docs: function PixelateFilter()
  {
      core.AbstractFilter.call(this,
          // vertex shader
          null,
          // fragment shader
          fs.readFileSync(__dirname + '/pixelate.frag', 'utf8'),
          // custom uniforms
          {
              dimensions: { type: '4fv',  value: new Float32Array([0, 0, 0, 0]) },
              pixelSize:  { type: 'v2',   value: { x: 10, y: 10 } }
          }
      );
  }