POV-Ray

The following scene reders differently with POV-Ray 3.7.0.RC3 than with POV-Ray 3.6.2:

camera
{
    right x*image_width/image_height
    location  <0, 0, -5>
    look_at   <0, 0, 0>
}

light_source
{
    <0,0,0>
    color rgb 1
    looks_like
    {
        box {
            <-1,-1,-0.1>, <1,1,0.1>
            pigment { wood }
            finish { ambient 5.0 diffuse 0 specular 0 phong 0 reflection 0 }
            scale 0.5
        }
    }
    translate <1,0,0>
}

plane
{
    <0, 1, 0>, -1
    texture
    {
        pigment { color rgb <0.5, 0.5, 0.55> }
        finish { specular 1.0 }
    }
}

See attachments for the output. As can be seen, POV-Ray 3.7 does translate the shape of the looks_like object along with the light source, but fails to translate the textures.

There is a long animation to render.

computer 1 should render 0..799
computer 2 should render 800..1599

And after this, You have a bad surprise with the filenames.

animation799.png
animation0800.png

There should be a seting how many digits a file name in an animation should have.

This avoids, that there are series of pictures with 3 and other with 4 digit filenames.

BTW: All the experiences for this feature requests had been made during producing
http://roland.pege.org/2011-gusi-peace-prize/calculation-error.htm

parser fails to report when an illegal map_type is used. For example map_type 10 and map_type 100 doesn’t produce an error

As posted in povray.beta-test 2012-01-14 with the same subject.

OS Win7 32 bit

The following code fails with the following message:
Picture index out of range.
Picture index out of range.
Fatal error in renderer: Uncategorized error.
Render failed

The texture scale is relevant.

It does not fail in Pov 3.62
The image map can be downloaded from:
http://www.mmedia.is/~bjj/data/s_rings/sat_ring_color.png

(Attached)

#version 3.7;

global_settings {
adc_bailout 0.0039
ambient_light rgb <1.000,1.000,1.000>
assumed_gamma 1.00
irid_wavelength rgb <0.250,0.180,0.140>
max_trace_level 5
number_of_waves 10
noise_generator 3
charset ascii
}

background { colour rgb <0.000,0.000,0.000> }

#declare Ring_Texture1 =
texture {
uv_mapping
pigment {

image_map{
 png "sat_ring_color.png"
 interpolate 2
 map_type 0
}
rotate    <90.000,90.000,0.000>

}

finish {

ambient     rgb <0.100,0.100,0.100>
brilliance  1.000
crand       0.000
diffuse     0.600
metallic    0.000
phong       0.000
phong_size  40.000
specular    0.000
roughness   0.050

}

}

#declare Camera0 =
camera {
perspective
location <3843.816,38.892,-2660.667>
up y
right 1.333*x
angle 33.000
sky ←0.004,1.000,0.002>
look_at < 0.449, 18.943, 0.102 >
} end Camera0 disc { Disc0
0,y,4.400000,2.500000
texture{ Ring_Texture1 }

  scale     <750.000000,750.000000,750.000000>      // Fails 32 bit

scale <800.000000,800.000000,800.000000> Fails 64 bit
scale <600.000000,600.000000,600.000000> does not fail
rotate <0.000000,0.000000,-20.000000>
translate ←3500.000000,900.000000,900.000000>
} end Disc0 camera{ Camera0 } ///

The +GD flag gives me an “Invalid parameter” error, whether on the command line or in a .ini file.

Debug_File= still works.

I reported this in povray.beta-test, but did not receive a response.

The problem occurs in both Windows 7 and in Linux.

~scenes/advanced/optics.pov not rendering correctly. See the post in povray.beta-test “Photons not working as expected” for additional information.

Suggestion:

In file screen.inc, have macro Screen_Object() set no_radiosity on the object.

POV-Ray fails to accept UTF-8 encoded files with a leading Byte Order Mark.

According to the code it was intended to recognize a leading BOM (or, more precisely, leading non-ASCII code sequences) and automatically switch to UTF-8, so this must be considered a bug rather than a missing feature.

