EAGLContext not work on openGLES 1 iphone os

I have a 3D project based on the EAGLView exemple from Apple.

I have a very stange bug with the context ( I think ), my context is create by using :

[context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer*)self.layer];

On init the 3D view it's work, and on layout subview, my frameBuffer is destroy an create again. But in some case, the framebuffer is not create. I have search with the debugger I have find the problem become from the context "creation":

- (BOOL)createFramebuffer
{
    NSLog(@"[EAGLVIEW] create framebuffer");

    glGenFramebuffersOES(1, &viewFramebuffer);
    glGenRenderbuffersOES(1, &viewRenderbuffer);

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);


    //////// HERE, some time the context is 0 /////////
    [context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer*)self.layer];
    //////////////////////


    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);

    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &bac开发者_开发知识库kingWidth);
    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);


    // On génère le tampon de profondeur -- bah oui, on fait de la 3D
    glGenRenderbuffersOES(1, &depthRenderbuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
    // On paramètre le tampon :
    // - avec les dimensions que l'on veut
    glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
    //glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_RGB8_OES, backingWidth, backingHeight);
    // - avec la profondeur que l'on veut
    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);


    if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES) {
        NSLog(@"failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES));
        return NO;
    }

    return YES;
}

I don't understand why it's work or not. When i have this bug, i turn my iphone for force to execute layoutSubview, and it's work. it's very strange.

what are the reason for the context not create at second and it's ok just after.

---

You have not posted the code showing how you actually created the context, just using it. Your context creation should look something like this

context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];

if (!context || ![EAGLContext setCurrentContext:context])
    return false;

And if the context is 0 (which mean nil) then you will have detected it before hand.