Debugging Your OpenGL Code // Tips & Tricks!

In this video I describe several methods that you can use in order to debug your OpenGL code, on the application side as well as on the shader side.
If you are not familiar with STB image you can check out my texture mapping tutorial at: • Basic Texture Mapping ...
Get the stb_image_write.h from my git repo below or from the original location: github.com/nothings/stb/blob/...
Online resource on debugging: learnopengl.com/In-Practice/D...
Make sure to watch all the previous tutorials in the "OpenGL For Beginners" playlist at • OpenGL for Beginners
Please visit ogldev.org to see more of my tutorials on modern OpenGL.
Link to source: github.com/emeiri/ogldev/
OpenGL 4.6 specification: www.khronos.org/registry/Open...
Feel free to comment below.
Timecodes
0:00 Intro
0:34 Method #1: glGetError()
3:49 Method #2: Debug Context
9:09 Method #3: External Tools
12:25 Method #4: Geometry first, pixel second
15:11 Method #5: Use the framebuffer for step by step debugging
16:57 Method #6: Read the framebuffer values
19:12 Conclusion
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Credits:
Video by cottonbro from Pexels
Video by Artem Podrez from Pexels
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Video by Mikhail Nilov from Pexels
Image by Clker-Free-Vector-Images from Pixabay
Image by Gustavo Rezende from Pixabay
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Sounds effect by Patricia Celso (youtube)
Sound effects by CLEREMTV (youtube)
Music: "Behold the Sun" by Topher Mohr and Alex Elena (youtube audio library)
Enjoy,
Etay Meiri
#opengl #ogldev #opengtutorials

[@onogrirwin]

holy shit this works so much better than the ole "Stare at the monitor until random quantum fluctuations results in the solution manifesting itself to you" method.

[@OGLDEV]

The quantom fluctuations based debugging tutorial is planned for the future ;-)

[@FrankGennari]

This tutorial was very useful, thanks! I've been working with OpenGL for years now and some of these techniques are ones I wasn't aware of or haven't thought of.

[@OGLDEV]

You're welcome!

[@serheiartuh8308]

I’ve been working with OpenGL for years. Debugging this black box is always a rocky road. Thank you for this tutorial, I found out a lot of new.

[@OGLDEV]

Great, thanks :-)

[@kumu2024]

I don't remember exactly how I found you. I had a BIG problem as I am learning OpenGL (modern). But your video and the comment down saved me and I could after some days find all issues I had. So, thank you very much.. If I could find this video earlier for sure I could resolve my issues also earlier. Thank you very much.

[@OGLDEV]

Glad it helped!

[@user-ub7zn9ls2f]

You saved a tonns of hours for me, thx

[@OGLDEV]

Glad to hear :-)

[@TaliPerry1]

Well done! Great video!

[@OGLDEV]

Thanks!

[@lucpena]

Thank you for this video!

[@OGLDEV]

Glad you like it :-)

[@battosaijenkins946]

Very useful thank you sir! 👍

[@OGLDEV]

Thanks for watching!

[@PaulEmsley]

This is great! I wish I'd seen it 2 years ago :-)

[@OGLDEV]

Me too! I wish I started earlier ;-)

[@Agent_Ax]

Thanks, this would be useful!

[@OGLDEV]

Glad you think so!

[@VictorGordan]

Very nice thumbnail!

[@OGLDEV]

Thanks bro!

[@gokalpates1567]

Thanks for ur video. I really recomend renderdoc to people who encounter problems. It is awesome.

[@OGLDEV]

Thanks for the tip!

[@kumu2024]

Gökalp, cok tesekkur abim. You saved me really. Thanks

[@gokalpates1567]

@@kumu2024 You are welcome :)

[@user-mu8kp6mm4q]

wonderful couse

[@OGLDEV]

Thanks!

[@PaCCKal]

My compiler can't resolve glDebugMessageCallback() and glDebugMessageControl(). Do I need some additional package?

[@OGLDEV]

These functions were introduced in OpenGL 4.3. What OS are you using? Did you setup GLEW correctly?

[@MrFacciolone]

I could not install APITRACE, it seems the package used to exist but not anymore, on install I get "unable to locate package" and even looking apitrace up in the ubuntu repository gives no result. I tried first to install it by cloning the git repository and following instructions, it installed without problem and the apitrace command works, but the command for gui qapitrace isn't available anyway. Same as with apitrace, the bash suggest installing the apitrace-gui package that no longer exists. I looked into it in docs and found out that Qt version 5.2.1+ is required, but I struggle to find a way to install it.

[@MrFacciolone]

After some more digging I find out a way to install QT5, supposedly the problem was due to ubuntu 21.04+ missing qt5 packages.. after that I could finally reinstall apitrace with the gui: Now it works! :) Extremely useful tool I am amazed, makes it a lot more easy to understand what's going on

[@OGLDEV]

That's great to hear. I was just about to suggest that cmake must have found that you are missing a package that prevents it from installing the gui. It's unfortunate that it is no longer being maintained but I still find it very useful for development. Hopefully I'll be able to find some time to learn the tools by NVIDIA/AMD/Intel.

[@MrFacciolone]

@@OGLDEV Yeah but it's straightforward so it requires no learning curve, and you can dissect a trace with just a couple commands from the bash. Overall I see no reason to switch until apitrace seriously starts lagging behind maintenance-wise. As always, great tutorial. Expecially the youtube version, it's the best OpenGL series of tutorials out there, it allows to build a very well coded general purpose framework, and this helps greatly in following the tutorial because it's not just self-serving excercises, the code used for this tutorial is already very well suited to run big scale applications with just a few changes. And it goes without saying, the most useful alternative tutorials I found are walltexts of code with interspersed explications, while yours has working demos, code explanations and video. Thanks for the series

[@OGLDEV]

@@MrFacciolone You're welcome :-)

[@glowiever]

renderdoc won't work unless with gl context 3.2. my opengl app is using gles 2.0 :( I'll check apitrace

[@OGLDEV]

According to the website apitrace supports GLES 1.0-3.0. Hopefully it will work.

[@MrMariozzz78]

can i use freeglut with opengl 2.0 o more with glsl language? o it work just with glfw?

[@OGLDEV]

Sure, FreeGLUT supports all versions of OpenGL.

[@MrMariozzz78]

@@OGLDEV i need Glew o glad too or glut is enough?

[@OGLDEV]

You need either GLEW or GLAD to load the functions pointers. I'm using GLEW. People who follow learnopengl.com usually go with GLAD because this is what the website is using.

[@MrMariozzz78]

@@OGLDEV ok thank ,but i don't know how istall glad on codeblock it generata many version of opengl on website

[@OGLDEV]

Hopefully you can find an answer on learnopengl.com or on one of the forums. I've never tried to use GLAD myself. Was always happy using GLEW so I never tried an alternative.

[@prezadent1]

Glut hasn't been widely used in several years. Neither has header guards.

[@OGLDEV]

Thanks for the feedback. The windowing library is not that important. My tutorials should work in both FreeGLUT and GLFW. Regarding header guards - I actually still find myself using them on older code every now and then when I need a quick-n-dirty error check. I want the people who are watching the videos to have all the options available and make their own choice, though debug output is definitely the way to go.

[@kermalis]

Wow I've been using the DebugMessageCallback without "DebugOutputSynchronous" for months, thanks for that lol

[@OGLDEV]

You're welcome :-)