code: function () {
              this.sbIndex = 0;
              this.length = 0;
  
              var samplers = [];
  
              // WebGL context
              this.gl = this.renderer.gl;
  
              this.flush();
  
              this.setProjection(this.gl.canvas.width, this.gl.canvas.height);
  
              this.setViewport(0, 0, this.gl.canvas.width, this.gl.canvas.height);
  
              // Initialize clear color
              this.gl.clearColor(0.0, 0.0, 0.0, 1.0);
  
              for (var i = 0; i < this.maxTextures; i++) {
                  this.units[i] = false;
                  samplers[i] = i;
              }
              // set the quad shader as the default program
              this.useShader(this.quadShader);
              this.quadShader.uniforms.uSampler = samplers;
          }
docs: Reset compositor internal state
  @ignore