Reported in p.beta-test by James Dietrich (2013-12-12)

when the display window must be scaled (because one or both dimensions are larger than the actual screen), the ratio of scale might be too large in some occasion, performing a memory corruption in two places and usually crashing povray.

How to reproduce, with a 1920×1080 display (or 1920×1200):

povray +W2596 +H1003 +Ispiral.pov +Ospiral.png +D

In gif.cpp (source/base/image), circa line 150:

			case ',': /* Start of image object. Get description. */
				for (int i = 0; i < 9; i++)
				{
					if ((data = file->Read_Byte()) == EOF)
						throw POV_EXCEPTION(kFileDataErr, "Unexpected EOF reading GIF file");
					buffer[i] = (unsigned char) data;
				}

				/* Check "interlaced" bit. */
				if ((buffer[9] & 0x40) != 0)
					throw POV_EXCEPTION(kFileDataErr, "Interlacing in GIF image unsupported");

The loop reads the 9 bytes of the Image Block, but is testing the tenth byte for interlacing.

Reference for image format: http://www.onicos.com/staff/iz/formats/gif.html#ib

When the gif is generated by Gimp, the Image block is preceded by the comment block which default to “Created with GIMP”... the comment is read in the buffer, and the “i” will be in buffer[9], any letter after @ will indeed block povray.

This bug was not present in 3.1g nor in 3.6.1 (due to different source to handle gif).

If not created by Gimp, or with shorter comment, the content of buffer[9] is more random, yet it might trigger the bug depending on the previous blocks and their handling.

Due to a recent thread in povray.general (7th September 2013), I dive
into the code of height field creation.

There is 2 TODO in source/backend/support/imageutil.cpp, for
image_height_at() (circa line 512)

The first one is about using the index of palette-image: As far as *257
would indeed perform a better job to cover the full range than *256, it
would break backward compatibility with previous versions of povray (3.6
included) which only promoted the index as the Most significant byte,
keeping the least one at 0.

But on the second one, the new formula is plain wrong: (r*255+g)*255
should be (r*256+g)*255.
In previous versions, r*255 was the Most significant byte, and g*255 was
the least one.
Ergo, the value was r*255*256 + g*255, which can and should be only
factored as (r*256+g)*255;

I know it is damn late in the release schedule, but can that be either
be fixed before final official delivery or a memo added to the release
note that it would be fixed later and backward-bug will not be
maintained for that specific point (using rgb-8 or less bit per
channel-image for height field)

(it was not bugged in 3.6.1 nor before, it’s just that tiny little bit
of 3.7 that would should that bug)

If you look carefully at the attached pictures (povray +I... +H700 +W700 +A0.01) of scene and scene36, there is a significant difference at the top.
With 3.6, it matched exactly (hence the noise on the top pixels row) the view.
With 3.7, it cannot reach the top and leave a white area
(another difference is the slope on the side are also a bit more lower with 3.7, easier to spot when alternating the display of both pictures)

If you want to regenerate hf.png, it was rendered with povray 3.7RC7, +W400 +H400 +A0.01 +Ihf.pov

The white line at the bottom is expected, as the minimal value of the height field is “full green”

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))

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.

I reinstall a system, (so ~/.povray was not existant), and then
installed povray from sources, as a normal user (excepted the
installation step):

$ ./configure ...
$ make
$ make check
$ sudo make install

I find these steps pretty much standard.

The problem I’m noticing is that the $HOME/.povray hierarchy get owned
by root (hey, it’s *MY* directory !). There is a chown in the Makefile
for the target files (povray.ini & povray.conf), as well as subtree but:

* povowner & povgroup are hard coded to 0 (I would expect a copy of the
owner & group of $HOME, wouldn’t I ?)

For getting povowner, I would suggest `stat -c “%u” $HOME`
For povgroup, `stat -c “%g” $HOME`

Are they portable enough ? (I could ask on Monday a Solaris system, but
I do not have bsd and the other flavours of unix)

(Stat is in section 1 of man, part of gnu coreutils, /usr/bin/stat)

Side note: This is fine to install for the local user, but new later
users could benefit also from a ~/.povray/3.7/ subtree ; what about also
filling the /etc/skel (when available) ? (and in /etc/skel, root owner
is fine!)

Hopefully platform specific, other ports are welcome to check their scaling code.