I’ve got an ini file that looks like this:

Post_Frame_Return=U
Post_Frame_Command=notepad.exe

And when I render a scene using that ini file, it renders correctly but then
gives me this error:

Render halted because the post-frame shell-out (’notepad.exe’) requested POV-Ray
to generate a user abort.
Render failed

.....and it doesn’t open notepad.

I’ve unchecked the “Disable Starting Other Programs” and I’ve tried various
variations on what exe to run and whether to do it Pre/Post Frame/Scene, and
nothing has worked.

I’ve had a series of what appear to be a hang up’s. They passed parse, reported some stats and issued the Rendering... message and opened the preview window, but never progressed. They continued to accumulate cpu time until I eventually had to kill -9, softer didn’t work.

I’ve been dismissing them up until now wanted to speak up because I finally got this crash:

29623 Segmentation fault

Here’s some observed behaviors:

In my scene I have a Round_Box_Union with /just/ a pigment that rendered fine, but when I added a wood texture from the distribution includes, it hung up after I tried to transform the texture in any way. Tried other distribution textures ... same thing.

I spent time going through different scenarios looking for a common cause (thinking I’m doing something wrong). Eventually I arrived at the point that I killed a hung render, and restarted the same render with no changes. Sometimes it would render, sometimes not ... I finally got the above mentioned Round_Box_Union to behave with a simple reflective texture, and the rounding parameter had to be above 0.1 ... I settled at 0.125. OK by now you’re thinking WTF right?

No more problems until I accidentally (typo) put an additional light_source at the same location as another light_source. It also hung sometimes, and rendered fine sometimes after a kill ... no SDL changes.

Now I can’t tell you exactly what I was doing when the seg fault happened, but I /do/ know I just restarted the render with no changes. I’m starting to think there’s some kind of instability happening here. I realize that I’m probably the only team member spending any real time with the application, so none of you probably haven’t noticed anything suspicious.

Any comments ... ideas ... suggestions?

How to reproduce:

# An empty directory, an empty source file.
$ mkdir test && cd test && touch test.pov
# Generate the first 24 frames.
$ povray -D +KFF24 +Itest.pov +Otest.png
# Try to generate the 25th frame.
# `25' after `+KFF' can be changed to any integer greater than 24.
$ povray -D +C +KFF25 +Itest.pov +Otest.png

What happens:

==== [Parsing...] ==========================================================
Possible Parse Error: Cannot find file 'test.pov', even after trying to append
 file type extension.
Parse Error: Cannot open input file.
Fatal error in parser: Cannot parse input.
Render failed

OS: Gentoo AMD64 unstable
POV-Ray version: 3.7.0 rc5

Using POV-Ray 3.7 RC6 64bit for Windows
I have problems in the POV-Ray editor with ‘backspace’:

When using backspace at start of line
it does not only kill the return/line feed, but also
everything of the line what’s beneath the upper line.

Sample: (here ‘|’ is used for the current cursor position!)

//--------------------------------------
texture { pigment{ Red }
|         normal { bumps 0.5 scale 0.1 }
//--------------------------------------

hitting backspace results in:

//--------------------------------------
texture { pigment{ Red }| 0.5 scale 0.1 }
//--------------------------------------

and not as expected:

//--------------------------------------
texture { pigment{ Red }|         normal { bumps 0.5 scale 0.1 }
//--------------------------------------

With 3.6.2 and with RC3 (latest old beta I found on my computers)
this was no problem!

I already reported this on 17-Sept-2012 at
http://news.povray.org/povray.beta-test/thread/%3C5056f452%241%40news.povray.org%3E/

As I posted yesterday to the POV bugreports, I observed a bug with the #write directive, having forgotten the closing bracket. I looked a little bit closer and found different behaviours of POV with different array sizes.

With ArrayDim=100 (please look at the attached SDL-code, which is reduced as much as possible and produces only the bug and no scene) one get the Parse Error: “Expected ‘string’, End of File found instead” and the last line is highlighted. With ArrayDim=1024 you get an Stack Overflow and POV crashes.

I observed this at two different core i7 windows machines. On one of them (16 GB RAM, if this is of importance) the threshold between both behaviours was between 300 and 400. Hope this helps.

