IOS OpenGL ES GPUImage 影像顯示亮度最高的像素,其他為黑 GPUImageThresholdedNonMaximumSuppressionFilter

目錄

• 一.簡介
• 二.效果演示
• 三.原始碼下載
• 四.猜你喜歡

零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 基礎

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零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES GPUImage 使用

零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES GLSL 編程

一.簡介

GPUImage 共 125 個濾鏡, 分為四類

1、Color adjustments : 31 filters , 顏色處理相關
2、Image processing : 40 filters , 影像處理相關.
3、Blending modes : 29 filters , 混合模式相關.
4、Visual effects : 25 filters , 視覺效果相關.

GPUImageThresholdedNonMaximumSuppressionFilter屬于 GPUImage 影像視覺效果相關，用來處理**影像影像顯示亮度最高的像素,其他為黑效果**，相比于 GPUImageNonMaximumSuppressionFilter ，GPUImageThresholdedNonMaximumSuppressionFilter像素丟失更多，shader 原始碼如下：

/******************************************************************************************/
//@Author:猿說編程
//@Blog(個人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES GPUImage 影像顯示亮度最高的像素,其他為黑 GPUImageThresholdedNonMaximumSuppressionFilter
//@Time:2022/06/21 06:30
//@Motto:不積跬步無以至千里，不積小流無以成江海，程式人生的精彩需要堅持不懈地積累！
/******************************************************************************************/

#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImageThresholdedNonMaximumSuppressionFragmentShaderString = SHADER_STRING
(
 uniform sampler2D inputImageTexture;

 varying highp vec2 textureCoordinate;
 varying highp vec2 leftTextureCoordinate;
 varying highp vec2 rightTextureCoordinate;

 varying highp vec2 topTextureCoordinate;
 varying highp vec2 topLeftTextureCoordinate;
 varying highp vec2 topRightTextureCoordinate;

 varying highp vec2 bottomTextureCoordinate;
 varying highp vec2 bottomLeftTextureCoordinate;
 varying highp vec2 bottomRightTextureCoordinate;

 uniform lowp float threshold;

 void main()
 {
     lowp float bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate).r;
     lowp float bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
     lowp float bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
     lowp vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);
     lowp float leftColor = texture2D(inputImageTexture, leftTextureCoordinate).r;
     lowp float rightColor = texture2D(inputImageTexture, rightTextureCoordinate).r;
     lowp float topColor = texture2D(inputImageTexture, topTextureCoordinate).r;
     lowp float topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate).r;
     lowp float topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate).r;

     // Use a tiebreaker for pixels to the left and immediately above this one
     lowp float multiplier = 1.0 - step(centerColor.r, topColor);
     multiplier = multiplier * (1.0 - step(centerColor.r, topLeftColor));
     multiplier = multiplier * (1.0 - step(centerColor.r, leftColor));
     multiplier = multiplier * (1.0 - step(centerColor.r, bottomLeftColor));

     lowp float maxValue = https://www.cnblogs.com/shuopython/archive/2022/07/11/max(centerColor.r, bottomColor);
     maxValue = max(maxValue, bottomRightColor);
     maxValue = max(maxValue, rightColor);
     maxValue = max(maxValue, topRightColor);

     lowp float finalValue = centerColor.r * step(maxValue, centerColor.r) * multiplier;
     finalValue = step(threshold, finalValue);

     gl_FragColor = vec4(finalValue, finalValue, finalValue, 1.0);
//
//     gl_FragColor = vec4((centerColor.rgb * step(maxValue, step(threshold, centerColor.r)) * multiplier), 1.0);
 }
);

NSString *const kGPUImageThresholdedNonMaximumSuppressionPackedColorspaceFragmentShaderString = SHADER_STRING
(
 uniform sampler2D inputImageTexture;

 varying highp vec2 textureCoordinate;
 varying highp vec2 leftTextureCoordinate;
 varying highp vec2 rightTextureCoordinate;

 varying highp vec2 topTextureCoordinate;
 varying highp vec2 topLeftTextureCoordinate;
 varying highp vec2 topRightTextureCoordinate;

 varying highp vec2 bottomTextureCoordinate;
 varying highp vec2 bottomLeftTextureCoordinate;
 varying highp vec2 bottomRightTextureCoordinate;

 uniform lowp float threshold;
 uniform highp float texelWidth;
 uniform highp float texelHeight;

 highp float encodedIntensity(highp vec3 sourceColor)
 {
     return (sourceColor.b * 256.0 * 256.0 + sourceColor.g * 256.0 + sourceColor.r);
 }

