@petkoneo/phaser3-rex-plugins/plugins/shaders/glowfilter/glowfilter-frag.js

Plugins of phaser3

// https://gist.github.com/MatthewBarker/032c325ef8577c6d0188

const frag = `\
#ifdef GL_FRAGMENT_PRECISION_HIGH
#define highmedp highp
#else
#define highmedp mediump
#endif
precision highmedp float;

// Scene buffer
uniform sampler2D uMainSampler; 
varying vec2 outTexCoord;

// Effect parameters
uniform float intensity;

void main() {
  vec4 front = texture2D(uMainSampler, outTexCoord);
  vec4 sum = vec4(0);
  for(int xx = -4; xx <= 4; xx++) {
    for(int yy = -3; yy <= 3; yy++) {
      float dist = sqrt(float(xx*xx) + float(yy*yy));
      float factor = 0.0;
      if (dist == 0.0) {
        factor = 2.0;
      } else {
        factor = 2.0/abs(float(dist));
      }
      sum += texture2D(uMainSampler, outTexCoord + vec2(xx, yy) * 0.002) * factor;
    }
  }
  
  gl_FragColor = mix(front, sum, intensity);
}
`;

export default frag;