POV-Ray : Newsgroups : povray.animations : Calling an Image Map with an array identifier that stores the image file na= : Re: Calling an Image Map with an array identifier that stores the image fil= Server Time
19 Sep 2021 19:21:09 EDT (-0400)
  Re: Calling an Image Map with an array identifier that stores the image fil=  
From: Kenneth
Date: 2 Dec 2018 20:10:00
Message: <web.5c04806ab4bd0d7acd98345b0@news.povray.org>
Stephen <mca### [at] aolcom> wrote:
> On 02/12/2018 16:26, Kenneth wrote:
> >
> > My own particular set-up would be...
> >
> > box{0, <1,1,0>
> > pigment{
> > image_map{png concat("my_image",str(frame_number,-4,0),".png")
>
> I'll just point out, again. That the BITMAP_TYPE should not be included
> in the concat function. When I tried that earlier, Pov threw a wobbly
> and complained that the first letter of the file path was an undeclared
> variable "C".

Yes-- BITMAP_TYPE being the *first* .png in the code line. I ran into the same
problem years ago, even without the use of a C: library path as in your example.
That 'png' is a keyword (or sort of like one), and I could never figure out a
way to get a string construction to 'create' a POV-Ray keyword. I assume it
can't be done-- but it would be an interesting feature to add in the future (if
possible!)  ;-)

> Also #debug would not output the result of:
> image_map{concat("png  ","my_image",str(frame_number,-4,0),".png")
> That made me feel that I was losing my marbles for a while.
>

This works for me...
#debug concat ("\n","my_image",str(frame_number,-4,0),".png","\n")

I think the "\n" line feeds are necessary to even see the #debugged message;
there is an older post about how the absence of them causes the message pane to
ignore #debug...sometimes ;-) The details were somewhat complicated, IIRC.

When using the C: path method instead, I came across some info in the built-in
documentation at   3.3.1.9 Strings   about backslashes, that might be of
interest...
---
Windows users need to be especially wary about this as the backslash is also the
windows path separator. For example, the following code does not produce the
intended result:
#declare DisplayFont = "c:\windows\fonts\lucon.ttf"
  text { ttf DisplayFont "Hello", 2,0 translate y*1.50 }

New users might expect this to create a text object using the font
c:\windows\fonts\lucon.ttf. Instead, it will give an error message saying that
it cannot find the font file c:windowsontslucon.ttf.

The correct form of the above code is as follows:
#declare DisplayFont = "c:\\windows\\fonts\\lucon.ttf"
  text { ttf DisplayFont "Hello", 2,0 translate y*1.50 }

However, as POV-Ray for Windows also supports forward slashes as path separator,
it is recommended to use the following form: #declare DisplayFont =
"c:/windows/fonts/lucon.ttf"

Note: Up to (and including) version 3.7.0, contrary to the documentation (and on
all platforms) backslashes lost their special meaning where a file name is
expected, except when preceding a double quote. For backward compatibility, this
behaviour is still retained for scenes specifying a #version of 3.70 or lower,
but a warning will be issued.

---

The only remaining mystery for me is whether or not a line feed "\n" should use
a forward slash as well; I don't see that distinction in the docs.


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