Hello all. New member here. I've just gotten into 3d programming. I am intermediate in C++ programming, and I know a bit of OpenGL. What I would like to do, is create an environment which functions like our own. I notice that a lot of 3d applications use polygons with image textures, and then there is application of shadows and highlights, based on the light source. Then again, that's just what I have noticed, when watching 3d movies, and playing 3d videogames. Perhaps I am wrong. I find this method to be flawed and limited, and I think I have a better way to simulate it. Let's say we create a lightsource. Let's imagine that the lightsource is the sun. I would assign an array of variables to this. These variables would be assigned to wavelengths on the electromagnetic spectrum. I would not limit the amount of wavelengths to the visible spectrum, because some other wavelengths, like ultraviolet are visible to some people and some creatures, and also because I would need these wavelengths for a project I would use this graphics theory for. There would be a few other variables, which measure distance between objects and the light source, the intensity, and so forth. I would create a formula, which calculates the value of the color at any given location. Objects would be anisotropic polygons, with colorless texture. The objects would have different polygons, for the distance of the viewpoint which is viewing it. This is something like Elder Scrolls IV: Oblivion's engine, where graphics become more detailed, as the distance between the player and the object becomes smaller. This would be to reduce the amount of computing power required to render the entire picture. Anyway, I would use the aforementioned formula, and assign variables which hold the values calculated by this formula, to areas on the object. Then, when the object appears under the light source, its local value will be that of which the color it emits when the wavelengths from the light source reach the object. Then, highlights and shadows would be assigned to the object (I haven't really thought about this part yet, but based on what I have learned in art school, I would use analogous colors and compliments, for a more accurate portrayal.) The atmosphere would actually be the color of the gases which make it up. Clouds would actually take form, and would not just be some background, atmospheric image. Copyright 2008, Nathan Jones, by the way. What I would like to know, is, would this be possible to do with the limitations of today's computing technology? Is it possible to program such an advanced system using OpenGL and C++? I know I could do the C++ part, but does OpenGL have any prohibiting boundaries? Does something like this already exist? I really doubt it, but I never completely throw away the possibility.

Quote:Original post by Yann L

Quote:Original post by anachronistic89
I would create a formula, which calculates the value of the color at any given location.

Well, this equation already exists. It's called the general global illumination equation. In it's complete form (which is not yet 100% complete, because many parts of the equation are not yet fully understood and/or are not computable with todays technology), its complexity is beyond belief.

After applying several very aggressive optimizations, many approximate equation sets were developed over the last 30 or so years: Radiosity, photon mapping, Metropolis LT, and several others. They are still way beyond what current hardware can do in realtime at acceptable quality. Yet, you can use them to precalculate some data to your 3D scene that will later be reused while rendering (see lightmapping, precomputed radiance transfer, etc). These precalculations can take from a few minutes to several weeks depending on the complexity of your scenes. Most current 3D games do that to one extend or another.

Here is some more info to start.

Of course this method is very popular in highend offline rendering, such as for still images, architecture, movies, etc. Most current 3D software include it or can use through plugins (Mental Ray, V-Ray, Maxwell, etc).

Quote:
Copyright 2008, Nathan Jones, by the way.

You legally can't copyright an idea, BTW [wink]

I know that one cannot copyright an idea :P that's just to prevent the lazy people from copying and pasting my post.


Thank you for your reply. I know this will certainly help me along in the process.

Maybe I should study some graphics engines on the code-level.

Are the APIs for the big projects designed specifically for themselves, or do they use OpenGL and so forth?

Yes, radiosity has already proved itself to me as a method worth considering. I will be checking out your demos. I'll be sure to contact you if I have questions. Thanks!


Hmm, has the fact that human vision is trichromatic been used to help simulate color?

Part of my project focuses on the idea of color vision, detail, and all of that. Could it be possible to render based on whether or not the character has pentachromatic/trichromatic/dichromatic color?

Quote:Original post by Yann L

Quote:Original post by anachronistic89
Hmm, has the fact that human vision is trichromatic been used to help simulate color?

Well, look at your screen (which is trichromatic) :)

But yes, of course the human eye is taken into account. Most higher end GI systems use SPDs (spectral power distributions) to calculate the lighting. Generally two types of engines exist: those that calculate everything in linear wavelength space (radiometric engines) and those that use the non-linear weighted visible spectrum (photometric engines). The former ones must convert the radiometric energies to photometric energies when they have completed the calculations. The latter directly operate on photometric units. In order to take the (non-linear) response of the human eye to colours into account (ie. convert from radiometric to photometric data), you need to use the CIE spectral weighting curves. See CIE colour space (or here).

I've just gotten a chance to read all that stuff. Finally on the CIE color link that you've supplied.

From what I read, this is going to make my project all the more fun that I thought it would be :)

It's going to be fun depicting ultra-violet light with the limitation of RGB. I could certainly work with available colors to help do this, because I am sure that bright-magenta colors and purple do not appear in the natural world.

I estimate that it will take a lot more computing to render what I originally wanted.

It will especially take a lot of computing to convert trichromatic into dichromatic, and trichromatic into monochromatic. This is the fun of programming, no? :)

By the way, if there are any projects on here that use dichromatic, monochromatic, and simulated tetrachromatic viewpoints, please link them to here. Also, motion-based vision, blurry vision, and anything like that. In the meantime I will be searching for such things, and working on the project.