Render to texture failing

Apprentice

Posts: 14
Joined: 2010.08

Post: #1

Aug 31, 2010 — 09:58 PM

I am trying to setup a FBO so I can render to a texture. It works fine in simulator but fails on iPhone 3G with the message "failed to make complete framebuffer object 8cd6". The error code is GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_OES.

Here is the code

Code:

GLuint framebuffer;

glGenFramebuffersOES(1, &framebuffer);

glBindFramebufferOES(GL_FRAMEBUFFER_OES, framebuffer);

GLuint texture;

glGenTextures(1, &texture);

glBindTexture(GL_TEXTURE_2D, texture);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 320, 480, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);

glFramebufferTexture2DOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_TEXTURE_2D, texture, 0);

glBindTexture(GL_TEXTURE_2D,0);

GLuint depthRenderbuffer;

glGenRenderbuffersOES(1, &depthRenderbuffer);

glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);

glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, 320, 480);

glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);

GLenum status = glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES);

if(status != GL_FRAMEBUFFER_COMPLETE_OES)

    NSLog(@"failed to make complete framebuffer object %x", status);

I've followed the way it's done on Apple's website topic Using Framebuffer Objects to Render to a Texture.

I have researched this for hours now and cannot figure out why it's failing.

headkaze

Apprentice

Posts: 14
Joined: 2010.08

Post: #2

Aug 31, 2010 — 11:58 PM

Even putting this code into a blank OpenGL ES template in XCode it fails on the 3G (running iOS 4.0.1). Can someone please help?

mariocaprino

Member

Posts: 23
Joined: 2010.08

Post: #3

Sep 1, 2010 — 12:23 AM

Having a quick look through your code I believe you can't create a Non-Power-Of-Two textures on the iPhone. Try putting a glGetError() after your glTexImage2D() to test if it fails.

There might be other errors but hopefully that will give you a head start.

The Monkey Hustle - Now available on the App Store!

headkaze

Apprentice

Posts: 14
Joined: 2010.08

Post: #4

Sep 1, 2010 — 12:32 AM

Oh wow, what an idiot I am. Thankyou so much mariocaprino that was it. I can't believe I have spent so much time trying to figure this out!

arekkusu

Sage

Posts: 1,231
Joined: 2002.10

Post: #5

Sep 1, 2010 — 01:15 AM

More specifically, you can't create NPOT textures on MBX devices. You can on SGX.

headkaze

Apprentice

Posts: 14
Joined: 2010.08

Post: #6

Sep 1, 2010 — 01:44 AM

How can I check if I need to make the texture POT? Any glGetIntegerv() I can check?

Another problem I've encountered is when I switch back to my normal rendering the depth buffer is no longer working.

I have this code

Code:

if(m_textureRenderer->IsActive())

{

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, m_textureRenderer->GetFrameBuffer());

    glBindRenderbufferOES(GL_RENDERBUFFER_OES, m_textureRenderer->GetDepthBuffer());

}

else

{

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, m_defaultFramebuffer);

    glBindRenderbufferOES(GL_RENDERBUFFER_OES, m_depthRenderbuffer);

}

If I don't active the texture rendering then it renders fine, it's only when I go to texture rendering then back again that the depth buffer no longer works.

Looks like all I need is

Code:

if(m_textureRenderer->IsActive())

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, m_textureRenderer->GetFrameBuffer());

else

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, m_defaultFramebuffer);

And to restore the default depth buffer

Code:

glBindRenderbufferOES(GL_RENDERBUFFER_OES, m_depthRenderbuffer);

glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, m_depthRenderbuffer);

arekkusu

Sage

Posts: 1,231
Joined: 2002.10

Post: #7

Sep 1, 2010 — 08:23 PM

(Sep 1, 2010 01:44 AM)headkaze Wrote: How can I check if I need to make the texture POT?

Check for the APPLE_texture_2D_limited_npot extension, as listed in the platform notes.

Quote:I have this code

What are you expecting glBindRenderbuffer to do here?

headkaze

Apprentice

Posts: 14
Joined: 2010.08

Post: #8

Sep 1, 2010 — 09:47 PM

(Sep 1, 2010 08:23 PM)arekkusu Wrote: What are you expecting glBindRenderbuffer to do here?

I replied to my own post which seems to add to the previous post with a HR between them.

What I wanted to do was switch my game from rendering to the screen to a texture (for a transition) then back again.

I've already figured it out, I just had to add the glFramebufferRenderbufferOES call instead of just binding it otherwise the depth buffer does not work.

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