IOS – OpenGL ES 设置图像锐化 GPUImageSharpenFilter

目录

• 一.简介
• 二.效果演示
• 三.源码下载
• 四.猜你喜欢

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零基础 OpenGL (ES) 学习路线推荐 : OpenGL (ES) 学习目录 >> OpenGL ES GPUImage 使用

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一.简介

GPUImage 共 125 个滤镜, 分为四类

1、Color adjustments : 31 filters , 颜色处理相关
2、Image processing : 40 filters , 图像处理相关.
3、Blending modes : 29 filters , 混合模式相关.
4、Visual effects : 25 filters , 视觉效果相关.

GPUImageSharpenFilter 属于 GPUImage 图像处理相关，用来处理图像锐化效果，shader 源码如下：

/******************************************************************************************/
//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES 设置图像锐化 GPUImageSharpenFilter
//@Time:2022/04/17 07:30
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NSString \*const kGPUImageSharpenVertexShaderString = SHADER_STRING
(
attribute vec4 position;
attribute vec4 inputTextureCoordinate;

uniform float imageWidthFactor;
uniform float imageHeightFactor;
uniform float sharpness;

varying vec2 textureCoordinate;
varying vec2 leftTextureCoordinate;
varying vec2 rightTextureCoordinate;
varying vec2 topTextureCoordinate;
varying vec2 bottomTextureCoordinate;

varying float centerMultiplier;
varying float edgeMultiplier;

void main()
{
gl_Position = position;

     vec2 widthStep = vec2(imageWidthFactor, 0.0);
     vec2 heightStep = vec2(0.0, imageHeightFactor);

     textureCoordinate = inputTextureCoordinate.xy;
     leftTextureCoordinate = inputTextureCoordinate.xy - widthStep;
     rightTextureCoordinate = inputTextureCoordinate.xy + widthStep;
     topTextureCoordinate = inputTextureCoordinate.xy + heightStep;
     bottomTextureCoordinate = inputTextureCoordinate.xy - heightStep;

     centerMultiplier = 1.0 + 4.0 * sharpness;
     edgeMultiplier = sharpness;

}
);

#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString \*const kGPUImageSharpenFragmentShaderString = SHADER_STRING
(
precision highp float;

varying highp vec2 textureCoordinate;
varying highp vec2 leftTextureCoordinate;
varying highp vec2 rightTextureCoordinate;
varying highp vec2 topTextureCoordinate;
varying highp vec2 bottomTextureCoordinate;

varying highp float centerMultiplier;
varying highp float edgeMultiplier;

uniform sampler2D inputImageTexture;

void main()
{
mediump vec3 textureColor = texture2D(inputImageTexture, textureCoordinate).rgb;
mediump vec3 leftTextureColor = texture2D(inputImageTexture, leftTextureCoordinate).rgb;
mediump vec3 rightTextureColor = texture2D(inputImageTexture, rightTextureCoordinate).rgb;
mediump vec3 topTextureColor = texture2D(inputImageTexture, topTextureCoordinate).rgb;
mediump vec3 bottomTextureColor = texture2D(inputImageTexture, bottomTextureCoordinate).rgb;

     gl_FragColor = vec4((textureColor * centerMultiplier - (leftTextureColor * edgeMultiplier + rightTextureColor * edgeMultiplier + topTextureColor * edgeMultiplier + bottomTextureColor * edgeMultiplier)), texture2D(inputImageTexture, bottomTextureCoordinate).w);

}
);
#else
NSString \*const kGPUImageSharpenFragmentShaderString = SHADER_STRING
(
varying vec2 textureCoordinate;
varying vec2 leftTextureCoordinate;
varying vec2 rightTextureCoordinate;
varying vec2 topTextureCoordinate;
varying vec2 bottomTextureCoordinate;

varying float centerMultiplier;
varying float edgeMultiplier;

uniform sampler2D inputImageTexture;

void main()
{
vec3 textureColor = texture2D(inputImageTexture, textureCoordinate).rgb;
vec3 leftTextureColor = texture2D(inputImageTexture, leftTextureCoordinate).rgb;
vec3 rightTextureColor = texture2D(inputImageTexture, rightTextureCoordinate).rgb;
vec3 topTextureColor = texture2D(inputImageTexture, topTextureCoordinate).rgb;
vec3 bottomTextureColor = texture2D(inputImageTexture, bottomTextureCoordinate).rgb;

     gl_FragColor = vec4((textureColor * centerMultiplier - (leftTextureColor * edgeMultiplier + rightTextureColor * edgeMultiplier + topTextureColor * edgeMultiplier + bottomTextureColor * edgeMultiplier)), texture2D(inputImageTexture, bottomTextureCoordinate).w);

}
);
#endif

二.效果演示

使用GPUImageSharpenFilter** 处理图片示例**，原图：

GPUImageSharpenFilter 效果图：

三.源码下载

OpenGL ES Demo 下载地址 : IOS – OpenGL ES 设置图像滤镜 GPUImageSharpenFilter

四.猜你喜欢

1. IOS – OPenGL ES 设置图像亮度 GPUImageBrightnessFilter
2. IOS – OPenGL ES 调节图像曝光度 GPUImageExposureFilter
3. IOS – OpenGL ES 调节图像对比度 GPUImageContrastFilter
4. IOS – OPenGL ES 调节图像饱和度 GPUImageSaturationFilter
5. IOS – OPenGL ES 调节图像伽马线 GPUImageGammaFilter
6. IOS – OpenGL ES 调节图像反色 GPUImageColorInvertFilter
7. IOS – OpenGL ES 调节图像褐色 GPUImageSepiaFilter
8. IOS – OpenGL ES 调节图像灰色 GPUImageGrayscaleFilter
9. IOS – OpenGL ES 调节图像 RGB 通道 GPUImageRGBFilter
10. IOS – OpenGL ES 调节图像不透明度 GPUImageOpacityFilter
11. IOS – OpenGL ES 调节图像阴影 GPUImageHighlightShadowFilter
12. IOS – OpenGL ES 调节图像色彩替换 GPUImageFalseColorFilter
13. GPUImage – 色彩直方图 GPUImageHistogramFilter
14. GPUImage – 色彩直方图 GPUImageHistogramGenerator
15. GPUImage – 像素平均色值 GPUImageAverageColor
16. GPUImage – 亮度平均 GPUImageLuminosity
17. IOS – OpenGL ES 调节图像色度 GPUImageHueFilter
18. IOS – OpenGL ES 指定颜色抠图 GPUImageChromaKeyFilter
19. IOS – OpenGL ES 调节图像白平衡/色温 GPUImageWhiteBalanceFilter
20. IOS – OpenGL ES 设置图像 lookup 滤镜 GPUImageLookupFilter
21. IOS – OpenGL ES 设置图像滤镜 GPUImageAmatorkaFilter
22. IOS – OpenGL ES 设置图像滤镜 GPUImageSoftEleganceFilter
23. IOS – OpenGL ES 设置图像滤镜 GPUImageLineGenerator
24. IOS – OpenGL ES 设置图像锐化 GPUImageSharpenFilter

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