POV-Ray

File output code for virtually all file formats performs gamma correction on unclipped color values, which leads to issues when color values happen to be negative for some reason and gamma does not happen to be an integer value such as 1.0 or 2.0. As a consequence, subsequent steps (clipping and converting to integer) apparently produce compiler-dependent results. Compiled with Microsift or Intel compilers, POV-Ray seems to write zero brightness in such cases, while compiled with g++ 4.4 (and possibly other compilers) it seems to write full brightness instead.

(See thread news://news.povray.org:119/4ba819f6@news.povray.org for examples.)

The proper solution should be to apply gamma correction after clipping.

When choosing PPM output with a bit depth other than 8 bits per color channel (e.g. +FP16), POV-Ray messes up the colors (see thread news://news.povray.org:119/4babb48f$1@news.povray.org)

The current Windows version of POV-Ray does not fully support forward slashes in pathnames; specifically, POV-Ray fails to recognize drive letters when followed by a forward slash, e.g. “C:/foo/bar.pov” or “C:/foo\bar.pov”, rejecting such names for e.g. Input_File_Name.

When using cutaway_textures the differenced part traces black. Simple scene file attached.

woodmaps.inc depends on colors.inc, more specifically the definition of the color “Clear” perhaps a #ifndef colors.inc belongs in woodmaps.inc or probably more correctly changing the call of “Clear” to rgbf 1

In pvengine.cpp (file revision 154), lines 4003-4006 are exact duplicates of lines 3999-4002:

3997    case KEYWORD_LOOKUP_MESSAGE :
3998         hh_aklink.pszKeywords = (LPCSTR) lParam ;

3999         if (strncmp (hh_aklink.pszKeywords, "oooo", 4) == 0)
4000           hh_aklink.pszKeywords = ""  ;
4001         if (strncmp (hh_aklink.pszKeywords, "//", 2) == 0)
4002           hh_aklink.pszKeywords = ""  ;

4003         if (strncmp (hh_aklink.pszKeywords, "oooo", 4) == 0)
4004           hh_aklink.pszKeywords = ""  ;
4005         if (strncmp (hh_aklink.pszKeywords, "//", 2) == 0)
4006           hh_aklink.pszKeywords = ""  ;

4007         HtmlHelp (NULL, engineHelpPath, HH_KEYWORD_LOOKUP, (DWORD_PTR) &hh_aklink) ;
4008         return (true) ;

This duplication appears pretty much useless to me - or am I missing something?

The following code is erroneously accepted by POV-Ray (tested with 3.7.0.beta.36):

pigment{
  slope { x }
  checker
}

The result is a checker pattern.

Apparently there is an EXIT statement missing in the slope-pattern parsing code in parstxtr.cpp.

Cone is not on good place when first base point is lower then end cap point.
Example:

cone { <0, 0, 0>, 2, <0, 1, 0>, 1 } - good
cone { <0, 0, 0>, 1, <0, 1, 0>, 2 } - bad

This is on 3.7 beta 35 version.

In POV-Ray 3.6 (including 3.62), checker and cells patterns are off by 0.001 (1e-3) units, as can be demonstrated with this scene:

camera {
  location  <0.0, 0.0, -5.0>
  direction 1.5*z
  right     x*image_width/image_height
  look_at   <0.0, 0.0,  0.0>
}

box { <-1,-1,0>, <0,0,1> pigment { checker color rgb 1 color rgb 0 scale   0.2 translate <-0.5,-0.5,0> } finish { ambient 1 diffuse 0 } }
box { < 1, 1,0>, <0,0,1> pigment { checker color rgb 1 color rgb 0 scale   0.2 translate < 0.5, 0.5,0> } finish { ambient 1 diffuse 0 } }
box { < 1,-1,0>, <0,0,1> pigment { checker color rgb 1 color rgb 0 scale 200.0 translate < 0.5,-0.5,0> } finish { ambient 1 diffuse 0 } }
box { <-1, 1,0>, <0,0,1> pigment { checker color rgb 1 color rgb 0 scale 200.0 translate <-0.5, 0.5,0> } finish { ambient 1 diffuse 0 } }

The same can be demonstrated for the cells pattern.

POV-Ray 3.7 beta 34 is “clean”.

