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#import "GPUImage3x3ConvolutionFilter.h"
#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImage3x3ConvolutionFragmentShaderString = SHADER_STRING
(
precision highp float;
uniform sampler2D inputImageTexture;
uniform mediump mat3 convolutionMatrix;
varying vec2 textureCoordinate;
varying vec2 leftTextureCoordinate;
varying vec2 rightTextureCoordinate;
varying vec2 topTextureCoordinate;
varying vec2 topLeftTextureCoordinate;
varying vec2 topRightTextureCoordinate;
varying vec2 bottomTextureCoordinate;
varying vec2 bottomLeftTextureCoordinate;
varying vec2 bottomRightTextureCoordinate;
void main()
{
mediump vec3 bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate).rgb;
mediump vec3 bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate).rgb;
mediump vec3 bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate).rgb;
mediump vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);
mediump vec3 leftColor = texture2D(inputImageTexture, leftTextureCoordinate).rgb;
mediump vec3 rightColor = texture2D(inputImageTexture, rightTextureCoordinate).rgb;
mediump vec3 topColor = texture2D(inputImageTexture, topTextureCoordinate).rgb;
mediump vec3 topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate).rgb;
mediump vec3 topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate).rgb;
mediump vec3 resultColor = topLeftColor * convolutionMatrix[0][0] + topColor * convolutionMatrix[0][1] + topRightColor * convolutionMatrix[0][2];
resultColor += leftColor * convolutionMatrix[1][0] + centerColor.rgb * convolutionMatrix[1][1] + rightColor * convolutionMatrix[1][2];
resultColor += bottomLeftColor * convolutionMatrix[2][0] + bottomColor * convolutionMatrix[2][1] + bottomRightColor * convolutionMatrix[2][2];
gl_FragColor = vec4(resultColor, centerColor.a);
}
);
#else
NSString *const kGPUImage3x3ConvolutionFragmentShaderString = SHADER_STRING
(
uniform sampler2D inputImageTexture;
uniform mat3 convolutionMatrix;
varying vec2 textureCoordinate;
varying vec2 leftTextureCoordinate;
varying vec2 rightTextureCoordinate;
varying vec2 topTextureCoordinate;
varying vec2 topLeftTextureCoordinate;
varying vec2 topRightTextureCoordinate;
varying vec2 bottomTextureCoordinate;
varying vec2 bottomLeftTextureCoordinate;
varying vec2 bottomRightTextureCoordinate;
void main()
{
vec3 bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate).rgb;
vec3 bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate).rgb;
vec3 bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate).rgb;
vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);
vec3 leftColor = texture2D(inputImageTexture, leftTextureCoordinate).rgb;
vec3 rightColor = texture2D(inputImageTexture, rightTextureCoordinate).rgb;
vec3 topColor = texture2D(inputImageTexture, topTextureCoordinate).rgb;
vec3 topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate).rgb;
vec3 topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate).rgb;
vec3 resultColor = topLeftColor * convolutionMatrix[0][0] + topColor * convolutionMatrix[0][1] + topRightColor * convolutionMatrix[0][2];
resultColor += leftColor * convolutionMatrix[1][0] + centerColor.rgb * convolutionMatrix[1][1] + rightColor * convolutionMatrix[1][2];
resultColor += bottomLeftColor * convolutionMatrix[2][0] + bottomColor * convolutionMatrix[2][1] + bottomRightColor * convolutionMatrix[2][2];
gl_FragColor = vec4(resultColor, centerColor.a);
}
);
#endif
@implementation GPUImage3x3ConvolutionFilter
@synthesize convolutionKernel = _convolutionKernel;
#pragma mark -
#pragma mark Initialization and teardown
- (id)init;
{
if (!(self = [self initWithFragmentShaderFromString:kGPUImage3x3ConvolutionFragmentShaderString]))
{
return nil;
}
self.convolutionKernel = (GPUMatrix3x3){
{0.f, 0.f, 0.f},
{0.f, 1.f, 0.f},
{0.f, 0.f, 0.f}
};
return self;
}
- (id)initWithFragmentShaderFromString:(NSString *)fragmentShaderString;
{
if (!(self = [super initWithFragmentShaderFromString:fragmentShaderString]))
{
return nil;
}
convolutionMatrixUniform = [filterProgram uniformIndex:@"convolutionMatrix"];
return self;
}
#pragma mark -
#pragma mark Accessors
- (void)setConvolutionKernel:(GPUMatrix3x3)newValue;
{
_convolutionKernel = newValue;
[self setMatrix3f:_convolutionKernel forUniform:convolutionMatrixUniform program:filterProgram];
}
@end