       uniform float baseVoxel;
       uniform float minParticleSize;
       uniform int   showRadius;
+      uniform float devicePixelRatio;
       varying vec3 vColor;
       attribute float size;
 

      showRadius :
        type : "i"
        value : 1

    attributes =
      size :

          vColor = color;
          if (showRadius == 1)
            gl_PointSize = max(
              size / zoomFactor / baseVoxel,
              minParticleSize ) * devicePixelRatio;
          else
            gl_PointSize = minParticleSize;
          gl_Position = projectionMatrix * mvPosition;
