#import "GPUImageSphereRefractionFilter.h"
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageSphereRefractionFragmentShaderString = SHADER_STRING
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(
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varying highp vec2 textureCoordinate;
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uniform sampler2D inputImageTexture;
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uniform highp vec2 center;
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uniform highp float radius;
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uniform highp float aspectRatio;
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uniform highp float refractiveIndex;
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void main()
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{
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highp vec2 textureCoordinateToUse = vec2(textureCoordinate.x, (textureCoordinate.y * aspectRatio + 0.5 - 0.5 * aspectRatio));
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highp float distanceFromCenter = distance(center, textureCoordinateToUse);
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lowp float checkForPresenceWithinSphere = step(distanceFromCenter, radius);
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distanceFromCenter = distanceFromCenter / radius;
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highp float normalizedDepth = radius * sqrt(1.0 - distanceFromCenter * distanceFromCenter);
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highp vec3 sphereNormal = normalize(vec3(textureCoordinateToUse - center, normalizedDepth));
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highp vec3 refractedVector = refract(vec3(0.0, 0.0, -1.0), sphereNormal, refractiveIndex);
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gl_FragColor = texture2D(inputImageTexture, (refractedVector.xy + 1.0) * 0.5) * checkForPresenceWithinSphere;
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}
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);
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#else
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NSString *const kGPUImageSphereRefractionFragmentShaderString = SHADER_STRING
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(
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varying vec2 textureCoordinate;
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uniform sampler2D inputImageTexture;
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uniform vec2 center;
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uniform float radius;
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uniform float aspectRatio;
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uniform float refractiveIndex;
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void main()
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{
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vec2 textureCoordinateToUse = vec2(textureCoordinate.x, (textureCoordinate.y * aspectRatio + 0.5 - 0.5 * aspectRatio));
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float distanceFromCenter = distance(center, textureCoordinateToUse);
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float checkForPresenceWithinSphere = step(distanceFromCenter, radius);
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distanceFromCenter = distanceFromCenter / radius;
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float normalizedDepth = radius * sqrt(1.0 - distanceFromCenter * distanceFromCenter);
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vec3 sphereNormal = normalize(vec3(textureCoordinateToUse - center, normalizedDepth));
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vec3 refractedVector = refract(vec3(0.0, 0.0, -1.0), sphereNormal, refractiveIndex);
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gl_FragColor = texture2D(inputImageTexture, (refractedVector.xy + 1.0) * 0.5) * checkForPresenceWithinSphere;
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}
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);
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#endif
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@interface GPUImageSphereRefractionFilter ()
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- (void)adjustAspectRatio;
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@property (readwrite, nonatomic) CGFloat aspectRatio;
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@end
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@implementation GPUImageSphereRefractionFilter
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@synthesize center = _center;
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@synthesize radius = _radius;
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@synthesize aspectRatio = _aspectRatio;
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@synthesize refractiveIndex = _refractiveIndex;
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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 initWithFragmentShaderFromString:kGPUImageSphereRefractionFragmentShaderString]))
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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)initWithFragmentShaderFromString:(NSString *)fragmentShaderString;
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{
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if (!(self = [super initWithFragmentShaderFromString:fragmentShaderString]))
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{
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return nil;
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}
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radiusUniform = [filterProgram uniformIndex:@"radius"];
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aspectRatioUniform = [filterProgram uniformIndex:@"aspectRatio"];
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centerUniform = [filterProgram uniformIndex:@"center"];
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refractiveIndexUniform = [filterProgram uniformIndex:@"refractiveIndex"];
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self.radius = 0.25;
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self.center = CGPointMake(0.5, 0.5);
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self.refractiveIndex = 0.71;
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[self setBackgroundColorRed:0.0 green:0.0 blue:0.0 alpha:0.0];
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return self;
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}
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- (void)setInputSize:(CGSize)newSize atIndex:(NSInteger)textureIndex;
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{
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CGSize oldInputSize = inputTextureSize;
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[super setInputSize:newSize atIndex:textureIndex];
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if (!CGSizeEqualToSize(oldInputSize, inputTextureSize) && (!CGSizeEqualToSize(newSize, CGSizeZero)) )
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{
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[self adjustAspectRatio];
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}
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}
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#pragma mark -
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#pragma mark Accessors
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- (void)adjustAspectRatio;
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{
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if (GPUImageRotationSwapsWidthAndHeight(inputRotation))
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{
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[self setAspectRatio:(inputTextureSize.width / inputTextureSize.height)];
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}
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else
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{
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[self setAspectRatio:(inputTextureSize.height / inputTextureSize.width)];
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}
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}
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- (void)setInputRotation:(GPUImageRotationMode)newInputRotation atIndex:(NSInteger)textureIndex;
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{
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[super setInputRotation:newInputRotation atIndex:textureIndex];
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[self setCenter:self.center];
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[self adjustAspectRatio];
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}
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- (void)forceProcessingAtSize:(CGSize)frameSize;
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{
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[super forceProcessingAtSize:frameSize];
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[self adjustAspectRatio];
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}
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- (void)setRadius:(CGFloat)newValue;
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{
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_radius = newValue;
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[self setFloat:_radius forUniform:radiusUniform program:filterProgram];
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}
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- (void)setCenter:(CGPoint)newValue;
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{
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_center = newValue;
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CGPoint rotatedPoint = [self rotatedPoint:_center forRotation:inputRotation];
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[self setPoint:rotatedPoint forUniform:centerUniform program:filterProgram];
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}
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- (void)setAspectRatio:(CGFloat)newValue;
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{
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_aspectRatio = newValue;
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[self setFloat:_aspectRatio forUniform:aspectRatioUniform program:filterProgram];
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}
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- (void)setRefractiveIndex:(CGFloat)newValue;
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{
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_refractiveIndex = newValue;
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[self setFloat:_refractiveIndex forUniform:refractiveIndexUniform program:filterProgram];
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}
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@end
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