docs: function ShockwaveFilter()
  {
      core.AbstractFilter.call(this,
          // vertex shader
          null,
          // fragment shader
          fs.readFileSync(__dirname + '/shockwave.frag', 'utf8'),
          // custom uniforms
          {
              center: { type: 'v2', value: { x: 0.5, y: 0.5 } },
              params: { type: 'v3', value: { x: 10, y: 0.8, z: 0.1 } },
              time: { type: '1f', value: 0 }
          }
      );
  }