iPhone opengl ES copy framebuffer into the renderbuffer - iphone

Question

Hy folks,
I'm working on an animation in opengl es. The animation should draw squares. This works already, but how can I copy the content from the Framebuffer into the renderbuffer, the problem is that with every frame only one square is on the display.
When I tested it in the simulator and it worked. With every new frame a knew square is drawn and the others that have been drawn already are still on the screen. But when I tested it on the device it didn't worked. The screen was just blinking.
I think this happens because my mac like every other computer is using doublebuffering and the iPhone dosen't.
Please help me.
This is how I'm setting up my Framebuffer:
- (BOOL)createFramebuffer {
glGenFramebuffersOES(1, &viewFramebuffer);
glGenRenderbuffersOES(1, &viewRenderbuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[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, &backingWidth);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
if (USE_DEPTH_BUFFER) {
glGenRenderbuffersOES(1, &depthRenderbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
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 also wrote a setupView Methode:
- (void)setupView {
glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Black Background
// glEnable(GL_DEPTH_TEST); // Enables Depth Testing
// glDepthFunc(GL_LEQUAL); // The Type Of Depth Testing To Do
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations
glViewport(0,0,backingWidth,backingHeight); // Reset The Current Viewport
glMatrixMode(GL_PROJECTION); // Select The Projection Matrix
glLoadIdentity(); // Reset The Projection Matrix
// Calculate The Aspect Ratio Of The Window
gluPerspective(45.0f,(GLfloat)backingWidth/(GLfloat)backingHeight,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix
isSetUp = YES;
}
This is my drawView Methode:
const GLfloat squareVertices[] = {
-1.0f, 1.0f, 0.0f,
1.0f, 1.0f, 0.0f,
1.0f, -1.0f, 0.0f,
-1.0f, -1.0f, 0.0f
};
[EAGLContext setCurrentContext:context];
if (!isSetUp) {
[self setupView];
}
glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
//glClear(GL_COLOR_BUFFER_BIT);
//////////////////////Variablen
float xg = -26;
float yg = 35.5;
float z = -100.0;
float abstandXg = 3.0;
float abstandYg = 3.0;
for (int i = 0; i < 26; i++) {
//arrayKoordinatenY[j] = y - abstandY * (j);
for (int j = 0; j<=17; j++) {
// glLoadIdentity();
//arrayKoordinatenX[i] = x + abstandX * (i);
//glTranslatef(arrayKoordinatenX[j],arrayKoordinatenY[i],z);
glTranslatef(xg,yg,z);
glEnableClientState(GL_VERTEX_ARRAY);
glColor4f(0.0f,0.0f,0.0f,0.0f);
glVertexPointer(3, GL_FLOAT, 0, squareVertices);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
arrayKoordinatenX[j]=xg;
xg = xg + abstandXg;
}
xg = -26.0;
arrayKoordinatenY[i]=yg;
yg = yg - abstandYg;
}
//// Here comes the Part where the squares are draw
.
.
.
/////
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

Answer 1

glMatrixMode(GL_PROJECTION); // Select The Projection Matrix
glLoadIdentity();
OK - but where is the same thing for GL_MODELVIEW ?