Reported originally in p.beta-test (28 january 2012) by Cousin Ricky (email dropped)

Symptom: crash on start of second frame rendering
Environment: Unix, with display of rendered picture, rendered picture does not fit at 1:1 on the display

Demo (adjust the H/W to your setting to get them larger, both or any of them):

global_settings { assumed_gamma 1 }
light_source { <-1, 1, -1> * 1000, rgb 1 }
sphere { 2.5 * z, 1 pigment { red 1 } }

povray +H2000 +W2000 +KI0 +KF1 +KFI0 +KFF10 code.pov

Lines 1217, 1241 and 1242 of benchmark.cpp must be change to use #declare instead of local for A and its elements.
(because A is returned by the macro)

	"#macro L_GetVN(ResSpl)\n"
	"   #local I = 0;\n"
	"   #declare A = array[ResSpl+1][2]\n"                      //  <============== this is line 1217
	"   #while (I<=ResSpl)\n"
	"      #local P0 = 0+<FnA(I/ResSpl), I/ResSpl, 0>;\n"
	"      #if (P0.x=0 & P0.z=0)\n"
	"         #local P0 = <1e-25,P0.y,1e-25>;\n"
	"      #end\n"
	"      #if (I=0)\n"
	"         #local P1 = 0+<FnA(((I-0.5)/ResSpl)), I/ResSpl, 0>;\n"
	"         #local P2 = 0+<FnA(((I+0.5)/ResSpl)), I/ResSpl, 0>;\n"
	"      #else\n"
	"         #local P1 = P2;\n"
	"         #local P2 = 0+<FnA(((I+0.5)/ResSpl)), I/ResSpl, 0>;\n"
	"      #end\n"
	"      #local P3 = vrotate(P0,<0,1,0>);\n"
	"      #local P4 = vrotate(P0,<0,-1,0>);\n"
	"      #local B1 = P4-P0;\n"
	"      #local B2 = P2-P0;\n"
	"      #local B3 = P3-P0;\n"
	"      #local B4 = P1-P0;\n"
	"      #local N1 = vcross(B1,B2);\n"
	"      #local N2 = vcross(B2,B3);\n"
	"      #local N3 = vcross(B3,B4);\n"
	"      #local N4 = vcross(B4,B1);\n"
	"      #local N = vnormalize((N1+N2+N3+N4)*-1);\n"
	"      #declare A[I][0] = P0;\n"                               // <============== this is line 1241
	"      #declare A[I][1] = N;\n"
	"      #local I = I+1;\n"
	"   #end\n"
	"   A\n"
	"#end\n"

Same update should also be reported into the distributed scene benchmark.pov

How to do it: (with raddem.ini & raddem.pov from distributed scenes, copied in local directory)

1. run “povray raddem.ini” until frame 6 or more (irrelevant, at least frame 1 & 2 are needed), interrupt the render.
2. restart “povray raddem.ini +C”

It fails at frame 2 with
Possible Parse Error: Cannot find file ‘raddem.pov’, even after trying to append
file type extension.
Parse Error: Cannot open input file.
Fatal error in parser: Cannot parse input.
Render failed

The detection of frame 1 is fine.

in the sample scenes, animations/raddem/raddem.ini is not parsable by current versions of povray. (3.7RC3 and upto #5476)

Radiosity= is a gone away option.(from a bit of time in the 3.7 branch)

in change #3319, csg got a new computation for its weighted textures.

But I’m confused by the computation of the weight: (circa end of csg.cpp file)

COLC weight = 1.0f / min(COLC(textures.size() - firstinserted), 1.0f);

I would have used a max() rather than a min().

It is transparent when there is only one texture, but:

• should there be no texture (an error...): it would be a division by 0
• should there be more than 1, the weight of each would be 1. which is without consequence UNLESS there is already some other textures in the list. The right value (from previous code) was 1/n

Or did I get a confusion about min() ?

min(0,1) == 0
min(4,1) == 1

Using max would protect against the division by 0 and the right value when multiple textures are used.

Any thought ?

From post in povray.general (circa 29 september 2010: “Maximum Resolution of Renders?”)

The ultimate goal would be a 41000×41000 image. However each time I have attempted to render that Pov-Ray has crashed on
me. Even when using a single, simple test object (a plain white sphere that
should use a single pixel). So I think this is running into a program limitation
at present.