Best regards,
Michael

Originally resolved in https://bugs.gentoo.org/show_bug.cgi?id=425450.
Attached is a patch with Gentoo-specific code removed.

There are two parts in this issue:

• The newer boost library requires downstream users to explicitly link to the boost system library (-lboost_system).
• The newer boost library replaced TIME_UTC with TIME_UTC_, because glibc added TIME_UTC.

When running make on Linux, the backend source files (and possibly others?) are apparently compiled twice: first from the .../source/backend/ directory, and another time from the .../source/ directory. As an example, here are the corresponding lines for sphsweep.cpp:

g++ -DHAVE_CONFIG_H -I. -I../.. -I../.. -I../../source -I../../source -I../../source/base -I../../unix -I../../vfe 
-I../../vfe/unix -pthread -I/usr/include/OpenEXR    -pthread -I/usr/include  -pipe -Wno-multichar -Wno-write-strin
gs -fno-enforce-eh-specs -s -O3 -ffast-math -pthread -MT sphsweep.o -MD -MP -MF .deps/sphsweep.Tpo -c -o sphsweep.
o `test -f 'shape/sphsweep.cpp' || echo './'`shape/sphsweep.cpp

g++ -DHAVE_CONFIG_H -I. -I..  -I.. -I../source/backend -I../source/base -I../source/frontend -I../unix -I../vfe -I.
./vfe/unix -pthread -I/usr/include/OpenEXR    -pthread -I/usr/include  -pipe -Wno-multichar -Wno-write-strings -fno
-enforce-eh-specs -s -O3 -ffast-math -pthread -MT sphsweep.o -MD -MP -MF .deps/sphsweep.Tpo -c -o sphsweep.o `test 
-f 'backend/shape/sphsweep.cpp' || echo './'`backend/shape/sphsweep.cpp

This is especially annoying on platforms that are rather slow at compiling.

Compiling the sources with clang instead of g++ (on ubuntu 12.10 with boost 1.50)

./configure COMPILED_BY=”your name here <also@email>” LIBS=-lboost_system –disable-io-restrictions CC=clang CXX=clang

there is a few warnings that catch the eyes (and other as well that I dismiss so far, such as cases not covered in switch and empty body in if, or extraneous parentheses in tests):

support/randomsequences.cpp:553:15: warning: field is uninitialized when used here [-Wuninitialized]
                        startIndex(startIndex)
                                   ^
support/randomsequences.cpp:553:15: warning: field is uninitialized when used here [-Wuninitialized]
support/randomsequences.cpp:974:40: note: in instantiation of member function 'pov::PrecomputedNumberGenerator<int>::PrecomputedNumberGenerator' requested here
        SeedableIntGeneratorPtr generator(new PrecomputedIntGenerator(factory, count));
                                              ^
support/randomsequences.cpp:553:15: warning: field is uninitialized when used here [-Wuninitialized]
                        startIndex(startIndex)
                                   ^
support/randomsequences.cpp:984:43: note: in instantiation of member function 'pov::PrecomputedNumberGenerator<double>::PrecomputedNumberGenerator' requested here
        SeedableDoubleGeneratorPtr generator(new PrecomputedDoubleGenerator(factory, count));
                                                 ^
support/randomsequences.cpp:553:15: warning: field is uninitialized when used here [-Wuninitialized]
                        startIndex(startIndex)
                                   ^
support/randomsequences.cpp:1011:43: note: in instantiation of member function 'pov::PrecomputedNumberGenerator<pov::Vector3d>::PrecomputedNumberGenerator' requested here
                return SequentialVectorGeneratorPtr(new PrecomputedVectorGenerator(factory, count));
                                                        ^
support/randomsequences.cpp:553:15: warning: field is uninitialized when used here [-Wuninitialized]
                        startIndex(startIndex)
                                   ^
support/randomsequences.cpp:1056:45: note: in instantiation of member function 'pov::PrecomputedNumberGenerator<pov::Vector2d>::PrecomputedNumberGenerator' requested here
                return SequentialVector2dGeneratorPtr(new PrecomputedVector2dGenerator(factory, count));

Self referencing member in creator does not seems to be great for a reproducible pseudorandom generator (some compiler/architecture might force to 0, other might not... seems bad karma).

