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Replicon

OpenGL OpenGL3 and NeHe relevance

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Hi, To avoid making someone angry in the OpenGL forum, I'm posting this here :-) I'm still very much an OpenGL newbie (slowly working my way through the excellent NeHe tutorials, using SDL + OpenGL). I read that OpenGL3 really fundamentally changes the API. The question is, just how fundamental is this change? That is, is the majority of the NeHe tutorial work pretty much obsolete, or do the changes only kick in for the more advanced shader stuff? I've only gotten to maybe lesson 6-7 and took a break for other stuff, so starting over with a very different API isn't the end of the world hehe... Also, if my video card supports OpenGL2, will everything I do with the new 3.0 API be software-only, or does it have a good conversion layer to still use the OpenGL2-based hardware acceleration? cheers!

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I don't see why this would make anyone mad -- and it's offtopic for the beginners forum. So I'm moving it to the OpenGL forum.

A good chunk of the early NeHe stuff uses immediate mode, which will be going away in GL3. All of that will be obsolete, then. I haven't see too much of the GL3 API details, but I'd bet there will be fairly signifigant API break.

OTOH, GL3 has been on the horizon for a while now. I haven't seen anything to make me believe it will actually show up soon, so there's no reason to worry about learning the "wrong stuff" (the underlying concepts will transfer between GL and GL3 as they do between GL and D3D anyway).

OTOH (again), I don't think NeHe is a particular good learning resource anyway. The code's pretty bad, and the explanations of the fundamentals are not sufficient enough for me.

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The interface is changing. They haven't said what the new interface will be so that is a very hard question to answer at the moment. It should be fairly similar as it will provide the exact same abilities as the current release of opengl. Don't worry about it to much and focus on learning graphics programming, while using opengl as a tool. Don't learn opengl and not pay attention to the math going on in the background.

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Original post by jpetrie
I don't see why this would make anyone mad


I figured, while my searches didn't turn up anything, it was probably asked before, because it seems like a fairly obvious question to ask :-)

Quote:
OTOH (again), I don't think NeHe is a particular good learning resource anyway. The code's pretty bad, and the explanations of the fundamentals are not sufficient enough for me.


You have a lot of hands! I agree, the code is fairly 'bleh', and I wouldn't exactly use it as an example of good architecture by any stretch. And I always go to the official API docs with every new API call he makes. It's just a decent way of getting shown around in a modular fashion. If you can recommend a better source from which to learn it in a way that doesn't feel like a reference manual, I'm all ears.

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Quote:
Original post by Replicon
You have a lot of hands! I agree, the code is fairly 'bleh', and I wouldn't exactly use it as an example of good architecture by any stretch. And I always go to the official API docs with every new API call he makes. It's just a decent way of getting shown around in a modular fashion. If you can recommend a better source from which to learn it in a way that doesn't feel like a reference manual, I'm all ears.


I would reccomend the red book (OpenGL Programming guide, mentioned in this forum FAQ) over NeHe anytime.

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Quote:
Original post by Replicon
I read that OpenGL3 really fundamentally changes the API. The question is, just how fundamental is this change? That is, is the majority of the NeHe tutorial work pretty much obsolete, or do the changes only kick in for the more advanced shader stuff? I've only gotten to maybe lesson 6-7 and took a break for other stuff, so starting over with a very different API isn't the end of the world hehe...


OpenGL3.0 is going to be a totally breaking API change, consider it a fresh start for OpenGL.
That said, there are a number of things to consider;
1) GL3 has been 'soon' for around 6 months now and the ARB has gone silent on us again so we aren't expecting it any time soon (the lack of OpenGL at GDC doesn't bode well either).
2) Even if GL3 was released tomorrow everyone pretty much expects a 6month lead time before drivers are stable.
3) GL2.x isn't going to vanish over night. You'll still be able to use GL2.1 in it's current form for some time to come (years), just dont' expect any updates or new extensions for it; what you've got is what you've got.

Now, as for learning, personally I swear by the Red Book aka OpenGL programmers guide. NeHe got me intrested but it was the Red Book and alot of poking about which got me the rest of the way.

Quote:

Also, if my video card supports OpenGL2, will everything I do with the new 3.0 API be software-only, or does it have a good conversion layer to still use the OpenGL2-based hardware acceleration?


GL3.0 is, effectively, the feature set of GL2.0 with a new, cleaner, API.

What this means in real terms is that as long as you've got at least a Nvidia GFFX or a ATI 9500 graphics card you should be able to support it (as to if either company will make it work on their hardware or not is another matter) as the 'lowest end' has been fixed to supporting DX9 level features. However it will be in hardware, like GL2.x is now.

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Since you already reference the API as you go through the NeHe tutorials and though the Red book is undoubtly a good resource, I would recommend "Advanced Graphics Programming using OpenGL, McReynolds/Blythe". This book is better at explaining the concepts behind a lot of more modern techniques rather than going through the API from A-Z like Red Book / OpenGL Superbible. Much of the contents of the Red book can be found online at http://www.opengl.org/sdk/docs. Another good book down the same alley is "Realtime Rendering, Moller/Haines" with the difference that this discusses the concepts without going into any API details. I feel that these two books have a better chance of being useful after OpenGL 3 is introduced and you can probably pick up an updated OpenGL Superbible / Red Book when the specifications have been revealed.

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I also started learning OpenGL using the NeHe-tutorials, but i bought the red book and later also the orange book. The red book is in my opinion (as others here have stated as well) the best way to learn OpenGL. Its just excellent, as well as the orange book.

EDIT: If you learn OpenGL and the techniques it uses, moving between OGL2 and OGL3 shouldn't be very difficult, just read some API specs.

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