POV-Ray

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

Hi,

I think I may have found a bug in the subsurface/radiosity features of Povray 3.7 attached image showing the issue and sample files required to reproduce. The original files (on povray forum images thread) had different radiosity settings but these ones show the problem and only take a few seconds to render the image without AA so probably better for bug fixing/testing etc.

Thanks

Sean

There can be square (32×32) blotches in partially transparent objects.

global_settings {
   max_trace_level 10
}

camera { 
   location <-30,10,5> 
   look_at <0,0,0> 
   angle 25 
}


light_source { 
   <-100,30,70> 
   rgb 1 
}

difference { // make a dome
  sphere { <0,0,0> 5 }  // ball
  sphere { <0,0,0> 4.9 } // hollow interior
  box { <-6,-6,-6> <6,1,6>  pigment { rgb <0,0,0> }}  // chop off bottom half
  pigment { rgbt <1,1,1,0.675> }
}

box { 
   <-6,-6,-6>, <6,0.99,6> 
   pigment { rgb <1,1,1> } 
   rotate <0,45,0>
} // sit it on a box

This item may need to be merged with item FS#81. This is another sphere sweep bug, though they are of different spline types.

The code is

#include "colors.inc"

camera {
  location  <0, 0.0, -4.0>
  direction 1.5*z
  right     x*image_width/image_height
  look_at   <0.0, 0.0,  0.0>
}

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


#declare i_start = 0;
#declare i_stop = 3;
#declare i_step = 0.05;
#declare i_inc = i_start;
sphere_sweep {
  linear_spline                 // linear curve

  (i_stop - i_start)/i_step + 1,    // number of specified sphere positions
#while(i_inc<=i_stop)
  
  #declare y_coor = 0.23*sin(7.1*i_inc);
  <i_inc, y_coor, 0>, 0.05
        #declare i_inc = i_inc + i_step;
 
        
#end

pigment{color Orange}

}

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.

Suggestion:

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

Add a way to get and set font metrics.

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

Thanks!!

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

If the image is more than 1270 pixels wide or more than 720 pixels high, animation fails with a segmentation fault during the second rendered frame. This happens after parsing is complete and the .pov-state file is created. The last message line is the “[Rendering...]” line. (There is also a separate, but possibly related, issue that the output display does not work for these renders.)

On one occasion, POV-Ray hung, and I had to ctrl-Z kill -9 out of it.

On another occasion, instead of the segmentation fault, I got the message:

povray: xcb_io.c:140: dequeue_pending_request: Assertion `req == dpy->xcb->pending_requests' failed.
Aborted

There is no crash when -D is used.

I have not run an animation this large in Windows, so I don’t know if it’s a problem there.

Neither problem occurs in POV-Ray 3.6.1.

I used the following source code:

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

Platform

Libraries

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?

I got a 29023 Segmentation fault ... but it was NOT repeatable. I reran the render job repeatedly and it displayed appropriate error message. I had renamed a texture identifier but missed an occurrence inside texture_map.

FYI: I did a build off the depot last evening.(21:13)

I would like to suggest an additional feature regarding splines. POV-Ray’s spline objects (spline {}) are very useful to create animation paths as a function of time from reference points; however, in many cases you do not only need a position to place an object correctly, but also its velocity etc., e.g. if you are animating a car moving along a spline you do not only need to know where the car is at a given clock value but also in which direction it is going. If you want to rotate the wheels correctly you even need to know how this direction is currently changing.

In a nutshell, if you are using splines to create an animation path, you might not only need the spline value itself, but also the value of its first and second derivative. So I suggest adding an SDL capability to access these values like it is possible to access the spline value for a given parameter.

I do not think it would be too difficult to add a feature like this as far as the backend is concerned, since for computing a (cubic) spline you need the first and second derivatives anyway. (They are probably not being stored separately, but a polynomial is not that hard to differentiate.)

Indeed I do not know how an SDL language construct for it should look like (i.e. whether to use ' and ‘’ like in mathematics or a second spline function parameter).

The following line in the lathe1a.pov, lathe1b.pov, and lathe1c.pov appears to have an error in it.

  <3.6.9>, <4, 1.1>, <3.4, 2>, <3, 1>, <2, 1>,

Although it works in version 3.6, only in 3.7 does a render time error ocurr.

Scene source should be adjusted to the following

  <3.6, 0.9>, <4, 1.1>, <3.4, 2>, <3, 1>, <2, 1>,

When right-clicking on a tab in the editor window a list of options should appear, such as:

* Close
* Close all but this
* Save
* Save as
* Print

See Notepad++, EditPad Lite, and Firefox for examples.

original posting from povray.beta-test:

I get this error message:
"Parse Error: bad allocation  Render failed"
- after the code below has been running for about 3 seconds.

