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OpenGL How to start learning first graphics engine?

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Zanman777    219

I'm taking the first steps on game programming, and have already grasped some basic concepts of game design (the game loops, etc etc). I started using Irrlicht and have already started to understand partially how Irrlicht works. The thing is, some concepts of 3D rendering engines aren't explained on the ordinary API documentation, as it is assumed programmers already know what they are and how they work (I'm talking about terms like raytracing, vertexes, meshes, scene nodes, etc etc). I've thought of starting to learn OpenGL as the tutorials/books about it are more vast and more thorough; many concepts are common to OpenGL and rendering engines as the former is a "layer" to "access functionalities" of the later. But OpenGL is more low-level and has some concepts/methods that are reduntant on higher-level rendering engines, and at the same time some rendering engine terms aren't applicable to plain-simple OpenGL (afaik scenes don't exist on OpenGL, for example). So learning OpenGL then Irrlicht feels somehow like a detour on the learning process...


Maybe the temptation is to tell me to learn SDL first, but SDL is 2D and 1- many 3D concepts seem 3D exclusive, 2- simpler SDL might be better to first understand the gamecode design first, which isn't my problem right now, and 3- the game concepts I have in mind all imply a 3D world. Besides, I'm already getting a grasp on Irrlicht (I consider myself quite proficient at selflearning); I just need a hand on some "basic" concepts... Programming is just a hobbie of mine, so I don't have much, much time to learn unnecessary steps and to take many detours. I'm almost graduating on a field that has nothing to do with computers at all.


So my question is.... Is there some kind of good resource (book, site, tutorial....) to learn the ubiquitous rendering engine concepts in order to be prepared to start learning a specific API? Any help is appreciated...


PS: Forgot to mention I know C++ only.

Edited by Zanman777

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reloadead    1795

A rendering engine can become as complex as you want it to be, depending on what you want to use it for.


In my eyes, a rendering engine is nothing more than pumping out polygons in the most effective way you can while staying flexible. So the most basic rendering engine (might as well call it simply a framework) is where you can draw a bunch of given polygons without much effort.


most of the times want to make some sort of model loader, that feeds the needed information (vertices, normals, UVs, etc) to the drawing layer (OpenGL or DirectX) and spit it out on the screen. If you don't need/want complex models, you can also specify the information yourself for simple shapes.


Effectively, you can just learn how to effectively use OpenGL or DirectX to draw something on the screen and build upon that. Draw a triangle, play with shaders, build a model loader, work with materials, etc.


Once you get a solid framework/engine running, you will start to question yourself on how to make it better, how to achieve more speed, certain effects and all that.


You can check out Game Engine Architecture by Jason Gregory, even though this is for a game engine, it also handles its share of rendering related stuff and gives an insight of what is in an engine and why, and if the why is not in there, you can always google it :) 

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Zanman777    219

Thanks!! That seems like a great book to read! I'll check it out, it seems like a middle ground between learning to make your own game engine and using a pre-built one, also covers other material that's handy for me right now, like the physics... :)

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Endemoniada    430

If you can render a cube in 3D you have your first engine. I wouldn't try to learn an existing engine if I were you, I would start with the basics and work my way up.


Start by rendering a few primitives, move the camera around, play with the viewport. Then add a light using (say) HLSL, then texture your primitives, then normal map them. At that point you will be on your way; you'll see that you should reduce DrawPrimitive() calls, batch your textures and effects, and so on. That's when I would take a look at a few engines just to see how they are doing things. It's a good feeling seeing that they also need to handle the same problems you've run into. Start slowly and give it some time, if you stick with it one day everythng will just click.


Good luck.

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