IOS OpenGL ES GPUImage 图像 XYDerivative 边缘检测 GPUImageXYDerivative - ToB企服应用市场:ToB评测及商务社交产业平台

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//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES GPUImage GPUImageXYDerivativeFilter
//@Time:2022/07/02 06:30
//@Motto:不积跬步无以至千里，不积小流无以成江海，程序人生的精彩需要坚持不懈地积累！
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#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImageGradientFragmentShaderString = SHADER_STRING
(
precision highp float;
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;
uniform sampler2D inputImageTexture;
uniform float edgeStrength;
void main()
{
float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;
float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;
float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;
float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;
float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;
float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;
float verticalDerivative = -topLeftIntensity - topIntensity - topRightIntensity + bottomLeftIntensity + bottomIntensity + bottomRightIntensity;
float horizontalDerivative = -bottomLeftIntensity - leftIntensity - topLeftIntensity + bottomRightIntensity + rightIntensity + topRightIntensity;
verticalDerivative = verticalDerivative * edgeStrength;
horizontalDerivative = horizontalDerivative * edgeStrength;
// Scaling the X * Y operation so that negative numbers are not clipped in the 0..1 range. This will be expanded in the corner detection filter
gl_FragColor = vec4(horizontalDerivative * horizontalDerivative, verticalDerivative * verticalDerivative, ((verticalDerivative * horizontalDerivative) + 1.0) / 2.0, 1.0);
}
);
#else
NSString *const kGPUImageGradientFragmentShaderString = SHADER_STRING
(
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;
uniform sampler2D inputImageTexture;
uniform float edgeStrength;
void main()
{
float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;
float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;
float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;
float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;
float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;
float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;
float verticalDerivative = -topLeftIntensity - topIntensity - topRightIntensity + bottomLeftIntensity + bottomIntensity + bottomRightIntensity;
float horizontalDerivative = -bottomLeftIntensity - leftIntensity - topLeftIntensity + bottomRightIntensity + rightIntensity + topRightIntensity;
verticalDerivative = verticalDerivative * edgeStrength;
horizontalDerivative = horizontalDerivative * edgeStrength;
// Scaling the X * Y operation so that negative numbers are not clipped in the 0..1 range. This will be expanded in the corner detection filter
gl_FragColor = vec4(horizontalDerivative * horizontalDerivative, verticalDerivative * verticalDerivative, ((verticalDerivative * horizontalDerivative) + 1.0) / 2.0, 1.0);
}
);
#endif

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