Bounding box computation for CSG intersection appears to be broken when one member is an arbitrarily transformed plane.

// +W640 +H480 +MB1

#include "transforms.inc"

camera {
  location  <-0.2, 0.5, -4.0>
  direction 1.5*z
  right     x*image_width/image_height
  look_at   <0.0, 0.0,  0.0>
}

sky_sphere {
  pigment {
    gradient y
    color_map {
      [0.0 rgb <0.6,0.7,1.0>]
      [0.7 rgb <0.0,0.1,0.8>]
    }
  }
}

light_source {
  <0, 0, 0>            // light's position (translated below)
  color rgb <1, 1, 1>  // light's color
  translate <-30, 30, -30>
}

plane {
  y, -1
  pigment { color rgb <0.7,0.5,0.3> }
}

intersection {
  sphere {
    0.0, 1 }
  plane { -x, 0 transform { Shear_Trans(x,y+x*0.3,z) } }
  texture {
    pigment {
      radial
      frequency 8
      color_map {
        [0.00 color rgb <1.0,0.4,0.2> ]
        [0.33 color rgb <0.2,0.4,1.0> ]
        [0.66 color rgb <0.4,1.0,0.2> ]
        [1.00 color rgb <1.0,0.4,0.2> ]
      }
    }
    finish{
      specular 0.6
    }
  }
  rotate -y*5
}

The following scene, showing an almost cylindrical cone floating above a plane, renders fine in POV 3.6.2, but is obviously broken in 3.7.0.beta.34:

camera {
  right     x
  up        y*image_height/image_width
  location  <80,50,40>
  look_at   <0,0,0>
}

light_source { <500,500,500> color rgb 1 }

cone {
  <0,0,30>, 11.303000, <0,0,-30>, 11.302999
  texture { pigment { color rgb 1 } }
}

plane { y, -20 texture { pigment { color rgb 0.3 } } }

The error occurs even with the -MB option, indicating that the problem has nothing to do with bounding, but is in the cone intersection testing code.

(This happens as of beta 34)

The following scene will cause POV-Ray to allocate memory until all available memory is used, resulting in an Out of Memory error message:

#declare n1 = normal
{
    crackle .5
    scale 0.001
    accuracy 0.0001
}

#declare n2 = normal
{
    bumps 0
}

camera
{
    location <0, 0.2, -1>
    look_at <0.4, 0.3, 1>

    focal_point <0.4, 0.3-.0, 1>
    blur_samples 25
    confidence .9
    variance 0
    aperture .05
}

light_source
{
    <-10, 10,-5>, rgb 1.5
    area_light x*2,y*2,7,7 orient adaptive 2
}

sphere{ <0, 0, 0>, 0.5 pigment {color rgbf <0.85,1,.95,1>}

    interior
    {
        ior 1.5
        fade_color rgb <0.0, 0.5, 0.0>
        fade_power 2
        fade_distance 10.5
        dispersion 1.1
        dispersion_samples 100
    }

    normal {

        checker normal{n2} normal{n1}
        scale 0.1
        warp { spherical }

    }

    translate z*1
} 

The attached TIFF file was created with IC using compression. When used in an image_map, POV-Ray 3.7.0.beta.34 on Windows XP x64 renders the image all transparent, while POV-Ray 3.6.2 renders the file fine. The same effect can be seen with LZW-compressed TIFF files created with Adobe Photoshop 6.0.

Uncompressed TIFF files created with either IC or Photoshop render fine in both versions of POV-Ray.

Stepping through the code of POV-Ray 3.7.0 shows that the same code path is taken regardless of compression, but the libtiff library returns different alpha channel values, indicating a problem in that library. POV-Ray 3.7 still uses libtiff 3.6.1, whereas the POV-Ray 3.6 branch has been updated to libtiff 3.8.2, which according to the change history includes a few alpha-related changes.

Source code inspection during examination of issues with the scene published at http://povray.sitewww.ch/?p=177 show the following issues with current (beta.34) implementation of dispersion in POV-Ray 3.7:

• The same adjustment to the IOR that is applied at the very first dispersion interface is erroneously applied to all subsequent interfaces.

