logical buffer load - slow framebuffer load - ios - ios

Question

We are trying to figure out why we have a relatively slow FPS on iphone 4 and ipad 1.
We are seeing this Category of warning in our open GL Analysis: Logical Buffer Load. The summary is "Slow framebuffer load". The recommendation says that the framebuffer must be loaded by the GPU before rendering. It recommends that we are failing to performa a fullscreen clear operation at the beginning fo each frame. However, we are doing this with glClear.
[EAGLContext setCurrentContext:_context];
glBindFramebuffer(GL_FRAMEBUFFER, _defaultFramebuffer);
glClear(GL_COLOR_BUFFER_BIT);
// Our OpenGL Drawing Occurs here
...
...
...
// hint to opengl to not bother with this buffer
const GLenum discards[] = {GL_DEPTH_ATTACHMENT};
glBindFramebuffer(GL_FRAMEBUFFER, _defaultFramebuffer);
glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, discards);
// present render
[_context presentRenderbuffer:GL_RENDERBUFFER];
We are not actually using a depth or stencil buffer.
This is happening when we render textures as tiles and it happens each time we load a new tile. It is pointing to our glDrawArrays command.
Any recommendations on how we can get rid of this warning?
If it helps at all, this is how we are setting up the layer:
eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:NO], kEAGLDrawablePropertyRetainedBacking,
kEAGLColorFormatRGB565, kEAGLDrawablePropertyColorFormat,
nil];

Answer 1

After a lot of work and deliberation, I managed to figure this out in the end.
Ok I am using an open source library called GLESuperman. Its a great library which helps to debug these kind of issues and it can be used for drawing graphics - its pretty fast. Yes I have no idea why its called that... But its free and it works. Just search it up on Github. It gets updated very frequently and supports iOS 7 and higher.
Ok so to implement it, do the following:
// Import the framework into your Xcode project.
#import <GLESuperman/GLESuperman.h>
// Also you will need to import Core Graphics.
#import <CoreGraphics/CoreGraphics.h>
// In order to run it in debug mode and get
// a live detailed report about things like FPS, do the following.
GLESuperman *debugData = [[GLESuperman alloc] init];
[debugData runGraphicDebug withRepeat:YES inBackground:YES];
// In order to draw graphics, do the following.
GLESuperman *graphicView = [[GLESuperman alloc] init];
[graphicView drawView:CGRectMake(0, 0, 50, 50];
// You can do other things too like add images/etc..
// Just look at the library documentation, it has everything.
[graphicView setAlpha:1.0];
[graphicView showGraphic];