 void main()
 {
     highp float bottomColor = encodedIntensity(texture2D(inputImageTexture, bottomTextureCoordinate).rgb);
     highp float bottomLeftColor = encodedIntensity(texture2D(inputImageTexture, bottomLeftTextureCoordinate).rgb);
     highp float bottomRightColor = encodedIntensity(texture2D(inputImageTexture, bottomRightTextureCoordinate).rgb);
     highp float centerColor = encodedIntensity(texture2D(inputImageTexture, textureCoordinate).rgb);
     highp float leftColor = encodedIntensity(texture2D(inputImageTexture, leftTextureCoordinate).rgb);
     highp float rightColor = encodedIntensity(texture2D(inputImageTexture, rightTextureCoordinate).rgb);
     highp float topColor = encodedIntensity(texture2D(inputImageTexture, topTextureCoordinate).rgb);
     highp float topRightColor = encodedIntensity(texture2D(inputImageTexture, topRightTextureCoordinate).rgb);
     highp float topLeftColor = encodedIntensity(texture2D(inputImageTexture, topLeftTextureCoordinate).rgb);

     highp float secondStageColor1 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, -2.0 * texelHeight)).rgb);
     highp float secondStageColor2 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, -1.0 * texelHeight)).rgb);
     highp float secondStageColor3 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, 0.0)).rgb);
     highp float secondStageColor4 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, 1.0 * texelHeight)).rgb);
     highp float secondStageColor5 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-2.0 * texelWidth, 2.0 * texelHeight)).rgb);
     highp float secondStageColor6 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-1.0 * texelWidth, 2.0 * texelHeight)).rgb);
     highp float secondStageColor7 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(0.0, 2.0 * texelHeight)).rgb);
     highp float secondStageColor8 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(1.0 * texelWidth, 2.0 * texelHeight)).rgb);

     highp float thirdStageColor1 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(-1.0 * texelWidth, -2.0 * texelHeight)).rgb);
     highp float thirdStageColor2 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(0.0, -2.0 * texelHeight)).rgb);
     highp float thirdStageColor3 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(1.0 * texelWidth, -2.0 * texelHeight)).rgb);
     highp float thirdStageColor4 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, -2.0 * texelHeight)).rgb);
     highp float thirdStageColor5 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, -1.0 * texelHeight)).rgb);
     highp float thirdStageColor6 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, 0.0)).rgb);
     highp float thirdStageColor7 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, 1.0 * texelHeight)).rgb);
     highp float thirdStageColor8 = encodedIntensity(texture2D(inputImageTexture, textureCoordinate + vec2(2.0 * texelWidth, 2.0 * texelHeight)).rgb);

     // Use a tiebreaker for pixels to the left and immediately above this one
     highp float multiplier = 1.0 - step(centerColor, topColor);
     multiplier = multiplier * (1.0 - step(centerColor, topLeftColor));
     multiplier = multiplier * (1.0 - step(centerColor, leftColor));
     multiplier = multiplier * (1.0 - step(centerColor, bottomLeftColor));

     multiplier = multiplier * (1.0 - step(centerColor, secondStageColor1));
     multiplier = multiplier * (1.0 - step(centerColor, secondStageColor2));
     multiplier = multiplier * (1.0 - step(centerColor, secondStageColor3));
     multiplier = multiplier * (1.0 - step(centerColor, secondStageColor4));
     multiplier = multiplier * (1.0 - step(centerColor, secondStageColor5));
     multiplier = multiplier * (1.0 - step(centerColor, secondStageColor6));
     multiplier = multiplier * (1.0 - step(centerColor, secondStageColor7));
     multiplier = multiplier * (1.0 - step(centerColor, secondStageColor8));

     highp float maxValue = max(centerColor, bottomColor);
     maxValue = max(maxValue, bottomRightColor);
     maxValue = max(maxValue, rightColor);
     maxValue = max(maxValue, topRightColor);

     maxValue = max(maxValue, thirdStageColor1);
     maxValue = max(maxValue, thirdStageColor2);
     maxValue = max(maxValue, thirdStageColor3);
     maxValue = max(maxValue, thirdStageColor4);
     maxValue = max(maxValue, thirdStageColor5);
     maxValue = max(maxValue, thirdStageColor6);
     maxValue = max(maxValue, thirdStageColor7);
     maxValue = max(maxValue, thirdStageColor8);

     highp float midValue = centerColor * step(maxValue, centerColor) * multiplier;
     highp float finalValue = step(threshold, midValue);

     gl_FragColor = vec4(finalValue * centerColor, topLeftColor, topRightColor, topColor);
 }
);
#else
NSString *const kGPUImageThresholdedNonMaximumSuppressionFragmentShaderString = SHADER_STRING
(
 uniform sampler2D inputImageTexture;

