ios - How can I draw the same GL_RENDERBUFFER content to two different CAEAGLLayer? -

in project try render content opengl, work fine in single view. want use 1 eaglcontext simultaneously render same gl_renderbuffer content 2 views, has different frame.

i try seems - renderbufferstorage:fromdrawable: can't bind 2 caeagllayer.how can work? appreciate!

- (void)setupframebuffer {     glgenrenderbuffers(1, &maincolorrenderbuffer);     glbindrenderbuffer(gl_renderbuffer, maincolorrenderbuffer);      //****************it can't work***********     [maincontext renderbufferstorage:gl_renderbuffer fromdrawable:(id<eagldrawable>)anotherglview.layer];     [maincontext renderbufferstorage:gl_renderbuffer fromdrawable:(id<eagldrawable>)self.layer];     //****************************************      glgetrenderbufferparameteriv(gl_renderbuffer, gl_renderbuffer_width, &mainbufferwidth);     glgetrenderbufferparameteriv(gl_renderbuffer, gl_renderbuffer_height, &mainbufferheight);     glgenframebuffers(1, &mainframebuffer);     glbindframebuffer(gl_framebuffer, mainframebuffer);     glframebufferrenderbuffer(gl_framebuffer, gl_color_attachment0, gl_renderbuffer, maincolorrenderbuffer);     glframebufferrenderbuffer(gl_framebuffer, gl_depth_attachment, gl_renderbuffer, maindepthrenderbuffer);     unsigned status = glcheckframebufferstatus(gl_framebuffer);     nsassert(status == gl_framebuffer_complete, @"");     glviewport(0, 0, mainbufferwidth, mainbufferheight); }