                           
             povmscpp.cpp:1875:4: warning: delete called on 'POVMS_MessageReceiver::HandlerOO' that is abstract but has non-virtual destructor [-Wdelete-non-virtual-dtor]
                        delete nodeptr->handleroo;
                        ^
povmscpp.cpp:1877:4: warning: delete called on 'POVMS_MessageReceiver::Handler' that is abstract but has non-virtual destructor [-Wdelete-non-virtual-dtor]
                        delete nodeptr->handler;
                        ^

Maybe just a missing keyword (virtual) in the header file ? Or is it harder ?

shelloutprocessing.cpp:260:28: warning: expression result unused [-Wunused-value]
        for (s = str.c_str(); *s; *s++)
                                  ^~~~

Why “*s++” ? why not just “s++” ?

renderfrontend.cpp:1165:57: warning: trigraph ignored [-Wtrigraphs]
                                        default:                                    t = "(???)";                            break;
 

I guess it’s not an intended trigraph. Might nevertheless perturb some compiler/result.

Quoted strings as parameters to command-line options work on the command line but not in INI files; e.g.:

+i"test.pov"

Root cause has already been identified (actually the problem was found during code inspection) and a fix is under way.

A pigment statement not wrapped in a texture statement does not properly override a pigment previously defined for the object. In the following SDL code:

  #declare PLANE = plane { y,0
    texture {
      pigment { checker color rgb 1 color rgb 0 scale 0.1 }
  } }
  object { PLANE
    pigment { checker color red 1 color blue 1 scale 1.0 }
  }

the scaling of the pigment previously specified for the PLANE object is retained for the new pigment. Compare:

  #declare PLANE = plane { y,0
    texture {
      pigment { checker color rgb 1 color rgb 0 scale 0.1 }
  } }
  object { PLANE
    texture {
      pigment { checker color red 1 color blue 1 scale 1.0 }
  } }

which behaves as expected.

The issue has been around at least since POV-Ray 3.6.2.

The following scene has four spheres with different pigment color & filter settings:

- Left: filter 1
- Right: filter 0

- Top: red 0.0 green 0.5 blue 1.0
- Bottom: red 0.00 green 0.05 blue 0.10 (10% of the above)

Background is set to black, so that we only see the diffuse component of the object’s effective color.

Theoretically, both left spheres should be invisible, as they are fully transmissive (with a filtering effect), but apparently with a high filter setting, reducing an object’s pigment color actually increases the object’s effective diffuse color.

//+w600 +h600

global_settings{ assumed_gamma 1.0 }

camera {
  orthographic
  location  <0,0,-10>
  right 4*x
  up 4*y
  look_at   <0,0,0>
}

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

background { color rgb 0 }

default {
  finish {
    ambient 0
    diffuse 1
    specular 0
    phong 0
    reflection { 0.0 }
  }
}


sphere { <-1, 1, 0>, 0.8 texture { pigment { color rgb <0,0.5,1.0> filter 1.0 } } }
sphere { < 1, 1, 0>, 0.8 texture { pigment { color rgb <0,0.5,1.0> filter 0.0 } } }

sphere { <-1,-1, 0>, 0.8 texture { pigment { color rgb <0,0.5,1.0>*0.1 filter 1.0 } } }
sphere { < 1,-1, 0>, 0.8 texture { pigment { color rgb <0,0.5,1.0>*0.1 filter 0.0 } } }

This bug has been around in 3.6 already.

When using fade_distance and fade_power in combination with area_illumination, the light source fading is not applied to materials with subsurface scattering; see the following code for an example:

