Godot引擎，将渲染目标设置为opengl-es framebuffer

Question

最近，我专注于和戈多一起玩。当我尝试将渲染目标设置为opengl-es帧缓冲区时，我遇到了问题。我试过RasterizerGLES2::set_base_framebuffer，但它不起作用。

我的示例代码：

// create framebuffer and attach texture
glGenFramebuffers(1, &my_target_framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, my_target_framebuffer);

glGenTextures(1, &my_target_texture);
glBindTexture(GL_TEXTURE_2D, my_target_texture);
glTexParameteri(...);
glTexImage2D(...);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, my_target_texture, 0);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);

// clear to RED
glClearColor(1, 0, 0, 1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glBindFramebuffer(GL_FRAMEBUFFER, 0);

// then call set_base_framebuffer, something like:
RasterizerGLES2::set_base_framebuffer(my_target_framebuffer, 
Vector2(my_target_width, my_target_height));

根本不起作用，my_target_framebuffer总是RED（不会绘制到my_target_framebuffer），屏幕闪烁。

plz help！

顺便说一下，我使用的是Godot 2.1