text: export default `
  
  uniform float uTime;        // normalized progress time 
  uniform sampler2D uTexture; // texture for particles
  varying vec2 vUv;           // UV coordinate
  varying float vBright;      // brightness
  
  void main() {
      vec3 color = vec3(vUv, 1.0) * vBright;
  
      gl_FragColor  = texture2D(uTexture, gl_PointCoord);
      gl_FragColor *= vec4(color, 0.8);
  }
  `;
  