Texture,
      u_matrix: m4.identity(),
    });

    // calls gl.drawArrays or gl.drawElements
    twgl.drawBufferInfo(gl, quadBufferInfo);
    
    // ---------
    
    // draw previous cube texture into current cube texture
    {
      twgl.setUniforms(programInfo, {
        u_tex: fbiA.texture,
        u_matrix: m4.scaling([0.8, 0.8, 1]),
      });
      twgl.drawBufferInfo(gl, quadBufferInfo);
    }
  }    
    
  function drawTexturedCubeToTextureA(time) {
    // ---------   
    // draw cube to "new"