#version 3.7;
global_settings {
  assumed_gamma 1.0
  mm_per_unit 10
  subsurface { samples 200,20 }
}

camera {
  right x*image_width/image_height
  angle 30
  location  <0,1.5,-4>
  look_at   <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>]
    }
  }
}

plane {
  y, 0
  texture {
    pigment {
      checker
      color rgb <1.0, 0.8, 0.6>
      color rgb <1.0, 0.0, 0.0>
      scale 0.5
    }
  }
}

light_source {
  <50,50,50>
  color rgb 30
  area_light 5*x,5*y,17,17 adaptive 1 jitter circular orient
  area_illumination on
  fade_distance 10
  fade_power 2
}

cylinder {
  <0,0,0>, <0,0.2,0> 1
  texture {
    pigment { color rgb 1 }
    finish {
      ambient 0
      diffuse 0.7
      specular albedo 0.3
      reflection { 0.3 fresnel }
      conserve_energy
      subsurface { translucency 0.1 }
    }
  }
  interior { ior 1.5 }
}

sphere {
  <0,0.4,0>, 0.2
  texture {
    pigment { color rgb <1,0.6,0.0> }
    finish {
      ambient 0
      diffuse 0.0
      specular albedo 0.8 metallic
      reflection { 1.0 metallic }
      conserve_energy
    }
  }
}

see my post titled: “area light and radiosity problem?” in povray.binary.images [Edit - copied that post’s text here - clipka]

wondering about what’s going on here with this series of images. the radiosity and area light settings are unchanged from image to image, and all I did was radiosity on/off and area_light on/off (btw: using rad_def “Normal” settings)

the 1st image is radiosity only, the 2nd is area light only, and the 3rd combines them:

what’s up with blotches? change #5819/5820 (octree) or maybe something still with area lights?

Currently neither of these pages:

  http://www.povray.org/documentation/view/3.7.0/253/

  http://www.povray.org/documentation/view/3.7.0/90/

mention that the background can be transparent. Any normal user will try to give “background { ... }” a transparent color, see that it doesn’t work, and assume that POV-ray can’t do it.

The pages should mention the +UA command-line option, which enables the transparency.

Included math.inc into scene and recieved this fatal error from povray:

File '/usr/local/share/povray-3.7/include/math.inc' line 248: Parse Error: Expected 'string expression', float function 'vlength' found instead

Appropriate place in math.inc:

245 > #end
246 >
247 > // Distance between V1 and V2
248 > #macro VDist(V1, V2) vlength(V1 - V2) #end
249 >
250 > // Returns a vector perpendicular to V

Running newly-downloaded/newly-compiled POV-Ray 3.7.0, on Linux x86_64 system

There are times when scaling an entire scene up or down is difficult or just not feasible.

One suggestion is a global_settings option.

Also, I’ve noticed that in some situations, such as interactions between certain transparent objects, the epsilon seems to kick in quite early. Perhaps there could be situational or contextual epsilons, such as the “tolerance” of sphere_sweep or the “accuracy” of isosurface.

From synthetic post of Cousin Ricky in p.beta-test, 2013-06-24 circa 3:19 pm (MST)

William F Pokorny anonymous@anonymous.org wrote:
> It seems to be the case the gradient warnings are only generated if the
> isosurface is naked. If it is wrapped in an object as was the case with
> my thread safety example, we get no warnings.

Confirmed. If only I still had the concentration required to investigate
computer code.

#version 3.7;

#ifndef (MG) #declare MG = 40/9; #end
#ifndef (Naked) #declare Naked = no; #end

global_settings
{ assumed_gamma 1
  radiosity {} //force isosurface calculations from all directions
}

light_source { <-3.3125, 7.6250, -5.7374>, rgb 1 }

camera
{ location <0.0000, 1.0000, -5.6713>
  look_at <-0.7969, 1.2000, -0.0598>
  angle 10.7447
}

#include "functions.inc"

#if (Naked)
  isosurface
  { function { f_sphere (x, 0, z, (2660 - 40*y) / 9) }
    contained_by { box { <-80, 31, -24>, <-128, 56, 24> } }
    max_gradient MG
    pigment { rgb <1, 0.75, 0> }
    scale 1/128
    rotate -35 * x
    translate y
  }
#else
  #declare Test = isosurface
  { function { f_sphere (x, 0, z, (2660 - 40*y) / 9) }
    contained_by { box { <-80, 31, -24>, <-128, 56, 24> } }
    max_gradient MG
    pigment { rgb <1, 0.75, 0> }
    scale 1/128
    rotate -35 * x
    translate y
  }
  object { Test }
#end

On the command line, try:

declare=MG=1 declare=Naked=1

and

declare=MG=1 declare=Naked=0

To lose the warning, I had to declare the isosurface. Just wrapping the naked
isosurface in an object{} generated a warning.

