#import "GPUImageToonFilter.h"
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#import "GPUImageSobelEdgeDetectionFilter.h"
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#import "GPUImage3x3ConvolutionFilter.h"
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// Code from "Graphics Shaders: Theory and Practice" by M. Bailey and S. Cunningham
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
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NSString *const kGPUImageToonFragmentShaderString = SHADER_STRING
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(
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precision highp float;
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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 sampler2D inputImageTexture;
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uniform highp float intensity;
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uniform highp float threshold;
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uniform highp float quantizationLevels;
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const highp vec3 W = vec3(0.2125, 0.7154, 0.0721);
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void main()
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{
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vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
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float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
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float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;
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float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;
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float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
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float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;
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float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;
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float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;
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float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;
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float h = -topLeftIntensity - 2.0 * topIntensity - topRightIntensity + bottomLeftIntensity + 2.0 * bottomIntensity + bottomRightIntensity;
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float v = -bottomLeftIntensity - 2.0 * leftIntensity - topLeftIntensity + bottomRightIntensity + 2.0 * rightIntensity + topRightIntensity;
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float mag = length(vec2(h, v));
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vec3 posterizedImageColor = floor((textureColor.rgb * quantizationLevels) + 0.5) / quantizationLevels;
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float thresholdTest = 1.0 - step(threshold, mag);
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gl_FragColor = vec4(posterizedImageColor * thresholdTest, textureColor.a);
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}
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);
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#else
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NSString *const kGPUImageToonFragmentShaderString = SHADER_STRING
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(
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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 sampler2D inputImageTexture;
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uniform float intensity;
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uniform float threshold;
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uniform float quantizationLevels;
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const vec3 W = vec3(0.2125, 0.7154, 0.0721);
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void main()
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{
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vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
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float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
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float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;
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float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;
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float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
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float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;
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float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;
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float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;
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float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;
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float h = -topLeftIntensity - 2.0 * topIntensity - topRightIntensity + bottomLeftIntensity + 2.0 * bottomIntensity + bottomRightIntensity;
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float v = -bottomLeftIntensity - 2.0 * leftIntensity - topLeftIntensity + bottomRightIntensity + 2.0 * rightIntensity + topRightIntensity;
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float mag = length(vec2(h, v));
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vec3 posterizedImageColor = floor((textureColor.rgb * quantizationLevels) + 0.5) / quantizationLevels;
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float thresholdTest = 1.0 - step(threshold, mag);
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gl_FragColor = vec4(posterizedImageColor * thresholdTest, textureColor.a);
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}
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);
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#endif
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@implementation GPUImageToonFilter
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@synthesize threshold = _threshold;
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@synthesize quantizationLevels = _quantizationLevels;
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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 initWithFragmentShaderFromString:kGPUImageToonFragmentShaderString]))
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{
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return nil;
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}
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hasOverriddenImageSizeFactor = NO;
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thresholdUniform = [filterProgram uniformIndex:@"threshold"];
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quantizationLevelsUniform = [filterProgram uniformIndex:@"quantizationLevels"];
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self.threshold = 0.2;
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self.quantizationLevels = 10.0;
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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)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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- (void)setQuantizationLevels:(CGFloat)newValue;
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{
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_quantizationLevels = newValue;
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[self setFloat:_quantizationLevels forUniform:quantizationLevelsUniform program:filterProgram];
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}
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@end
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