 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 float threshold;

 void main()
 {
     float bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate).r;
     float bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
     float bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
     vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);
     float leftColor = texture2D(inputImageTexture, leftTextureCoordinate).r;
     float rightColor = texture2D(inputImageTexture, rightTextureCoordinate).r;
     float topColor = texture2D(inputImageTexture, topTextureCoordinate).r;
     float topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate).r;
     float topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate).r;

     // Use a tiebreaker for pixels to the left and immediately above this one
     float multiplier = 1.0 - step(centerColor.r, topColor);
     multiplier = multiplier * (1.0 - step(centerColor.r, topLeftColor));
     multiplier = multiplier * (1.0 - step(centerColor.r, leftColor));
     multiplier = multiplier * (1.0 - step(centerColor.r, bottomLeftColor));

     float maxValue = max(centerColor.r, bottomColor);
     maxValue = max(maxValue, bottomRightColor);
     maxValue = max(maxValue, rightColor);
     maxValue = max(maxValue, topRightColor);

     float finalValue = centerColor.r * step(maxValue, centerColor.r) * multiplier;
     finalValue = step(threshold, finalValue);

     gl_FragColor = vec4(finalValue, finalValue, finalValue, 1.0);
     //
     //     gl_FragColor = vec4((centerColor.rgb * step(maxValue, step(threshold, centerColor.r)) * multiplier), 1.0);
 }
);

NSString *const kGPUImageThresholdedNonMaximumSuppressionPackedColorspaceFragmentShaderString = SHADER_STRING
(
 uniform sampler2D inputImageTexture;

 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 float threshold;

 void main()
 {
     float bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate).r;
     float bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;
     float bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;
     vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);
     float leftColor = texture2D(inputImageTexture, leftTextureCoordinate).r;
     float rightColor = texture2D(inputImageTexture, rightTextureCoordinate).r;
     float topColor = texture2D(inputImageTexture, topTextureCoordinate).r;
     float topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate).r;
     float topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate).r;

     // Use a tiebreaker for pixels to the left and immediately above this one
     float multiplier = 1.0 - step(centerColor.r, topColor);
     multiplier = multiplier * (1.0 - step(centerColor.r, topLeftColor));
     multiplier = multiplier * (1.0 - step(centerColor.r, leftColor));
     multiplier = multiplier * (1.0 - step(centerColor.r, bottomLeftColor));

     float maxValue = max(centerColor.r, bottomColor);
     maxValue = max(maxValue, bottomRightColor);
     maxValue = max(maxValue, rightColor);
     maxValue = max(maxValue, topRightColor);

     float finalValue = centerColor.r * step(maxValue, centerColor.r) * multiplier;
     finalValue = step(threshold, finalValue);

     gl_FragColor = vec4(finalValue, finalValue, finalValue, 1.0);
     //
     //     gl_FragColor = vec4((centerColor.rgb * step(maxValue, step(threshold, centerColor.r)) * multiplier), 1.0);
 }
 );
#endif

二.效果演示

使用 GPUImageThresholdedNonMaximumSuppressionFilter 完成影像顯示亮度最高的像素,其他為黑,原圖如下：

使用 GPUImageThresholdedNonMaximumSuppressionFilter 完成影像顯示亮度最高的像素,其他為黑****,效果如下：

三.原始碼下載

OpenGL ES Demo 下載地址 : IOS – OpenGL ES GPUImage 影像顯示亮度最高的像素,其他為黑 GPUImageThresholdedNonMaximumSuppressionFilter