Further analysis

if((Stage == STAGE_SHUTDOWN) && (mginfo->refcnt == 0))

Using an end value of 1048576 or larger in a #for loop will cause the last iteration to be skipped, as can be demonstrated by the following code:

#declare N = 2000000;
#debug concat(”N = “,str(N, 0,50),”\n”)
#debug concat(”N-5 = “,str(N-5,0,50),”\n\n”)
#for (I, N-5, N, 1)

#debug concat("I   = ",str(I,0,50),"\n")

#end

(The limit was observed with a Win64 build; other builds may exhibit other limits or might even work fine, depending on the floating point engine used.)

As this limit is still far below the numeric precision limit, and a corresponding #while loop works fine with much higher values, this must be considered a bug rather than an inevitable limitation.

The bug can be tracked down to a faulty condition in tokenize.cpp, Parser::Parse_Directive(), CASE(END_TOKEN), case FOR_COND:

    if ( ((Step > 0) && (*CurrentPtr >= End + EPSILON)) ||
         ((Step < 0) && (*CurrentPtr <= End - EPSILON)) )

which should instead be:

    if ( ((Step > 0) && (*CurrentPtr > End + EPSILON)) ||
         ((Step < 0) && (*CurrentPtr < End - EPSILON)) )

Blobs are currently limited to 1,000,000 components (with each cylindrical component counting as three: one cylinder + two end hemispheres); this limit may have served a historic purpose, but is now entirely arbitrary: The remaining code is limited only by the available RAM and the numeric limits of the int data type. The arbitrary maximum components limit per blob should therefore be removed.

Aside from unnecessarily limiting the power of the blob component, another drawback of the current test is that it is only performed after parsing of all the blob’s components, potentially hours after the limit had actually been reached.

I’ve recently been working with the netpbm ppm format and I have hit what I believe to be a bug in the way ppm files are read – very likely a bug in all netpbm formats. I am aware of the long standing povray issue with the netpbm file formats header where the height and width need to be on the same line as the magic number though that is not a requirement of the official format. This bug is different.

Namely in working with a larger number of ppm files I hit cases where a few would fail with the message : “Possible Parse Error: Unexpected EOF in PPM file” though the ppm files are fine. What is happening is that the first byte of data after the line feed (LF) (Ubuntu linux 12.04) happens to have a carriage return (CR) value.

The code which is set up to interpret the netpbm headers is reading a lines with “file→getline (line, 1024);” and this line reading code is pulling in the first byte of data with the CR value as part of the line. When the read by binary data, 8 or 16 bits at a time, starts, the povray read code is offset into the data by one byte too many.

The result from 10,000 meters, if input values were completely random file to file, would be netpbm read fails for size that make no sense in 1/256 files. In practice & depending on data some might never see fails while an unfortunate few might almost always fail.

I’d make some argument any CR following a LF character should not be pulled in as part of the line read even on windows/dos systems where CRLF is the usual line termination order. I think though the real fix is better netpbm header reading code which more strictly breaks apart the header on the first whitespace character doing the last depth break, aware of the file size, so it can decide what portion of any valid sequence of whitespce characters after the decimal depth value is data and not whitespace.

The attached tarball when unpacked has both a passing and failing case. To run “povray fails.pov” or “povray works.pov”. The only difference between the two ppm files if the fails.ppm data is all 0x0D while works.ppm data bytes are all 0x0C. The image rendered is meaningless.

Thanks for your time.
Bill P.

After a long parse period and a relatively quick rendering, POVray gets stuck at 99% when rendering the attached file.

Rendered at 6144x3072px with antialiasing set to 0.3.

Can anyone confirm?

As the following scene demonstrates, the “inverse” keyword produces unexpected results with quadrics.

Left: a sphere primitive as reference
Right: a sphere-shaped quadric primitive (sphere-shaped)

Top: plain
Bottom: inverse

The objects are clipped in half to better demonstrate the effect. Regular texture is shown in white, interior_texture in red; the surface normal of a selected point (blue) as returned by trace() is shown in green.

