If pretrace_start is set below pretrace_end, POV-Ray will run a high number of pretrace steps (without changing pretrace resolution).

polygon objects comprised of multiple “sub-polygons” don’t work properly if start/end points of sub-polygons do not exactly match, as can be demonstrated by the following code:

#default { texture { pigment { rgb 1 } finish { ambient 1.0} } }

camera {
  orthographic
  up 3.5*y
  right 3.5*x*image_width/image_height
  location  <0,0,-4>
  look_at   <0,0,0>
}

polygon { 8,
  // outer triangle
  0.70 * < cos(  0 *pi/180),sin(  0 *pi/180),0>
  0.70 * < cos(120 *pi/180),sin(120 *pi/180),0>
  0.70 * < cos(240 *pi/180),sin(240 *pi/180),0>
  0.70 * < cos(360 *pi/180),sin(360 *pi/180),0>

  // inner triangle
  0.35 * < cos(  0 *pi/180),sin(  0 *pi/180),0>
  0.35 * < cos(120 *pi/180),sin(120 *pi/180),0>
  0.35 * < cos(240 *pi/180),sin(240 *pi/180),0>
  0.35 * < cos(360 *pi/180),sin(360 *pi/180),0>
}

Note that the end points /should/ be identical. There are however some minor rounding differences, which mess up polygon computations. Compare with the following code, which leads to the desired results:

polygon { 8,
  // outer triangle
  0.70 * < cos(  0 *pi/180),sin(  0 *pi/180),0>
  0.70 * < cos(120 *pi/180),sin(120 *pi/180),0>
  0.70 * < cos(240 *pi/180),sin(240 *pi/180),0>
  0.70 * < cos(  0 *pi/180),sin(  0 *pi/180),0>

  // inner triangle
  0.35 * < cos(  0 *pi/180),sin(  0 *pi/180),0>
  0.35 * < cos(120 *pi/180),sin(120 *pi/180),0>
  0.35 * < cos(240 *pi/180),sin(240 *pi/180),0>
  0.35 * < cos(  0 *pi/180),sin(  0 *pi/180),0>
}

Code inspection shows that the polygon insideness testing code tests for precise equality of the points, whereas the general policy of POV-Ray is to accept slight rounding differences.

I rendered attached .pov file with both 3.62 and 3.7RC1, and got different output between them.
In 3.7RC1, it looks like no_reflection option of the black sphere doesn’t work.

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)

couple of observations:

if no photons are gathered (hey it happens ... my typo) when attempting to save a photon map the warning message just indicates that it couldn’t save the map, maybe the message could be enhanced to say something like: No photons were gathered so no map information was saved. At first I thought something had changed in my I/O restrictions (I’m writing to an image directory not current or work directory)

when reading a previously saved photon map there is no indication that it was read in other than the end stats showing a small amount of photon time. I don’t recall but didn’t v3.6 indicate that the a previously saved map was being used? Just for the heck of it I moved the map file aside and it did prove to me that it was indeed being input. Some sort of message at the time the file is read in might be helpful.

Using interpolated image_maps in functions results in pixel-sized dot-artifacts when using the functions back into pigments.

This problem doesn’t shows using the same code on POV-Ray 3.6.

I qualified it as “low severity” because is not going to happen to most users: it will show only when using some advances techniques, for example when you want to decompose an image_map into the RGB components, perform operations, and mixing them back with an averaged pigment (example attached).

‘povray -H10 -W20 myscene.pov’ will generate a file with a picture 10 pixels high and 20 pixels wide, BUT in the message pane it displays

Image resolution.....20 by 10 (rows 1 to 20, columns 1 to 10)

instead of

Image resolution.....20 by 10 (rows 1 to 10, columns 1 to 20)

or

Image resolution.....20 by 10 (columns 1 to 20, rows 1 to 10) 

When POV-Ray 3.70 is run on a terminal, on an unix shell, and the user hits ctrl-Z to suspend (stop) POV-Ray, rather than stopping as expected, POV-Ray just reports that it did receive the signal, as if to laugh at the user “I’m not obeying your puny stop attempts”. It

The default action (as happens if the SIGTSTP signal is not trapped) would be much better, and is usually safe also in multithread programs.
It takes actual effort to _ignore_ the TSTP signal (namely, to trap that signal), so the current behavior is definitely a dysfeature, probably an oversight by whoever programmed the signal handler.

Also, when the terminal window is resized, POV-Ray needlessly reports that it received a signal number so-and-so (the number of SIGWINCH), adding irrelevant noise to its terminal output. Both signals (SIGTSTP and SIGWINCH) should simply be excluded from the signal trapping mask. I guess there are also other signals that are needlessly captured. It would be better to capture only those signals that an action is needed for.

unixoptions.cpp has a getenv(”HOME”) that does an assignment without checking to see if getenv returns NULL.