• As an exception, dispersion adjustment is erroneously not applied to any interface defined by the surface of a non-dispersing object embedded into a dispersing object.

While this still allows to use dispersion for artistic effect, it is neither physically realistic, nor does it match 3.6 behavior.

Reported by cshake + pov @ gmail . com in p.beta-test, 14th december 2009

I wrote a simple script to convert fractint color maps to povray color_maps so I could use ApoMap to make nice fractal colors for pov, but I ran into
“Parse Error: Blend_Map too long.” The map has entries from 0/255 up to 255/255 (inclusive). I looked up the documentation which says that color_maps can have from 2 to 256 entries, and this is exactly 256 entries.
I’m posting this in beta-test because I assume that the documentation is correct for v3.6, and that a previous version can handle 256 entries.

Windows 7, Home Premium 64bit
In Options/Editor Window/Editor Preferences/Language Tabs
saving a tab size of 4 does not work - on restart it reverts to the default of 8

In Options/Editor Window/Editor Preferences/Misc
saving a Line numbering style of Decimal and a Start number of 1, does not work, on restart the defaults are restored.

I cannot edit any pages on wiki.povray.org, even after confirming my e-mail address.

This means that I cannot add any documentation, help improve the documentation, fix errors or help in any other way.

If you want contributions to the documentation, you should let users edit pages.

After a recent update on the POV-Wiki the GuMax skin doesn’t recognize MediaWiki:Common.css entries.

Add a way to get and set font metrics.

Attached an image that shows what I’m talking about.

Thanks!!

Improve native support for 2D primitives. Ideally a 1:1 mapping of SVG primitives/shapes. They go a long way to making diagrams look a lot better. Having to create image maps based on externally created bitmaps slows the workflow down a lot!

Add metatags to output images identifying the file as having been created using POV-Ray.

Scenes starting with the incorrect syntax

version 3.7;

do not raise an error, instead they render a black screen with an empty scene warning.
#version should fail with an error when the # is missing.

At the moment in the Poly Object the maximum power is 15. The mathematics for converting the three parametric equations for x, y and z into a formula for the Poly Object require that the equations are squared several times given max-powers of 4, 8 and even 16. I’ve one eqaution that needs power 16. At the moment this is just one power short. Please raise this to 16. That’s all I ask for.

For some particularly “heavy” SDL scripts, it might be desirable to override (or complement) the standard “Parsing 47110815K tokens” progress information with some more helpful custom info, e.g. “Planting trees... (37%)”, or “Generating terrain mesh row 47 of 500”.

Many people clearly miss a simple for-loop construct in povray. It is indeed true that probably at least 99% of #while loops out there have the form of a simple for-loop. It’s much rarer to have to use more exotic forms of looping supported by the #while mechanism. Thus it would make sense if a #for construct would be added which would make writing such loops much easier and convenient.

The only remaining question would be the syntax.

IMO the for-loop construct should implicitly declare a local variable of a specified name, automatically increment it during the loop, and then undefine it after the loop ends. It could perhaps be something along the lines of:

#for(<identifier name>, <initial value>, <final value> [, <step>])
  <loop body>
#end

Example:

#for(Counter, 1, 10) // 'Counter' gets values 1, 2, 3, ..., 10
  #debug concat(str(Counter, 0, 0), "\n")
#end
#for(Counter, 1, 10, 3) // 'Counter' gets values 1, 4, 7, 10
  #debug concat(str(Counter, 0, 0), "\n")
#end

I think this syntax ought to be relatively easy to implement (compared to more “traditional” syntaxes, such as something like “for Counter = 1 to 10” or the C syntax, which would be a lot more complicated).

Of course this raises a couple of questions:

1) What happens if ‘Counter’ was already declared as an identifier? One of three possibilities comes to mind:

• The ‘Counter’ in the for-loop replaces the previous identifier, as a regular #local command would.

• The ‘Counter’ in the for-loop hides the identifier for the duration of the loop, and unhides it afterwards.

• A syntax error is given (ie. the identifier name must be unused).

2) Should the user be able to modify the counter variable from inside the body of the loop? Something like this comes to mind as viable:

// Prints the values 1, 2, 3, 9 and 10
#for(Counter, 1, 10)
  #debug concat(str(Counter, 0, 0), "\n")
  #if(Counter = 3) #local Counter = 8; #end
#end

Alternatively the counter variable could be read-only.