Note how the sphere’s surface normal, as well as the textures, are flipped when “inverse” is used (this is the intended standard behaviour of all objects), while the quadric’s normal and textures erroneously remain uchanged.

// +w800 +h600

#version 3.7;

global_settings{ assumed_gamma 1.0 }

#default{ finish { ambient 0.1 diffuse 0.9 specular 0.5 }} 

camera {
  perspective
  angle 40
  right     x*image_width/image_height
  location  <0,0,-10>
  look_at   <0,0,0>
}

light_source{ < 1000,3000,-3000> color rgb 1 }

background { color rgb 0.5 }

#declare T_White = texture { pigment { color rgb   1 } }
#declare T_Red   = texture { pigment { color red   1 } }
#declare T_Green = texture { pigment { color green 1 } }
#declare T_Blue  = texture { pigment { color blue  1 } }

#declare TopLeft     = sphere { 0, 1 }
#declare BottomLeft  = sphere { 0, 1 inverse }

#declare TopRight    = quadric { <1,1,1>, <0,0,0>, <0,0,0>, -1 }
#declare BottomRight = quadric { <1,1,1>, <0,0,0>, <0,0,0>, -1 inverse }

#macro Mac(Obj, P, D)
  union {
    #local N = <0,0,0>;
    #local O = <-0.6,0.4,-10>;
    #local Q = trace(Obj, O, D, N);
    #if (vlength(N) > 0)
      sphere { Q, 0.05 texture { T_Blue } }
      cylinder { Q, Q + N, 0.02 texture { T_Green } }
    #else
      cylinder { O, O + D*10000, 0.02 texture { T_Red } }
    #end
    object { Obj texture { T_White } interior_texture { T_Red } clipped_by { box { <-1,-1,-1>, <0,1,1> rotate y*30 } } }
    translate P
  }
#end

Mac(TopLeft,     <-1.2, 1.2, 0>, z)
Mac(TopRight,    < 1.2, 1.2, 0>, z)
Mac(BottomLeft,  <-1.2,-1.2, 0>, z)
Mac(BottomRight, < 1.2,-1.2, 0>, z)

As the following scene demonstrates, the “inverse” keyword produces unexpected results with fractals.

Left: a sphere primitive as reference
Right: a julia fractal

Top: plain
Bottom: inverse

The objects are clipped in half to better demonstrate the effect. Regular texture is shown in white, interior_texture in red; the surface normal of a selected point (blue) as returned by trace() is shown in green.

Note how the sphere’s surface normal, as well as the textures, are flipped when “inverse” is used (this is the intended standard behaviour of all objects), while the fractal’s normal and textures erroneously remain uchanged.

// +w800 +h600

#version 3.7;

global_settings{ assumed_gamma 1.0 }

#default{ finish { ambient 0.1 diffuse 0.9 specular 0.5 }} 

camera {
  perspective
  angle 40
  right     x*image_width/image_height
  location  <0,0,-10>
  look_at   <0,0,0>
}

light_source{ < 1000,3000,-3000> color rgb 1 }

background { color rgb 0.5 }

#declare T_White = texture { pigment { color rgb   1 } }
#declare T_Red   = texture { pigment { color red   1 } }
#declare T_Green = texture { pigment { color green 1 } }
#declare T_Blue  = texture { pigment { color blue  1 } }

#declare TopLeft     = sphere { 0, 1 }
#declare BottomLeft  = object { TopLeft inverse }

#declare TopRight    = julia_fractal{ <-0.083,0.0,-0.83,-0.025> quaternion sqr max_iteration 8 precision 20 scale 0.9 }
#declare BottomRight = object { TopRight inverse }

#macro Mac(Obj, P, D)
  union {
    #local N = <0,0,0>;
    #local O = <-0.6,0.4,-10>;
    #local Q = trace(Obj, O, D, N);
    #if (vlength(N) > 0)
      sphere { Q, 0.05 texture { T_Blue } }
      cylinder { Q, Q + N, 0.02 texture { T_Green } }
    #else
      cylinder { O, O + D*10000, 0.02 texture { T_Red } }
    #end
    object { Obj texture { T_White } interior_texture { T_Red } clipped_by { box { <-2,-2,-2>, <0,2,2> rotate y*30 } } }
    translate P
  }
#end

Mac(TopLeft,     <-1.2, 1.2, 0>, z)
Mac(TopRight,    < 1.2, 1.2, 0>, z)
Mac(BottomLeft,  <-1.2,-1.2, 0>, z)
Mac(BottomRight, < 1.2,-1.2, 0>, z)

The following scene demonstrates how media sampling method 3 gives inaccurate results with scattering media.

