IOS – OpenGL ES 圖像柏林噪點/花邊噪點 GPUImagePerlinNoiseFilter

目錄一.簡介二.效果演示三.源碼下載四.猜你喜歡零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 基礎零基礎 OpenGL (ES) 學習路線推薦 : OpenGL (ES) 學習目錄 >> OpenGL ES 轉場零基礎 O ...

一.簡介
二.效果演示
三.源碼下載
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

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

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

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

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 , 圖像處理相關.
3、Blending modes : 29 filters , 混合模式相關.
4、Visual effects : 25 filters , 視覺效果相關.

GPUImagePerlinNoiseFilter 屬於 GPUImage 圖像視覺效果相關，用來處理圖像柏林噪點/花邊噪點。shader 源碼如下：

/******************************************************************************************/
//@Author:猿說編程
//@Blog(個人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES 圖像柏林噪點/花邊噪點 GPUImagePerlinNoiseFilter
//@Time:2022/06/08 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 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