text: export default /* glsl */`
  #ifdef USE_LOGDEPTHBUF
  
  	#ifdef USE_LOGDEPTHBUF_EXT
  
  		vFragDepth = 1.0 + sqrt(gl_Position.z * gl_Position.z + modelW * modelW);
  		vIsPerspective = float( isPerspectiveMatrix( projectionMatrix ) );
  
  	#else
  
  		if ( isPerspectiveMatrix( projectionMatrix ) ) {
  
  			gl_Position.z = log2( max( EPSILON, gl_Position.w + 1.0 ) ) * logDepthBufFC - 1.0;
  
  			//gl_Position.z *= gl_Position.w;
  
  		}
  
  	#endif
  
  #endif
  `;
  