四.猜你喜歡

1. IOS – OPenGL ES 設定影像亮度 GPUImageBrightnessFilter
2. IOS – OPenGL ES 調節影像曝光度 GPUImageExposureFilter
3. IOS – OpenGL ES 調節影像對比度 GPUImageContrastFilter
4. IOS – OPenGL ES 調節影像飽和度 GPUImageSaturationFilter
5. IOS – OPenGL ES 調節影像伽馬線 GPUImageGammaFilter
6. IOS – OpenGL ES 調節影像反色 GPUImageColorInvertFilter
7. IOS – OpenGL ES 調節影像褐色 GPUImageSepiaFilter
8. IOS – OpenGL ES 調節影像灰色 GPUImageGrayscaleFilter
9. IOS – OpenGL ES 調節影像 RGB 通道 GPUImageRGBFilter
10. IOS – OpenGL ES 調節影像不透明度 GPUImageOpacityFilter
11. IOS – OpenGL ES 調節影像陰影 GPUImageHighlightShadowFilter
12. IOS – OpenGL ES 調節影像色彩替換 GPUImageFalseColorFilter
13. GPUImage – 色彩直方圖 GPUImageHistogramFilter
14. GPUImage – 色彩直方圖 GPUImageHistogramGenerator
15. GPUImage – 像素平均色值 GPUImageAverageColor
16. GPUImage – 亮度平均 GPUImageLuminosity
17. IOS – OpenGL ES 調節影像色度 GPUImageHueFilter
18. IOS – OpenGL ES 指定顏色摳圖 GPUImageChromaKeyFilter
19. IOS – OpenGL ES 調節影像白平衡/色溫 GPUImageWhiteBalanceFilter
20. IOS – OpenGL ES 設定影像 lookup 濾鏡 GPUImageLookupFilter
21. IOS – OpenGL ES 設定影像濾鏡 GPUImageAmatorkaFilter
22. IOS – OpenGL ES 設定影像濾鏡 GPUImageSoftEleganceFilter
23. IOS – OpenGL ES 設定影像銳化 GPUImageSharpenFilter
24. IOS – OpenGL ES 繪制十字 GPUImageCrosshairGenerator
25. IOS – OpenGL ES 繪制線條 GPUImageLineGenerator
26. IOS – OpenGL ES 設定影像黑白燥點 GPUImageLocalBinaryPatternFilter
27. IOS – OpenGL ES 設定影像卡通效果（黑色粗線描邊） GPUImageToonFilter
28. IOS – OpenGL ES 桑原濾波/水粉畫模糊效果 GPUImageKuwaharaFilter
29. IOS – OpenGL ES 黑白馬賽克效果 GPUImageMosaicFilter
30. IOS – OpenGL ES 像素化馬賽克效果 GPUImagePixellateFilter
31. IOS – OpenGL ES 同心圓像素化馬賽克效果 GPUImagePolarPixel
32. IOS – OpenGL ES 黑白網狀效果 GPUImageCrosshatchFilter
33. IOS – OpenGL ES 色彩丟失/模糊效果 GPUImageColorPackingFilter
34. IOS – OpenGL ES 影像暈影 GPUImageVignetteFilter
35. IOS – OpenGL ES 影像漩渦 GPUImageSwirlFilter
36. IOS – OpenGL ES 影像魚眼擴散效果 GPUImageBulgeDistortionFilter
37. IOS – OpenGL ES 影像魚眼移動效果 GPUImageBulgeDistortionFilter
38. IOS – OpenGL ES 影像凹面鏡移動效果 GPUImagePinchDistortionFilter
39. IOS – OpenGL ES 影像凹面鏡放大效果 GPUImagePinchDistortionFilter
40. IOS – OpenGL ES 影像哈哈鏡效果 GPUImageStretchDistortionFilter
41. IOS – OpenGL ES 影像水晶球效果 GPUImageGlassSphereFilter
42. IOS – OpenGL ES 影像球形折射 GPUImageSphereRefractionFilter
43. IOS – OpenGL ES 影像色調分離噪點效果 GPUImagePosterizeFilter
44. IOS – OpenGL ES 影像 CGA 色彩濾鏡 GPUImageCGAColorspaceFilter
45. IOS – OpenGL ES 影像柏林噪點/花邊噪點 GPUImagePerlinNoiseFilter
46. IOS – OpenGL ES 影像加亮邊緣 GPUImage3x3ConvolutionFilter
47. IOS – OpenGL ES 影像浮雕 3d 效果 GPUImageEmbossFilter
48. IOS – OpenGL ES 影像馬賽克圓點 GPUImagePolkaDotFilter
49. IOS – OpenGL ES 影像侵蝕邊緣黑白模糊 GPUImageErosionFilter
50. IOS – OpenGL ES 影像侵蝕邊緣色彩模糊 GPUImageRGBErosionFilter
51. IOS – OpenGL ES 影像擴展邊緣黑白模糊 GPUImageDilationFilter
52. IOS – OpenGL ES 影像擴展邊緣彩色模糊 GPUImageRGBDilationFilter
53. IOS – OpenGL ES GPUImage 黑白色調模糊 GPUImageOpeningFilter
54. IOS – OpenGL ES GPUImage 彩色模糊 GPUImageRGBOpeningFilter
55. IOS – OpenGL ES GPUImage 影像黑白色調模糊/暗色提亮 GPUImageClosingFilter
56. IOS – OpenGL ES GPUImage 影像彩色調模糊/暗色提亮 GPUImageRGBClosingFilter
57. IOS – OpenGL ES GPUImage 影像 Lanczos 重取樣模糊效果 GPUImageLanczosResamplingFilter
58. IOS – OpenGL ES GPUImage 影像顯示亮度最高的像素,其他為黑 GPUImageNonMaximumSuppressionFilter
59. IOS – OpenGL ES GPUImage 影像顯示亮度最高的像素,其他為黑 GPUImageThresholdedNonMaximumSuppressionFilter

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