Widening Our 3D Graphics Capabilities under FOSS

Just so that I can say that my 3D Graphics / Model Editing capabilities are not strictly limited to “Blender”, I have just installed the following Model Editors on the Linux computer I name ‘Klystron’, that are not available through my package-manager:

I felt that it might help others for me to note the URLs above, since correct and useful URLs can be hard to find.

In addition, I installed the following Ray-Tracing Software-Rendering Engines, which do not come with their own Model Editors:

Finally, the following was always available through my package manager:

  • Blender
  • K-3D
  • MeshLab
  • Wings3D

 

  • PovRay

 

In order to get ‘Ayam’ to run properly – i.e., be able to load its plugins and therefore load ‘Aqsis’ shaders, I needed to create a number of symlinks like so:

( Last Updated on 08/19/2017, 19h55 )

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The role Materials play in CGI

When content-designers work with their favorite model editors or scene editors, in 3D, towards providing either a 3D game or another type of 3D application, they will often not map their 3D models directly to texture images. Instead, they will often connect each model to one Material, and the Material will then base its behavior on zero or more texture images. And a friend of mine has asked, what this describes.

Effectively, these Materials replace what a programmed shader would do, to define the surface properties of the simulated, 3D model. They tend to have a greater role in CPU rendering / ray tracing than they do with raster-based / DirectX or OpenGL -based graphics, but high-level editors may also be able to apply Materials to the hardware-rendered graphics, IF they can provide some type of predefined shader, that implements what the Material is supposed to implement.

A Material will often state such parameters as Gloss, Specular, Metallicity, etc.. When a camera-reflection-vector is computed, this reflection vector will land in some 3D direction relative to the defined light sources. Hence, a dot-product can be computed between it and the direction of the light source. Gloss represents the power to which this dot-product needs to be raised, resulting in specular highlights that become narrower. Often Gloss must be compensated for the fact that the integral of a power-function, is less than (1.0) times a higher power-function, and that therefore, the average brightness of a surface with gloss would seem to decrease…

But, if a content-designer enrolls a programmed shader, especially a Fragment Shader, than this shader replaces everything that a Material would otherwise have provided. It is often less-practical, though not impossible, to implement a programmed shader in software-rendered contexts, where mainly for this reason, the use of Materials still prevails.

Also, the notion often occurs to people, however unproven, that Materials will only provide basic shading options, such as ‘DOT3 Bump-Mapping‘, so that programmed shaders need to be used if more-sophisticated shading options are required, such as Tangent-Mapping. Yet, as I just wrote, every blend-mode a Material offers, is being defined by some sort of predefined shader – i.e. by a pre-programmed algorithm.

OGRE is an open-source rendering system, which requires that content-designers assign Materials to their models, even though hardware-rendering is being used, and then these Materials cause shaders to be loaded. Hence, if an OGRE content-designer wants to code his own shader, he must first also define his own Material, which will then load his custom shader.

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This Time, some Real Computer Achievement

Contrarily to how easy it was to set up my Joystick the other day, yesterday and today I have been busy with the laptop I name ‘Klystron’ that actually required some computer-skills on my part.

It was a subject of mine for a long time, how 3D Game Design works, and in particular, how the raster-based DirectX or OpenGL rendering works. To study that subject in my private time, I have always maintained a set of programs, that would in theory enable me to create a game.

In practice, creating any game decent enough to play, requires oodles of time and work. But I always felt that the software-tools involved should belong to my collection, even if I do not really put them to thorough use.

One software tools I have been pursuing, is the graphics rendering engine called “OGRE“. For several years I have been trying to custom-compile OGRE 1.10, just because that version offers better support for OpenGL 3, which should give game authors access to Geometry Shaders. But as it happens, I have ‘Mesa‘ drivers installed on that laptop, that do claim to create support for OpenGL 3, but that oddly, do not go so far as to offer Geometry Shaders. This is not a fault of the OGRE development team.

Also, there are reasons for which I do not simply ditch the Mesa drivers for ‘fglrx‘, the latter of which would give me OpenGL 4: I find it important enough, that the Mesa drivers allow hardware-acceleration of regular, high-def, 2D video streams. I would not want a real video stream / movie to become a burden to my CPU, and the fglrx do not GPU-accelerate that. So I stick with the Mesa drivers.

But then there was only one good way to get my OGRE install stable. I had to switch the Mercurial version of it I was subscribing to, down to OGRE 1.9, which is highly stable. The only issue with that remains, that OGRE 1.10 would have been my only game engine, which would have ever offered me full OpenGL 3. Which was just not stable on that box.

Now that the OGRE version on ‘Klystron’ is a sensible 1.9, that also means the engine has no extreme advantage over other game engines I possess. They all tend to be of the vanilla variety, that offer OpenGL 2 / DirectX 9c… – GL 3 would be equivalent to Dx 10, and GL equivalent to Dx 11.

Speaking of vanilla, I also installed the latest snapshot of Crystal Space on ‘Klystron': Version 2.1 ! I am amazed at how much better this latest build of Crystal Space seems, in terms of being stable when compiled, than earlier builds of it were.

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