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.
GPUImageSphereRefractionFilter 属于 GPUImage 图像视觉效果相关，用来处理图像球形折射效果。shader 源码如下：
代码语言：javascript复制/******************************************************************************************/
//@Author:猿说编程
//@Blog(个人博客地址): www.codersrc.com
//@File:IOS – OpenGL ES 图像球形折射 GPUImageSphereRefractionFilter
//@Time:2022/06/03 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 kGPUImageSphereRefractionFragmentShaderString = SHADER_STRING
(
varying highp vec2 textureCoordinate;
uniform sampler2D inputImageTexture;
uniform highp vec2 center;
uniform highp float radius;
uniform highp float aspectRatio;
uniform highp float refractiveIndex;
void main()
{
highp vec2 textureCoordinateToUse = vec2(textureCoordinate.x, (textureCoordinate.y * aspectRatio 0.5 - 0.5 * aspectRatio));
highp float distanceFromCenter = distance(center, textureCoordinateToUse);
lowp float checkForPresenceWithinSphere = step(distanceFromCenter, radius);
distanceFromCenter = distanceFromCenter / radius;
highp float normalizedDepth = radius * sqrt(1.0 - distanceFromCenter * distanceFromCenter);
highp vec3 sphereNormal = normalize(vec3(textureCoordinateToUse - center, normalizedDepth));
highp vec3 refractedVector = refract(vec3(0.0, 0.0, -1.0), sphereNormal, refractiveIndex);
gl_FragColor = texture2D(inputImageTexture, (refractedVector.xy 1.0) * 0.5) * checkForPresenceWithinSphere;
}
);
#else
NSString *const kGPUImageSphereRefractionFragmentShaderString = SHADER_STRING
(
varying vec2 textureCoordinate;
uniform sampler2D inputImageTexture;
uniform vec2 center;
uniform float radius;
uniform float aspectRatio;
uniform float refractiveIndex;
void main()
{
vec2 textureCoordinateToUse = vec2(textureCoordinate.x, (textureCoordinate.y * aspectRatio 0.5 - 0.5 * aspectRatio));
float distanceFromCenter = distance(center, textureCoordinateToUse);
float checkForPresenceWithinSphere = step(distanceFromCenter, radius);
distanceFromCenter = distanceFromCenter / radius;
float normalizedDepth = radius * sqrt(1.0 - distanceFromCenter * distanceFromCenter);
vec3 sphereNormal = normalize(vec3(textureCoordinateToUse - center, normalizedDepth));
vec3 refractedVector = refract(vec3(0.0, 0.0, -1.0), sphereNormal, refractiveIndex);
gl_FragColor = texture2D(inputImageTexture, (refractedVector.xy 1.0) * 0.5) * checkForPresenceWithinSphere;
}
);
#endif二.效果演示
使用GPUImageSphereRefractionFilter** **完成**图像球形折射**效果****，原图：
使用GPUImageSphereRefractionFilter** **完成图像球形折射效果****
三.源码下载
OpenGL ES Demo 下载地址 : IOS – OpenGL ES 图像球形折射 GPUImageSphereRefractionFilter
