code: func (c *drawTrianglesCommand) Exec(indexOffset int) error {
  	// TODO: Is it ok not to bind any framebuffer here?
  	if c.nindices == 0 {
  		return nil
  	}
  
  	c.dst.image.SetAsDestination()
  	c.src.image.SetAsSource()
  	if err := theGraphicsDriver.Draw(c.nindices, indexOffset, c.mode, c.color, c.filter, c.address); err != nil {
  		return err
  	}
  	return nil
  }
docs: // Exec executes the drawTrianglesCommand.