code: function (renderer) {
  
          var _gl = renderer.gl;
          var cache = this._cache;
  
          cache.use(renderer.__uid__);
  
          var renderBuffer = cache.get(KEY_RENDERBUFFER);
          if (renderBuffer) {
              _gl.deleteRenderbuffer(renderBuffer);
          }
          var frameBuffer = cache.get(KEY_FRAMEBUFFER);
          if (frameBuffer) {
              _gl.deleteFramebuffer(frameBuffer);
          }
          cache.deleteContext(renderer.__uid__);
  
          // Clear cache for reusing
          this._textures = {};
  
      }
docs: Dispose
  @param  {WebGLRenderingContext} _gl