Additionally, it could be nice if #break could be used to immediately jump out of the current loop (either #while or #for).

Linux beta 32, 64bits, compiled from sources.

povray -w800 -h600 +a0.3 +kfi1 +kff78
-L/usr/local/share/povray-3.7/scenes/incdemo
-Ii_internal.pov +WT5 +R4 +AM1 +MB1

Important issue: +WT5 +MB1

Seems Fine for +WT1 +MB1
Also fine for +WT5 +MB9

The intersection with the containing box displays some two-shades of grey
random checkered patterns.
Size of square looks like size of renderering thread. Position too.

Impacted frames (of 78):
01, 02, 03, 30, 48, 74, 76.

I’ve been trying to upgrade povray 3.6.1 to 3.7-beta-32. I’ve configured with no additional arguments, and the configure dies with:

checking whether to build the boost thread library from sources... no
checking for boostlib >= 1.35... yes
checking whether the Boost::Thread library is available... yes
checking for exit in -lboost_thread... no
checking for exit in -lboost_thread-boost_thread... no
configure: error: Could not link against boost_thread-boost_thread !

I figured that the problem was with my boost installation (1.35) and upgraded boost to 1.39; the problem remains. I tried to see if exit was defined in libboost_thread and/or libboost_thread-boost_thread and it isn’t. Just to be sure that my currrent setup works for the released version, I rebuilt/reninstalled 3.6.1, which went without problem.

I’m on a slackware-12.2 box, using gcc-4.4.0.

The following (bogus) SDL code causes POV-Ray 3.7 beta to crash hard with an access violation:

#include "fubar.inc"
Bar(42)
#macro FooBar() #end

//fubar.inc
#macro Foo(Fnord) #end
#macro Bar(Ignord) Foo(23 #end

Beta 32 is failing to render a mesh2 smoothly on 64-bit XP - output shows flat triangles rather than smoothed triangles.
Issue is not present in 32-bit build.

Reported in http://news.povray.org/49e51489%241%40news.povray.org. Demo image rendered using standard chessmesh scene.

The version 3.6 documentation needs to be updated to suit the changes for version 3.7.

Input image files may have been created with gamma pre-correction for some specific target gamma, which may vary from image to image. Some file formats like PNG or HDR support embedding gamma pre-correction information in the image file, but this information may be missing or faulty, and some formats don’t support it at all. Additionally, it may be desirable to tamper with an input image’s gamma for artistic reasons.

Therefore, I suggest adding a means to explicitly specify input images’ originally intended target gamma on a per-image basis, like:

image_map { jpeg "MyImage.jpg" assumed_gamma 1.8 }

Files of exactly 4k length can cause a full crash exception when opened.

Overlapping partially transparent objects can result in speckled shadows.
Rays shouldn’t leak through the coincident areas, they should return one
of the two textures. This was correct in 3.6.

#declare testmat = material { texture {
      pigment {color <1,0,0> transmit 0.5}
}};

camera { location  <1.0, 2.0, -4.0>
   direction 1.5*z
   right     x*image_width/image_height
   look_at   <1.0, -0.2,  0.0>
   angle 30 }

light_source {<-10, 10, -5> color rgb <1, 1, 1>}

plane {y,-1 pigment{rgb <1,1,1>}}

union {
   sphere {<0.0,0,0>,0.5 material{testmat}}
   sphere {<0.1,0,0>,0.5 material{testmat}}
   sphere {<0.2,0,0>,0.5 material{testmat}}
   sphere {<0.3,0,0>,0.5 material{testmat}}
   sphere {<0.4,0,0>,0.5 material{testmat}}
   sphere {<0.5,0,0>,0.5 material{testmat}}
}

Using trace or inside with a julia fractal causes a crash.

#declare Test = julia_fractal {
  <-0.083,0.0,-0.83,-0.025>
  quaternion
  cube 
  max_iteration 8
  precision 20
};
#declare Norm = <0,0,0>;
#declare Hit = trace(Test,<0,0,-10>,z,Norm);
#declare Center = inside(Test,<0,0,0>);