IOS OpenGL ES GPUImage 图像显示亮度最高的像素,其他为黑 GPUImageNonMaximumSuppressionFilte

一.简介
二.效果演示
三.源码下载
四.猜你喜欢

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

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

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

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

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

零基础 OpenGL (ES) 学习路线推荐 : OpenGL (ES) 学习目录 >> OpenGL ES GLSL 编程

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.

GPUImageNonMaximumSuppressionFilter 属于 GPUImage 图像视觉效果相关，用来处理**图像图像显示亮度最高的像素,其他为黑效果**。shader 源码如下：

/******************************************************************************************/
//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES GPUImage 图像显示亮度最高的像素,其他为黑 GPUImageNonMaximumSuppressionFilter
//@Time:2022/06/21 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！
/******************************************************************************************/


#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
NSString *const kGPUImageNonMaximumSuppressionFragmentShaderString = 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;

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

     gl_FragColor = vec4((centerColor.rgb * step(maxValue, centerColor.r) * multiplier), 1.0);
 }
);
#else
NSString *const kGPUImageNonMaximumSuppressionFragmentShaderString = 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;

 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);

     gl_FragColor = vec4((centerColor.rgb * step(maxValue, centerColor.r) * multiplier), 1.0);
 }
);
#endif
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96

二.效果演示

使用 GPUImageNonMaximumSuppressionFilter 完成图像显示亮度最高的像素,其他为黑****,原图如下：

使用 GPUImageNonMaximumSuppressionFilter 完成图像显示亮度最高的像素,其他为黑****,效果如下：

三.源码下载

OpenGL ES Demo 下载地址 : IOS – OpenGL ES GPUImage 图像显示亮度最高的像素,其他为黑 GPUImageNonMaximumSuppressionFilter

四.猜你喜欢

相关阅读:
之前续写抖音开发者接入字节小游戏的缓存一下,现在说一下在 Windows 或者 Mac 如何用终端更换路径?
Redis的基础与django使用redis
人工智能之机器学习
算法-递推
Python 实现单例模式的五种写法！
QT搭建的Ros/librviz的GUI软件
这两个面试题一口气全做对的没几个吧
剑指 Offer 30. 包含min函数的栈C++(详解)
Spring Boot 2.x系列【8】功能篇之自定义启动Banner
Docker 学习笔记一

原文地址：https://blog.csdn.net/ZhaDeNianQu/article/details/125549696