`

    uniform sampler2D uSampler;
    
    varying highp vec2 vTextureCoord;
    varying highp vec3 vLighting;


// Why it is necessary to set precission for the fragment shader? 
//Vertex shader works without this, but fragment shader 
//doesn't work without this code row (as I see). 
//Why the different behaviour exist?  

  void main() {

      highp vec4 texelColor = texture2D(uSampler, vTextureCoord);
      gl_FragColor = vec4(texelColor.rgb * vLighting, texelColor.a);
      
//          gl_FragColor = mix ( vColor , texture2D(uSampler, vTextureCoord), 0.6  );
//          gl_FragColor =  texture2D(uSampler, vTextureCoord);

     //         gl_FragColor ==  vec4(1.0 , 1.0 , 1.0 , 1.0 ) ; 
}`