1.代码

#define PI 3.1415926

vec2 Twist(vec2 uv){
    vec2 center = vec2(0.0,0.0);
    float dist = distance(uv, center);
    float theta = atan(uv.y, uv.x);
    float strength = 1.0 - smoothstep(0.0, 1.0, dist);
    vec2 offset = vec2(sin(theta), cos(theta)) * strength;
    return uv + offset;
}

void mainImage( out vec4 fragColor, in vec2 fragCoord ) {
 // 定义贴图坐标
    vec2 uv = fragCoord / iResolution.xy;
    uv -= 0.5;

    uv = Twist(uv);
    vec3 c = texture(iChannel0, uv).rgb;
    fragColor = vec4(vec3(c), 1.0);
}

正常的图片

扭曲后的: