renderer

# 
# cocos2d-x v3.0 renderer
#
# for further info read: https://docs.google.com/document/d/17zjC55vbP_PYTftTZEuvqXuMb9PbYNxRFu0EGTULPK8/edit#heading=h.3kpkd5ktk6p1
#


# Populates the VBO.
# It stops if the command is a group or if
#  the VBO's capacity is not enough for the current Quad Command
# commands: list of commands
# returns: command that needs to be parsed next
def populate_vbo( ctx ):

  # only iterate from the previous command to the last one
  range = ctx.get_commands[ctx.last_command] : ctx.get_commands[-1]
  for command in range:
    if command.is_group():
      ctx.last_command = command
      break
 
    if command.is_quad():
      if vbo.enough_capacity( command.quad_size() )
        vbo.append( command.get_quads )
      else
        ctx.last_command = command
        break
  
# Creates a new context for a new group command
def new_context( command ):
  ctx.commands = command.get_commands()
  ctx.set_gl_context = command.set_gl_context
  ctx.unset_gl_context = command.unset_gl_context
  ctx.last_command = 0
  ctx.firt_time = True
  return ctx


# Main function
# Parses, sorts, etc.
# ctx: renderer context 
def parse_commands( ctx ):
  
  # draws elements that weren't drawn
  if ctx.first_time:
    global_vbo.flush()
    ctx.set_gl_context()
    sort( ctx.get_commands() )
    ctx.first_time = False
  
  populate_vbo( ctx )
  
  for command in ctx.get_commands():
    # VBO full ?
    if command == ctx.last_command
      parse_commands( ctx )

    elif command.is_group():
      # start new recursion
      parse_commands( new_context( command ) )

      # Start from last point
      parse_commands( ctx )
    
    # Render is optimized for Quads
    elif command.is_quad():
      if ctx.current_material_id != command.get_material_id():
        ctx.current_material_id = command.get_material_id()
        command.set_material()
        gl_draw( global_vbo, ctx.last_vbo_index, ctx.current_vbo_index )
        ctx.last_vbo_index = ctx.current_vbo_index

  ctx.unset_gl_context()


#
# Main entry. 
# It just calls the recursive fuction
#
def renderer_start():
  start = RenderCommandGroup( main_list, glClear, None)
  parse_commands(new_context(start))
  global_vbo.flush()