Simple eye distortion

eye_distortion.fsh

precision highp float;
varying highp vec2 textureCoordinate;
uniform sampler2D inputImageTexture;
uniform lowp vec2 leftPupil;
uniform lowp vec2 rightPupil;
uniform lowp float intensity;
 
void main() {
    vec2 p = vec2(textureCoordinate.x, textureCoordinate.y);
    if (intensity != 0.0) {
        vec2 leftEye = vec2(leftPupil.x, leftPupil.y);
        vec2 rightEye = vec2(rightPupil.x, rightPupil.y);
        float weight = 0.0;
        float dis = distance(leftEye, rightEye);
        float radius = dis * 0.27;
        if (distance(p, leftEye) <= radius) {
            weight = pow(distance(p, leftEye) / radius, intensity);
            p = leftEye + (p - leftEye) * weight;
        } else if (distance(p, rightEye) <= radius) {
            weight = pow(distance(p, rightEye) / radius, intensity);
            p = rightEye + (p - rightEye) * weight;
        }
    }
    gl_FragColor = texture2D(inputImageTexture, p);
}