This causes an immediate and unceremonious segfault in those situations where $HOME is not set such as in the case where povray is launched by a daemon.

Best solution might be to set the home to /tmp and print a warning message about $HOME not being set.

FileBackedPixelContainer uses a FILE* to manage the backing store and under Linux/Unix defines fseek64 to be a kind of incantation of lseek64.

Since fseek64 and fseek64 have return values that are logical opposites this causes an exception to be thrown.

Moreover since the buffer size on a FILE is quite a bit smaller than a line of pixels (in terms of bytes), mostly what’s being done in this function is a lot of sloshing of bytes that don’t do much... which is to say that the intended caching mechanism is getting a very low hit rate now that povray is working in 32×32 pixel per-thread chunks.

The cache miss problem and the volume of bytes read/written grows exponentially as the size of the image grows.

Attached is a replacement function that seems to be working well and should produce a performance increase even under Windows. I originally went with simply fixing the fseek/lseek problem but saw a 10% decrease in render time on 2048×1024-sized images when I made the cache target smaller.

Multi-textured blobs are broken with 3.7 beta 40 when used inside an intersection, as can be demonstrated by the following scene:

#default { texture { pigment { rgb 1 } } }

camera {
  right x*image_width/image_height
  location  <0,1.5,-4>
  look_at   <0,1,0>
}

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

difference { blob {
  threshold 0.6
  sphere { < 0.75,   0,    0>, 1, 1 texture { pigment { color red 1 } } }
  sphere { <-0.375,  0.65, 0>, 1, 1 texture { pigment { color green 1 } } }
  sphere { <-0.375, -0.65, 0>, 1, 1 }
} }

With POV-Ray 3.7.0 beta 40, the entire blob is rendered with the default texture.

The same problem can be seen with “difference” or “merge” instead of “intersection”.

Omitting the CSG “envelope”, using “union”, or assigning the blob to a variable first and then using it inside an intersection, will yield the expected result.

POV-Ray 3.62 renders all variants as expected.

According to initial analysis, the problem appears to be caused by the dual use of the “MULTITEXTURE_FLAG”, which is used in CSG to indicate use of the “cutaway_textures” feature, and in blobs to indicate per-element texturing. (The same flag is also used in meshes to indicate per-face or per-vertex texturing, so similar problems are to expected there.)

My proposal is to use an entirely separate flag for the “cutaway_textures” feature (the blob and mesh can safely continue to share the MULTITEXTURE_FLAG).

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 some cases it may be desirable to run POV-Ray from a batch file, without causing it to “steal the focus”.

I suggest making this dependant on whether POV-Ray is run with the /EXIT parameter.

I/O Restriction defaults are not being properly set on a fresh install of POVWIN.

See this thread for more information.

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/

The function of the “Debug_File=” .ini option has changed from 3.6 to 3.7.37a.
In 3.6, when rendering multiple frames, a debug file would be created that then appended the debug lines for each frame into the file. It was therefore able to have debug data that identified what parameters were used in which frame in case a frame did not have the desired effect.

In 3.7.37a, the debug file does not perform this function. Instead it creates a new debug file (overwriting the prior) with each new frame. Therefore the debug data is only useful for the final frame (or wherever the render was halted). This is useful for a single frame render or for identifying a fault within a series of frames (because only the last one will remain) but it is not useful for many frames that render successfully.

This problem does not cause any rendering errors or other defects. The debug file specified will only contain the debug data for the last frame rendered.

Per discussion in the forum it was unknown if this was a bug or “feature”. At this time it is causing me a problem so I am submitting the bug. No related bugs were found searching for “output” or “debug” in any status.

Operating System in use is Windows XP. I cannot test 3.7.37a in additional OSes, but it does not seem like it would be OS-specific.

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>,

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.

OpenEXR output currently writes an alpha channel when Output_Alpha=off (-UA), and does not write an alpha channel when Output_Alpha=on (+UA), i.e. doing it just the wrong way round.

Reflections in multi-layered textures are broken in 3.7 betas, as can be demonstrated with the following scene showing two reflective hemispheres on a checkered plane:

camera {
  location  <1.0, 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>
}

default {
 finish { diffuse 0 ambient 0 specular 0 }
}

// ----------------------------------------

plane {               // checkered floor
  y, -1
  texture
  {
    pigment { checker color rgb 1 color blue 1 }
    finish{ diffuse 0.8 ambient 0.1 }
  }
}

// left hemisphere
intersection {
  sphere { 0, 1 }
  plane { x, -0.002 }
  texture {
    pigment { color rgb 1 }
    finish{ reflection { 0.5 } }
  }
  texture {
    pigment { color rgbt 1 }
    finish{ reflection { 0.4 } }
  }
  texture {
    pigment { color rgbt 1 }
    finish{ reflection { 0.1 } }
  }
}

// right hemisphere
intersection {
  sphere { 0, 1 }
  plane { -x, -0.002 }
  texture {
    pigment { color rgb 1 }
    finish{ reflection { 1.0 } }
  }
}

Note that the reflection parameters of the left, multi-layered hemisphere sum up to 1.0, i.e. the same value as used in the single layer in the right hemisphere.

