code: function (oldData) {
      var data = this.data;
      var material = this.material;
      var oldDataHasKeys;
  
      // Base material properties.
      material.alphaTest = data.alphaTest;
      material.depthTest = data.depthTest !== false;
      material.depthWrite = data.depthWrite !== false;
      material.opacity = data.opacity;
      material.flatShading = data.flatShading;
      material.side = parseSide(data.side);
      material.transparent = data.transparent !== false || data.opacity < 1.0;
      material.vertexColors = parseVertexColors(data.vertexColors);
      material.visible = data.visible;
      material.blending = parseBlending(data.blending);
  
      // Check if material needs update.
      for (oldDataHasKeys in oldData) { break; }
      if (oldDataHasKeys &&
          (oldData.alphaTest !== data.alphaTest ||
           oldData.side !== data.side ||
           oldData.vertexColors !== data.vertexColors)) {
        material.needsUpdate = true;
      }
    }
docs: Set and update base material properties.
  Set `needsUpdate` when needed.