// ===== 1 ======= 2 ======= 3 ======= 4 ======= 5 ======= 6 ======= 7

#version 3.7;

#while (true)
  #local Fn = function { transform { translate <0, 0, 0> } }
  #undef Fn
#end // while

// ===== 1 ======= 2 ======= 3 ======= 4 ======= 5 ======= 6 ======= 7

I'm using POV-Ray for Windows - Version 3.7.0.RC3.msvc9-sse2.win32
The operating system is Windows XP.

With the code above, the error messages has so far appeared every time
right after 3318K tokens have been parsed. But with other versions of
my code, the error message does not always show up. (Sometimes the
render finishes and sometimes the parsing stops at different "times".)

[...]

Other users report no error message, but memory consumption rising to about 1.2 GB.

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?

When aborting a render when there are unfinished blocks among finished ones, under certain conditions some of those blocks are skipped when continuing the render later.

Automatic removal of user-specified bounding boxes cannot be disabled in current POV-Ray 3.7 betas; the Remove_Bounds ini file setting and the +/-UR command line option are silently ignored.

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.

Reflective texture maps can cause a stack overflow crash.

sphere{0,1
  texture{
   bozo
   texture_map{
    [0 pigment{rgb 0}]
    [1 pigment{rgb 0} finish{reflection 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?

Currently, output image is buffered using POV-Ray’s RGBFT color model and floating point values, leading to a memory consumption of 20 bit per pixel. This is an unproportionally large memory footprint, given that the only further processing performed on the buffered data is conversion of the data to the desired output file format, which will typically use only 3 bytes per pixel (at most 12 bit per pixel).

The situation can be improved by choosing the output image buffer container based on the desired output file format and parameters. To this end, the following code changes should be made:

• Bundle image file format handler code into classes (typically one per file format)
• Include a method to determine the best data container type for the image buffer
• Instantiate the desired image file format handler object prior to rendering, querying the handler object for an image buffer

In addition to picking a suitable image data container from the already existing palette, careful design might also allow to use custom containers to directly pass the data to a library (in case the library provides its own buffering anyway), or write it directly to the output file (e.g. when writing image data to stdout). To make this compatible with multithreaded rendering, the following changes would have to be made:

• Add code to detect when a row of SMP blocks has been finished, and call a certain method on the image handler object
• Design the custom containers in such a way that they can buffer any number of unfinished SMP block rows as needed

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.

Array.inc and subsurface.pov are in read only mode, they probably should have normal permissions.

Versions of POV-Ray prior to 3.7 had the ability to write the image output as a stream to STDOUT. This was particularly useful in unix as it allowed POV-Ray output to be directly piped to other processes.

The introduction of SMP and the associated non-linear generation of pixels complicates stream output to the extent that it is not currently available in v3.7.

At a minimum 3.7 must at least be able to write the completed image to STDOUT after a render - this is not an optimal solution but is better than nothing. Ideally however once entire lines are complete (most likely this will occur in batches due to the block nature of the render subdivision) these lines will be written immediately to STDOUT (after possibly being processed through the appropriate image format routines).

NB currently the image format routines are not invoked until the entire render is completed, so to do this would be a significant modification. However if we limit real-time stream output to “simple” non-compressed formats (e.g. PPM), it would not be overly difficult, and from the point of view of Unix-like operating systems (where the piping feature is most useful), if the data is in PPM format it can easily be transformed into anything else.

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.

Tested with beta 40. Also affect version 3.6.1 as reported in the discution group.

When using radiosity and emissive media. Any object, or part of, that is inside the media container is not affected by the illumination comming from the media.

When using scattering media, the light scattered by the media also don’t affect objects that are inside it’s container.

http://news.povray.org/povray.newusers/thread/%3C4cf8fe22%241%40news.povray.org%3E/

A scene of a hollow sphere viewed from the inside:

difference {
    sphere { 0, 100 }
    sphere { 0, 99 }
    pigment { rgb 1 }
    finish { ambient .4 }
}

global_settings {
    radiosity {
        error_bound .1
    }
}

Rendering produces dark splotches at the centers of the pretrace blocks, as shown in the attached image. Blocks rendered earlier have darker splotches. They also differ in shape between renders even with +HR (but not with +WT1).

Turning “always_sample” on, changing “pretrace_end” to 0.01, or increasing “count” past 1000 makes them imperceptibly faint (they can still be seen by increasing image contrast).

This is possibly a bug, as 3.6 doesn’t produce these artifacts regardless of additional settings.

povray.beta-test thread

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)

the quick_color feature doesn’t work when +qN or Quality=N is set to 5 or below

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.