"Kenneth" <kdw### [at] gmailcom> wrote:
> I've been working on a 'city building generator'-- part of my earlier post re:
> 'green gas cloud.' I put aside the media cloud for now...
>
> Currently, the buildings are just randomly placed. I've made no attempt to put
> them into a 'street grid' yet. (Perhaps real-world real-estate prices will be so
> high in the future that buildings will NEED to be overlapped by economic
> necessity, ha!)
>
> The buildings' facades and windows are from photos I got off the 'net-- then
> re-worked in Photoshop to be small 'tiles' that can be repeated. Then I took the
> same tiles and made 'reflection hold-out mattes', for the windows themselves.
> (That took a lot of manual labor.) The two different images are combined in the
> many textures' image_pattern {...} blocks, so that reflections only show up in
> the glass windows. The 'image_pattern' feature is great for creating 'texture
> masks'.
>
> The photo tiles (I've used only eleven so far, randomly repeated) are all in
> different shapes and resolutions. I *could* have re-made them to be the same rez
> and shape (more or less) in PS-- but it was more fun to write SDL code to take
> care of that, using 3.7xx's new max_extent feature for finding the X/Y rez of an
> image.
>
> Applying image_maps to all four sides of a box shape would seem to be a simple
> procedure (and it is, if that's all that's required.) But I decided to 'enclose'
> the image tiles in POV-Ray's 'boxed' pattern-- to create a thin 'concrete
> outline' around the (four) faces of each building, with a larger one at the top.
> I didn't want the buildings' window images to go all the way to the side edges;
> that would look odd and unrealistic. This extra step took most of the coding
> effort-- making sure that it worked at all building scales, while also keeping
> all the buildings' windows at the SAME relative scale. (Obviously, each floor of
> each building should be the same height!)
>
> I made an interesting discovery with the windows: The raw photos already showed
> natural reflections there-- which didn't look correct when applying 'extra'
> reflection in POV-Ray. In real life, windows in buildings are very dark (when
> NOT reflecting anything) because the room interiors behind them are dark,
> *compared to* the buildings' bright sunlit exteriors. SO, I had to darken the
> window areas in all the photos to remove that reflected look, then add it back
> in in POV-ray.
>
> Instead of using real photos for this, it would be interesting
> to try and create some sort of 'window/facade' generator, using procedural
> textures in POV-Ray instead. As a guess, it might be done with a combination of
> the 'boxed' pattern, the 'cells' pattern, and warp{repeat...} in some kind of
> combination, along with random variations of all the elements. (BTW, I haven't
> yet looked at any of the building generator .inc files or macros that are
> available; I first wanted to see how far I could go, before I needed help!)
>
> Still to do: Figuring out a way for each building's width and height to be
> strict multiples of its image_map tile size-- so that a building's edge doesn't
> end in the middle of a window! (Which is currently what happens, as the
> buildings are just randomly sized.) I may have to rewrite a good chunk of my
> code to do that :-/
>
> Another way to make a building would be with *heightfields* for the faces, to
> show their natural 3-D appearance (balconies, recessed windows, etc.) I'm
> working on that too-- I've already made HF image_maps from most of the image
> tiles-- but it's a tedious Photoshop procedure (and involves rewriting my
> code yet again.)

I really like it, and I will be really interested to see what you come up with
using heightfields.

I have tried to do this (on and off) but was never satisfied with the result.
The only efforts I did like were ones where the results were viewed from a
distance (at night, in fog, in outline, with focal blur and the camera pointing
in the opposite direction).

I have tried the cell pattern with mild turbulence (<= 0.1) and it can be made
to work at a distance. Up close I have only ever used it for flagstones. I have
also tried a variety of brick textures, but again was only ever satisfied with
them at a distance.

Cheers,

Simon.

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