首页 > 编程语言> > IOS – OpenGL ES 图像柏林噪点/花边噪点 GPUImagePerlinNoiseFilter

IOS – OpenGL ES 图像柏林噪点/花边噪点 GPUImagePerlinNoiseFilter

2022-06-13 21:33:53 作者：互联网

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.

GPUImagePerlinNoiseFilter 属于 GPUImage 图像视觉效果相关，用来处理图像柏林噪点/花边噪点。shader 源码如下：

/******************************************************************************************/
//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES 图像柏林噪点/花边噪点 GPUImagePerlinNoiseFilter
//@Time:2022/06/08 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 kGPUImagePerlinNoiseFragmentShaderString = SHADER_STRING
(
 precision highp float;
 varying highp vec2 textureCoordinate;
 uniform float scale;

 uniform vec4 colorStart;
 uniform vec4 colorFinish;

 //
 // Description : Array and textureless GLSL 2D/3D/4D simplex
 // noise functions.
 // Author : Ian McEwan, Ashima Arts.
 // Maintainer : ijm
 // Lastmod : 20110822 (ijm)
 // License : Copyright (C) 2011 Ashima Arts. All rights reserved.
 // Distributed under the MIT License. See LICENSE file.
 // https://github.com/ashima/webgl-noise
 //

 vec4 mod289(vec4 x)
{
    return x - floor(x * (1.0 / 289.0)) * 289.0;
}

 vec4 permute(vec4 x)
{
    return mod289(((x*34.0)+1.0)*x);
}

 vec4 taylorInvSqrt(vec4 r)
{
    return 1.79284291400159 - 0.85373472095314 * r;
}

 vec2 fade(vec2 t) {
     return t*t*t*(t*(t*6.0-15.0)+10.0);
 }

 // Classic Perlin noise
 float cnoise(vec2 P)
{
    vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);
    vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);
    Pi = mod289(Pi); // To avoid truncation effects in permutation
    vec4 ix = Pi.xzxz;
    vec4 iy = Pi.yyww;
    vec4 fx = Pf.xzxz;
    vec4 fy = Pf.yyww;

    vec4 i = permute(permute(ix) + iy);

    vec4 gx = fract(i * (1.0 / 41.0)) * 2.0 - 1.0 ;
    vec4 gy = abs(gx) - 0.5 ;
    vec4 tx = floor(gx + 0.5);
    gx = gx - tx;

    vec2 g00 = vec2(gx.x,gy.x);
    vec2 g10 = vec2(gx.y,gy.y);
    vec2 g01 = vec2(gx.z,gy.z);
    vec2 g11 = vec2(gx.w,gy.w);

    vec4 norm = taylorInvSqrt(vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
    g00 *= norm.x;
    g01 *= norm.y;
    g10 *= norm.z;
    g11 *= norm.w;

    float n00 = dot(g00, vec2(fx.x, fy.x));
    float n10 = dot(g10, vec2(fx.y, fy.y));
    float n01 = dot(g01, vec2(fx.z, fy.z));
    float n11 = dot(g11, vec2(fx.w, fy.w));

    vec2 fade_xy = fade(Pf.xy);
    vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);
    float n_xy = mix(n_x.x, n_x.y, fade_xy.y);
    return 2.3 * n_xy;
}


 void main()
 {

     float n1 = (cnoise(textureCoordinate * scale) + 1.0) / 2.0;

     vec4 colorDiff = colorFinish - colorStart;
     vec4 color = colorStart + colorDiff * n1;

     gl_FragColor = color;
 }
);
#else
NSString *const kGPUImagePerlinNoiseFragmentShaderString = SHADER_STRING
(
 varying vec2 textureCoordinate;
 uniform float scale;

 uniform vec4 colorStart;
 uniform vec4 colorFinish;

 //
 // Description : Array and textureless GLSL 2D/3D/4D simplex
 // noise functions.
 // Author : Ian McEwan, Ashima Arts.
 // Maintainer : ijm
 // Lastmod : 20110822 (ijm)
 // License : Copyright (C) 2011 Ashima Arts. All rights reserved.
 // Distributed under the MIT License. See LICENSE file.
 // https://github.com/ashima/webgl-noise
 //

 vec4 mod289(vec4 x)
{
    return x - floor(x * (1.0 / 289.0)) * 289.0;
}

 vec4 permute(vec4 x)
{
    return mod289(((x*34.0)+1.0)*x);
}

 vec4 taylorInvSqrt(vec4 r)
{
    return 1.79284291400159 - 0.85373472095314 * r;
}

 vec2 fade(vec2 t) {
     return t*t*t*(t*(t*6.0-15.0)+10.0);
 }

 // Classic Perlin noise
 float cnoise(vec2 P)
{
    vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);
    vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);
    Pi = mod289(Pi); // To avoid truncation effects in permutation
    vec4 ix = Pi.xzxz;
    vec4 iy = Pi.yyww;
    vec4 fx = Pf.xzxz;
    vec4 fy = Pf.yyww;

    vec4 i = permute(permute(ix) + iy);

    vec4 gx = fract(i * (1.0 / 41.0)) * 2.0 - 1.0 ;
    vec4 gy = abs(gx) - 0.5 ;
    vec4 tx = floor(gx + 0.5);
    gx = gx - tx;

    vec2 g00 = vec2(gx.x,gy.x);
    vec2 g10 = vec2(gx.y,gy.y);
    vec2 g01 = vec2(gx.z,gy.z);
    vec2 g11 = vec2(gx.w,gy.w);

    vec4 norm = taylorInvSqrt(vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
    g00 *= norm.x;
    g01 *= norm.y;
    g10 *= norm.z;
    g11 *= norm.w;

    float n00 = dot(g00, vec2(fx.x, fy.x));
    float n10 = dot(g10, vec2(fx.y, fy.y));
    float n01 = dot(g01, vec2(fx.z, fy.z));
    float n11 = dot(g11, vec2(fx.w, fy.w));

    vec2 fade_xy = fade(Pf.xy);
    vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);
    float n_xy = mix(n_x.x, n_x.y, fade_xy.y);
    return 2.3 * n_xy;
 }

 void main()
 {

     float n1 = (cnoise(textureCoordinate * scale) + 1.0) / 2.0;

     vec4 colorDiff = colorFinish - colorStart;
     vec4 color = colorStart + colorDiff * n1;

     gl_FragColor = color;
 }
);
#endif

二.效果演示

使用GPUImagePerlinNoiseFilter 完成**图像柏林噪点/花边噪点******

三.源码下载

OpenGL ES Demo 下载地址 : IOS – OpenGL ES 图像柏林噪点/花边噪点 GPUImagePerlinNoiseFilter

四.猜你喜欢

本文由博客 - 猿说编程猿说编程发布！

标签：噪点,OpenGL,IOS,vec4,vec2,图像,ES
来源： https://www.cnblogs.com/shuopython/p/16372347.html