Addressing the "transparency degree setting means" issue: I believe prior art is very clearly shown by Blender's Mist feature, which uses this technique and is documented here.
That page is marked as modified in 2011, but the history goes back earlier; the use of adjusting transparency based on the distance is first mentioned in this version of the page from ...
Prior art for this would appear to be OpenGL. Any version of OpenGL. Yes, even OpenGL 1.0, published in 1994. Let's take these in order:
object placement means for placing a predetermined object in the virtual space;
Yes, OpenGL can be used to do that.
transparency degree setting means for, in accordance with a distance specified between (1) ...
This shows how to calculate fog/mist with distance, such that objects merge with the background the further away you go:
“Visual simulation of atmospheric haze”, P J Willis, Computer Graphics Forum, 6, 1, Jan 1987, pp 35-43.
The Source engine has support for fading "props", 3d models in levels, based on the distance. See the BaseFadeProp section of https://developer.valvesoftware.com/wiki/Prop_static for an example.
It has publicly released support for stereographic rendering since earlier this year. This by the use of the Oculus devkit. The free to play game "Team Fortress 2" ...
Magic Carpet by Bullfrog used the same technique in 1994 to hide the limited rendering-powers of Pentium pcs... It was a cool way to make the more distant scenery disappear.
I found the following review from 1994:
The texture-mapped polygons are expertly depth cued and shade off into a beautiful mist effect in the near distance – this not only softens ...
Minecraft added its initial test support on 2009-08-13 for anaglyph 3D (anaglyph 3D is a form of stereoscopic 3D, as per the claims), and the fog that fades objects out as their distance from the camera increases predates at least 2009-05-20, since an option to modify the distance the fog is at was added on that date.
This YouTube video of Minecraft, dated ...
The technique of fading an object based on distance has been used in videogames and 3d applications for decades. See the "LOD Blending" section of the Wikipedia article on "Popping (computer graphics)":
Isn't this how a lot of games do LOD swapping, to cross-fade between a complex object and a simpler mesh (or texture billboard) as it got further from the camera? The earliest case I can clearly remember is the foliage in DICE's "Battlefield 1942" (published in 2002), but I'm sure there must be others.