Please see the attached code. Take special note on line 62. If you
remove it or comment it, the parser gives an error. I have no idea
why, but it seems like a parser bug.


Peter Popov
ICQ: 15002700

Post a reply to this message

Attachments:
Download 'glass.pov.txt' (5 KB)

Darn.  I thought I fixed that.  That's what I get for playing with the parser
without knowing what I'm doing.  I'll work on it and get back to you soon.

-Nathan

Peter Popov wrote:
> 
> Please see the attached code. Take special note on line 62. If you
> remove it or comment it, the parser gives an error. I have no idea
> why, but it seems like a parser bug.
> 
> Peter Popov
> ICQ: 15002700

Post a reply to this message

Ok.  I think I fixed it now.  I'm going to wait to upload the new version,
though.  If other people run into problems, I'll upload this fix, but I
want to check it out more first, since I'm not sure exactly how this part
of the parser works yet.

-Nathan

Peter Popov wrote:
> 
> Please see the attached code. Take special note on line 62. If you
> remove it or comment it, the parser gives an error. I have no idea
> why, but it seems like a parser bug.
> 
> Peter Popov
> ICQ: 15002700

Post a reply to this message

In article <37650b3a.4662718@news.povray.org> , pet### [at] usanet (Peter
Popov) wrote:

> Please see the attached code. Take special note on line 62. If you
> remove it or comment it, the parser gives an error. I have no idea
> why, but it seems like a parser bug.
>
>
> Peter Popov
> ICQ: 15002700
>

>#declare T_Wood34 =
>texture { T_Wood32 }
>texture  {
>    pigment {
>        onion
>        turbulence 0.2125
>        colour_map {
>            [0.225 colour rgbt <1.000000, 0.53333, 0.11767, 0.4875>]
>            [0.350 colour rgbt <0.662750, 0.28617, 0.00001, 0.7250>]
>            [0.500 colour rgbt <1.000100, 0.53333, 0.11765, 0.5745>]
>            [0.625 colour rgbt <0.662775, 0.28627, 0.00005, 0.6875>]
>            [0.750 colour rgbt <1.000200, 0.53333, 0.11755, 0.5275>]
>            [0.875 colour rgbt <0.662755, 0.28629, 0.00001, 0.3795>]
>            [1.000 colour rgbt <1.000000, 0.53333, 0.11665, 0.6165>]
>        }
>        scale <0.225, 0.20, 1.15>
>    }
>  }


Interesting, I didn't know that this was (ever) supposed to work at all (I
didn't miss the note of that exception the POV-Ray Docs, did I?). I
would say the parser is right...


    Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: Tho### [at] csicom

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

That's how you do layered textures.  And this parser keeps looking harder
and harder to fix.  :-(  ...and it looked so easy at first.

-Nathan

Thorsten Froehlich wrote:
> Interesting, I didn't know that this was (ever) supposed to work at all (I
> didn't miss the note of that exception the POV-Ray Docs, did I?). I
> would say the parser is right...
> 
>     Thorsten
> 
> ____________________________________________________
> Thorsten Froehlich, Duisburg, Germany
> e-mail: Tho### [at] csicom
> 
> Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

In article <3766F4D6.DFC19439@Kopp.com> , Nathan Kopp <Nat### [at] Koppcom>  
wrote:

> That's how you do layered textures.  And this parser keeps looking harder
> and harder to fix.  :-(  ...and it looked so easy at first.

Yes, layered textures _inside_ object declarations, but if I read this right

#declare T_Wood34 =
texture { T_Wood32 }
texture  { ... }

should (or will) only declare

#declare T_Wood34 =
texture { T_Wood32 }

and I suppose that the parser complains about the second texture { ... } if
the #if .. #end isn't there.  I would suggest to declare each of the
textures and then use each of them in the object which still gives a layered
texture.


    Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: Tho### [at] csicom

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

Thorsten Froehlich wrote:
> 
> In article <3766F4D6.DFC19439@Kopp.com> , Nathan Kopp <Nat### [at] Koppcom>
> wrote:
> 
> > That's how you do layered textures.  And this parser keeps looking harder
> > and harder to fix.  :-(  ...and it looked so easy at first.
> 
> Yes, layered textures _inside_ object declarations, but if I read this right
> 
> #declare T_Wood34 =
> texture { T_Wood32 }
> texture  { ... }
> 
> should (or will) only declare
> 
> #declare T_Wood34 =
> texture { T_Wood32 }
> 
> and I suppose that the parser complains about the second texture { ... } if
> the #if .. #end isn't there.  I would suggest to declare each of the
> textures and then use each of them in the object which still gives a layered
> texture.
> 
>     Thorsten
> 
> ____________________________________________________
> Thorsten Froehlich, Duisburg, Germany
> e-mail: Tho### [at] csicom
> 
> Visit POV-Ray on the web: http://mac.povray.org


  Dating back at least as far as Pov v2.2 it has been valid to declare
textures as previously illustrated i.e.