The scene shows four spheres with uniform media, using (left to right) sampling methods 1, 2 and 3 with default settings, and sampling method 3 with high minimum sample count, respectively.

Note how changing the sample count significantly affects the result, despite the media being uniform.

Code analysis shows that the root cause is an underestimation of the extinction effect on the light scattered by the media, corresponding in order of magnitude to half the distance between mandatory samples (as defined by minimum sample count).

The effect also leads to visible artifacts when nesting hollow objects inside the media, as can be demonstrated by un-commenting the four smaller spheres.

#version 3.7;

camera {
  perspective angle 25
  location  <0.0 , 0.0 ,-20.0>
  right     x*image_width/image_height
  look_at   <0.0 , 0.0 , 0.0>
}

light_source {
  <0,3000,-3000> color rgb 1
}

background { color rgb 0.5 }

plane {
  <0,1,0>, -1
  texture { pigment { checker color rgb<1,1,1>*1.2 color rgb<0.25,0.15,0.1>*0 } }
}

#declare T_Transparent = texture {
  pigment { color rgbt <1,1,1,1> } finish { diffuse 1 }
}

sphere { <-3,0,0>, 1.00 
  texture { T_Transparent }
  hollow
  interior {
    media {
      scattering { 1 color rgb 2 extinction 1 }
      method 1
    }
  }
}

sphere { <-1,0,0>, 1.00 
  texture { T_Transparent }
  hollow
  interior {
    media {
      scattering { 1 color rgb 2 extinction 1 }
      method 2
    }
  }
}

sphere { <1,0,0>, 1.00 
  texture { T_Transparent }
  hollow
  interior {
    media {
      scattering { 1 color rgb 2 extinction 1 }
      method 3
    }
  }
}

sphere { <3,0,0>, 1.00 
  texture { T_Transparent }
  hollow
  interior {
    media {
      scattering { 1 color rgb 2 extinction 1 }
      method 3
      samples 100
    }
  }
}

/*
sphere { <-3,0,0>,0.8 texture { T_Transparent } hollow }
sphere { <-1,0,0>,0.8 texture { T_Transparent } hollow }
sphere { < 1,0,0>,0.8 texture { T_Transparent } hollow }
sphere { < 3,0,0>,0.8 texture { T_Transparent } hollow }
*/

When using mesh_camera type ‘0’

The first line of the mesh output seems to be repeated resulting in incorrect light colour values.

If the first line of the texture is skipped then the values seem to be correct.

Height=36084

[640×360, AA 0.3]
Width=640
Height=36084
Antialias=On
Antialias_Threshold=0.3

should be:

[640×360, AA 0.3]
Width=640
Height=360
Antialias=On
Antialias_Threshold=0.3

On Windows 7 and newer operating systems, some programs are able to display their progress in the taskbar buttons.

Here is an example of Chrome downloading something and showing the progress in the taskbar:

http://www.winbeta.org/sites/default/files/news/oldfashinoned.jpg

Here is an example with Paint.NET instead:

http://www.getpaint.net/images/pdn351_superbarProgress.png

I think this feature would use fewer CPU resources than a) minimizing/maximizing the whole application window each time you want to check progress, or b) hovering the mouse over the taskbar button to show the thumbnails.

#fopen directive w/o OPEN_TYPE (yeah, I forgot it, some other languages have ‘read’ as default value)

expected behavior:
Parse error msg “line XXX, OPEN_TYPE missing in #fopen directive”, then stop.

observed behavior:
crash - Segfault err (core dump) in Parsing stage

minimal working example attached