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MrJoshL

OpenGL
How Could I Learn OpenGL ES 3.0?

5 posts in this topic

I am new to graphics programming, but am by no means new to programming. I might not be the seasoned veteran and trusted expert on C/C++, but I think my knowledge is sufficient. I am currently reading the book [u]Real Time Rendering, 3rd Edition[/u], and while it is very helpful, it does not teach a graphics API (I knew it didn't beforehand, and didn't expect it to). Seeing as OpenGL ES 3.0 spec was just released, I thought, "Why would I learn ES 2 when I can just learn the fully PC-compatible ES 3?" So, how would I learn it, when the specification was just ratified fairly recently, read the specification? And, while I'm at it, how do you program with OpenGL? I realize that it is a specification and not a full API, but I can't say I know anything about how to implement it.

P.S: Sorry for the annoying n3wb question [img]http://public.gamedev.net//public/style_emoticons/default/wink.png[/img]
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[quote name='MrJoshL' timestamp='1345174178' post='4970410']
Why would I learn ES 2 when I can just learn the fully PC-compatible ES 3
[/quote]

Because what matters are the underlying concepts. The core graphics concepts of sending geometry and creating shaders to process the geometry data probably hasn't changed much.

A common newbie mistake is hearing that professionals are using a Shiny Tool and think that if they use the Shiny Tool that it will make them like professional in a meaningful way. It won't. What you need to do as a new programmer is make sure you grasp the foundational concepts of graphics programming and can apply them in a well structured and scalable way.
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I agree that you should learn the underlying concepts, I would check out the nvidia opengl sdk, it has a wealth of knowledge (but you must understand that those are quicky demos and if you wanted a full engine you wouldn't mimic some of the things they do).

I also highly suggest checking out Humus' Framework3, It is a great reference for looking at the ins and outs of the various apis.
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@Lazy Foo I am not a "that's a shiny tool" person, or I would be using OpenGL 4.3. I am using OpenGL ES 3.0. I was going to do everything in OpenGL ES 2.0, but my main reason is functionality not "I want to be a shiny professional," because frankly, I have no interest of being a professional programmer in the graphics field or even a professional programmer at all (I'm getting an engineering degree). I just wanted (like almost everyone else) to have minimal code changes across different machines. That's all. I just wanted to know how I would learn such a recent specification. Should I read ES 2.0 books? Should I read the ES 3.0 specification? Both? That is all. And I might be a far shot from expert, but I wouldn't say I'm a complete beginner in C programming. I know how to do a few things at least.

@AverageJoeSSU Is the nVidia OpenGL SDK a full implementation of OpenGL? Does it come with a shader compiler?
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[quote name='MrJoshL'']Seeing as OpenGL ES 3.0 spec was just released, I thought, "Why would I learn ES 2 when I can just learn the fully PC-compatible ES 3?"[/quote]

OpenGL ES 2.0 is a good starting point because it is forward compatible with OpenGL ES 3.0, meaning the applications you develop for OpenGL ES 2.0 will work (with minor modifications in the vertex and fragment shading code) on OpenGL ES 3.0, as well as desktop OpenGL 2.1, OpenGL 3.x and OpenGL 4.x.

[quote name='MrJoshL'']So, how would I learn it, when the specification was just ratified fairly recently, read the specification?[/quote]

If you have a graphics card that supports OpenGL 4.3 (NVIDIA has released OpenGL 4.3 beta drivers), you can use an OpenGL ES 3.0 emulator. The Adreno 3.0 SDK for Windows and the Mali Developer SDK for Windows include an OpenGL ES 3.0 emulator. If you do not have an OpenGL 4.3 compatible graphics card, you could artificially restrict yourself to the OpenGL 3.3 core API to get an idea of what OpenGL ES 3.0 programming would be like.

If you are doing mobile development, OpenGL ES 3.0 for the iPhone likely will not be available until iOS 7 next fall, possibly later (Apple didn't support OpenGL ES 2.0 until 2 years after it was released in 2007). For Android, it's said to be already available from select vendors who sell debugging devices, but it probably won't be available for the mainstream user until early next year.

[quote name='MrJoshL'']And, while I'm at it, how do you program with OpenGL? I realize that it is a specification and not a full API, but I can't say I know anything about how to implement it.[/quote]

OpenGL is normally implemented by the graphics hardware vendors.
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[quote name='MrJoshL' timestamp='1345174178' post='4970410']
I am new to graphics programming, but am by no means new to programming. I might not be the seasoned veteran and trusted expert on C/C++, but I think my knowledge is sufficient. I am currently reading the book [u]Real Time Rendering, 3rd Edition[/u], and while it is very helpful, it does not teach a graphics API (I knew it didn't beforehand, and didn't expect it to). Seeing as OpenGL ES 3.0 spec was just released, I thought, "Why would I learn ES 2 when I can just learn the fully PC-compatible ES 3?" So, how would I learn it, when the specification was just ratified fairly recently, read the specification?[/quote]

Unless you have a good real-world ES3 device or platform to run your code on, I think it would be unnecessarily difficult to learn Open GL via jumping straight into its newest, only-just released iteration instead a version that currently sees vastly more widespread use. There's a wealth of easy and quick tutorials around the web for learning Open GL ES2, and I would highly recommend supplementing any reading you do with a good amount of tinkering to see what's what. I would expect anything you learn in ES2 to carry across to ES3, and in some respects being familiar with the history of an API can lead to a more robust grasp of its newer iterations.

[quote name='MrJoshL' timestamp='1345174178' post='4970410']
And, while I'm at it, how do you program with OpenGL? I realize that it is a specification and not a full API, but I can't say I know anything about how to implement it.[/quote]

It's really just a matter of instructing the GPU to perform certain tasks, provided with certain data. In a nutshell, you prepare buffers (this is already a complex area) for various processes - e.g. the one that'll be presented to a device's display for starters. Next, you prepare the shader programs that tell the GPU what to do with the data you'll be throwing at it, and lastly you supply vertex, uv, color, and various other information to the GPU so that it can be rendered.

^ nb: above is an extreme oversimplification - only intended to provide a rough idea. Each part of that process can run extremely deep in its complexity, depending on what you want to do.

Half the battle in OpenGL is often finding ways to create an image efficiently with minimal wasted/repeated/redundant effort on the hardware's part, but to start with, just get some stuff on your screen and learn the anatomy of the whole process incrementally.
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