The first attached file (test_3.6.2.png), rendered with POV-Ray 3.6.2, shows the expected output: Both hemispheres appear to have the same reflectivity.

The second attached file (test_3.7.0.beta37a.png), rendered with POV-Ray 3.7.0.beta.37a, shows a much brighter left (multi-layered) sphere.

As it turns out, in order to get the expected result with POV-Ray 3.7.0.beta.37a, the reflectivity of each layer must be divided by 3, 2 and 1, respectively (which obviously does not sum up to 1.0):

  ...
  texture {
    pigment { color rgb 1 }
    finish{ reflection { 0.5 / 3 } }
  }
  texture {
    pigment { color rgbt 1 }
    finish{ reflection { 0.4 / 2 } }
  }
  texture {
    pigment { color rgbt 1 }
    finish{ reflection { 0.1 / 1 } }
  }
  ...

Mosaic preview display didn’t work as expected, given these command line options: +sp64 +ep16. The preview was solid colored instead of the coarse preview that you’d expect.

I’ve tested a fix to unix/disp_sdl.cpp from clipka and it appears to work.

When using “filter all VALUE” with an image_map using a 4-bit (16-color) paletted bmp image, debug builds of POV-Ray fail with an assertion.

According to code analysis, other paletted image formats with <256 palette entries are also likely to be affected; similar assertion fails can be expected when using the “filter INDEX, VALUE” feature on such files with an index exceeding the palette size. “transmit” shows the same flaws.

The included scenes\advanced\benchmark.pov (v1.02)is different then the winpov menu render\run benchmark (v2.01).

The winpov menu render\run benchmark is missing some objects, turned off in early betas?

There should be a table of contents on each page of the documentation, or at least on the very long pages. Scrolling through the entire page to figure out what topics are covered sucks.

20 library paths is a bit small given the sheer number of include files I’ve collected over the years. An increase in the number, and/or the ability to include wildcards in the search path, would be great.

Assuming there are no performance issues, it would be nice to tell Povray to select the pixels to render randomly, so that the image gets filled in gradually instead of from top to bottom and from left to right.

Also, maybe an option to tell it to render every Nth pixel.

Request an #ELSEIF statement in POV SDL.

Request #BREAK statement inside #WHILE and #FOR loops.

Many programming languages support an indeterminate number of parameters in functions/macros.

JavaScript for instance supports an “arguments” object.

Lua for instance supports the “args” object.

I would like to see that added to POV as well.

Here’s an JavaScript example:

function ArgTest(a, b){
   var i, s = "The ArgTest function expected ";
   var numargs = arguments.length;     //Get number of arguments passed.
   var expargs = ArgTest.length;       //Get number of arguments expected.
   if (expargs < 2)
      s += expargs + " argument. ";
   else
      s += expargs + " arguments. ";
   if (numargs < 2)
      s += numargs + " was passed.";
   else
      s += numargs + " were passed.";
   s += "\n\n"
   for (i =0 ; i < numargs; i++){      //Get argument contents.
   s += "  Arg " + i + " = " + arguments[i] + "\n";
   }
   return(s);                          //Return list of arguments.
}

Request a system variable to test whether a scene file has been included by another scene file.

For instance:

#if (is_included)
  camera {...}
#end

In POV SDL it can sometimes be ambiguous what exactly a macro returns. An explicit #RETURNS statement would make this unambiguous.

Currently, arrays may contain only one object type. Would be nice to eliminate this restriction and allow arrays to contain objects of different types.

Currently, many POV scenes/include files behave differently depending on the basic units used within the scene. Scaling them differently can affect things like ior and media. A master system variable that users can set to configure the scene’s units would be beneficial for sharing and collaboration purposes, so that person A’s glass interior works correctly in person B’s wine glass scene. Just like the #version system variable, it should have a default value but should be possible to explicitly override.

There are various scripts around the Net meant for approximating things like isosurfaces and parametric objects using meshes. It would probably run bit faster and be easier to use if this were supported natively within Povray. The feature would require an additional object parameter in order to toggle this behavior on/off.

It would be nice to configure an INI option to add render information like render time, date, and input file to output images.