It won’t be for the faint hearted: a 30500 x 30500 does still produces the bug, but you’d better have 24 GB of true ram to test it.
(it’s a render of a few “real” minutes if you do not swap, for any very quick scene (a 305 x 305 in 0.117s moved to 220s for 30500×30500 on my system when corrected))

With core-dumped enable, the issue is pointed in the creator of PixelContainer.
The problem is due to the resize() parameter: despite the parameter being a size_t (8 bytes long on 64bits), the computation ( h * w * 5 ) use unsigned int for h & w (and signed int for 5).

As a consequence, the value of resize is computed as a signed int... havoc might happen when the signed bit (#31) is propagated to the #63 to #32 of size_t... vector does not enjoy a negative value for resize (and destroy itself: no iterator on coming soon call! hence the crash when the values in the vector are to be initialised)

30500²: (in hex)

1 15 3C 71 50 floats
4 54 F1 C5 40 bytes

Basic solution: promote the 5 to an unsigned long, forcing the computation to happen on unsigned long, avoiding promotion of silly sign-bit, and keeping the resize’s value as a good number.

aka: resize( w * h * 5) becomes resize ( w * h * 5ul )

This solution has been tested and seems fine (it’s just that in base/image/image.cpp, there is a lot of resize()!).
For all resize(), the “ul” must be added. (and that means also that resize( w * h ) must be rewritten as ( w * h * 1ul ). )

Include file golds.inc still provides warnings when parsed, a shame for a standard include file.
(colors.inc is ok, I did not test the other includes)

File '/usr/local/share/povray-3.7/include/golds.inc' line 118: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 119: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 129: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 130: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 140: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 141: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 151: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 152: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 162: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.
File '/usr/local/share/povray-3.7/include/golds.inc' line 163: Parse Warning:
 Expected pure RGB color expression, unexpected filter and transmit components
 will have no effect.

Compiled on linux (revision #5066),
./configure COMPILED_BY=”###” –disable-io-restrictions

the command: povray –benchmark

is failing:
Failed to parse INI file

povray –version

I/O restrictions:          disabled
X Window display:          enabled (using SDL)
Supported image formats:   gif tga iff ppm pgm hdr png jpeg tiff openexr
Unsupported image formats: -

Build architecture:  x86_64-unknown-linux-gnu
Built/Optimized for: x86_64-unknown-linux-gnu (using -march=native)
Compiler vendor:     gnu
Compiler version:    g++ 4.4.3
Compiler flags:      -pipe -Wno-multichar -Wno-write-strings -fno-enforce-eh-specs -s -O3 -ffast-math -march=native -pthread 

Installation script (from sources) when run with a classical “sudo make install” would create povray.ini & povray.conf in $HOME/.povray/3.7 (so far so fine) with the owner as root and the permission to readonly for the real user.

Same goes for the owner of the 3.7 directories tree : .povray & .povray/3.7 are created with root owner, despite being in $HOME of the performing user.

Please fix ?

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.

Reported for freebsd 7.2 (current production version, true for previous version, unknown for 8.0 in beta now)

freebsd does not provide CLOCK_PROCESS_CPUTIME_ID
(even if CLOCK... is posix).

As a consequence, compilation of the unix-source is currently not possible for freebsd target.

Might be a simple selection for Change 4356 ?
(assuming a relevant test in ./configure)
(getrusage() seems available on freebsd, but does it provide the pieces of information needed, I do not know that code good enough to assert that)

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.

Beta 32, compiled from source on Linux/Ubuntu, amd64.

The random “window display lock” is back.
(as the previous “solution” was to get no window display usable, that’s not so bad).

What is it: sometime, when the rendering window is activated, povray just draw the frame
of the window, paint it black, does not display anything else but seems to perform the
rendering in separate threads. Whenever the mouse move over the frame of the window, it
unlock the updating process and big parts of the rendered image pop up.

What it is not fine: if you do not move the mouse over the window, povray will just stall.
This is more a problem for animation rendering, as getting the display might be a wanted
bonus to monitor the rendering images, and you just fall into that lock: your expected
night rendering could very well be suspended on the first frame.
Moreover, the “move the mouse over” works only for local display. In previous beta (not
yet checked with 32), with a remote display, there was no way to unlock povray.