#declare T1 = 
texture { ... }
texture { ... }

object { thing texture { T1 }}

  I have designed and used so many layered textures this way I can verify it's
legitimacy.

-- 
Ken Tyler

mailto://tylereng@pacbell.net

Post a reply to this message

On Wed, 16 Jun 1999 16:35:20 +0200, Thorsten Froehlich wrote:
>In article <3766F4D6.DFC19439@Kopp.com> , Nathan Kopp <Nat### [at] Koppcom>  
>wrote:
>
>> That's how you do layered textures.  And this parser keeps looking harder
>> and harder to fix.  :-(  ...and it looked so easy at first.
>
>Yes, layered textures _inside_ object declarations, but if I read this right
>
>#declare T_Wood34 =
>texture { T_Wood32 }
>texture  { ... }
>
>should (or will) only declare
>
>#declare T_Wood34 =
>texture { T_Wood32 }

From the documentation, the section on layered textures:

---------------
    Layered textures may be declared. For example

    #declare Layered_Examp = 
      texture {T1}
      texture {T2}
      texture {T3}
---------------

In fact, there are places you can't use a layered texture directly
but you may use a declared one.  From the same page in the docs:

---------------
    If you wish to use a layered texture in a block pattern, such as 
    checker, hexagon, or brick, or in a material_map, you must declare 
    it first and then reference it inside a single texture statement.
---------------

And here's the code from the parser, from parse.c in the function 
Parse_RValue.  The interior EXPECT loop takes care of any remaining 
texture definitions after the first one, linking them to form a 
layered texture.  

---------------
    CASE (TEXTURE_TOKEN)
      Parse_Begin ();
      Local_Texture = Parse_Texture ();
      Parse_End ();
      Temp_Texture=NULL;
      Link_Textures(&Temp_Texture, Local_Texture);
      Ok_To_Declare = FALSE;
      EXPECT
	CASE (TEXTURE_TOKEN)
	  Parse_Begin ();
	  Local_Texture = Parse_Texture ();
	  Parse_End ();
	  Link_Textures(&Temp_Texture, Local_Texture);
	END_CASE

	OTHERWISE
	  UNGET
	  EXIT
	END_CASE
      END_EXPECT

      *NumberPtr    = TEXTURE_ID_TOKEN;
      Test_Redefine(Previous,NumberPtr,*DataPtr);
      *DataPtr      = (void *)Temp_Texture;
      Ok_To_Declare = TRUE;
      EXIT
    END_CASE
---------------

Post a reply to this message

In article <3767bb49@news.povray.org> , par### [at] fwicom (Ron Parker) wrote:

> From the documentation, the section on layered textures:
>
> ---------------
>     Layered textures may be declared. For example
>
>     #declare Layered_Examp =
>       texture {T1}
>       texture {T2}
>       texture {T3}
> ---------------
>
> In fact, there are places you can't use a layered texture directly
> but you may use a declared one.  From the same page in the docs:
>
> ---------------
>     If you wish to use a layered texture in a block pattern, such as
>     checker, hexagon, or brick, or in a material_map, you must declare
>     it first and then reference it inside a single texture statement.
> ---------------

Aha, so I really missed that :-)   Well, I don't use layered textures very
often...

> And here's the code from the parser, from parse.c in the function
> Parse_RValue.  The interior EXPECT loop takes care of any remaining
> texture definitions after the first one, linking them to form a
> layered texture.

Makes sense.  Thank you for the clarification.


      Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: Tho### [at] csicom

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

I'm uploading the new patch now.  Hopefully this one will really fix the
bugs.  I put back the original #declare code, so all #declares should
have no problem.  No guarantees with my new parser stuff (the $ and %
shortcuts) though.

-Nathan

Peter Popov wrote:
> 
> Please see the attached code. Take special note on line 62. If you
> remove it or comment it, the parser gives an error. I have no idea
> why, but it seems like a parser bug.

Post a reply to this message