// Start with a low pass filter to define the component to be removed
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lowPassFilter = [[GPUImageLowPassFilter alloc] init];
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[self addFilter:lowPassFilter];
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// Take the difference of the current frame from the low pass filtered result to get the high pass
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frameComparisonFilter = [[GPUImageTwoInputFilter alloc] initWithFragmentShaderFromString:kGPUImageMotionComparisonFragmentShaderString];
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[self addFilter:frameComparisonFilter];
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// Texture location 0 needs to be the original image for the difference blend
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[lowPassFilter addTarget:frameComparisonFilter atTextureLocation:1];
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// End with the average color for the scene to determine the centroid
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averageColor = [[GPUImageAverageColor alloc] init];
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__unsafe_unretained GPUImageMotionDetector *weakSelf = self;
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[averageColor setColorAverageProcessingFinishedBlock:^(CGFloat redComponent, CGFloat greenComponent, CGFloat blueComponent, CGFloat alphaComponent, CMTime frameTime) {
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if (weakSelf.motionDetectionBlock != NULL)
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{
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weakSelf.motionDetectionBlock(CGPointMake(redComponent / alphaComponent, greenComponent / alphaComponent), alphaComponent, frameTime);
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}
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// NSLog(@"Average X: %f, Y: %f total: %f", redComponent / alphaComponent, greenComponent / alphaComponent, alphaComponent);
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}];
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[frameComparisonFilter addTarget:averageColor];
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self.initialFilters = [NSArray arrayWithObjects:lowPassFilter, frameComparisonFilter, nil];
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self.terminalFilter = frameComparisonFilter;
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self.lowPassFilterStrength = 0.5;
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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)setLowPassFilterStrength:(CGFloat)newValue;
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{
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lowPassFilter.filterStrength = newValue;
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}
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- (CGFloat)lowPassFilterStrength;
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{
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return lowPassFilter.filterStrength;
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}
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@end
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