POV-Ray

#macro A()
    #local f = function { x }
#end

#local f = 1;
A()

This gives:

File 'bug.pov' line 2: Parse Error: Attempted to redefine float identifier as
 function identifier.

The problem is that this makes using functions in library macros difficult. Basically, they must have a globally unique name that’s not used in any of the macros or files that call the macros. #undef doesn’t really help, because it destroys the identifier in the calling scope.

For example, one of the macros in the standard include files names a function “fn”, so this doesn’t work:

#include "transforms.inc"

#local fn = 42; // fnord?
#local fn_pos = vtransform(x, transform { rotate 30*y } );

The reason for this restriction is explained in Parse_RValue in source/backend/parser/parse.cpp:

    // Do NOT allow to redefine functions! [trf]
    //   #declare foo = function(x) { x }
    //   #declare foo = function(x) { foo(x) } // Error!
    // Reason: Code like this would be unreadable but possible. Is it
    // a recursive function or not? - It is not recursive because the
    // foo in the second line refers to the first function, which is
    // not logical. Further, recursion is not supported in POV-Ray 3.5
    // anyway. However, allowing such code now would cause problems
    // implementing recursive functions after POV-Ray 3.5!

In this case the restriction is applied too broadly: it should be safe to redefine anything other than a function to a function and still avoid it looking like recursion. In fact, there’s a restriction in Parse_Declare specifically to prevent redefining functions.

I tried to use 3.7 RC3. This was my first time with 3.7.

I got source, configured and compiled it and installed into Debian with checkinstall. And then I tried to use it. First run was with -benchmark (it took about 9 minutes, ok). Then I tried very simple scene:

rekcahx@oah:~/pov$ povray +Iaa.pov
povray: This is a RELEASE CANDIDATE version of POV-Ray. General distribution is discouraged.
Failed to parse command-line option

I tried to debug with strace:

rekcahx@oah:~/pov$ strace -o debug.strace povray +Iaa.pov
povray: This is a RELEASE CANDIDATE version of POV-Ray. General distribution is discouraged.
Persistence of Vision™ Ray Tracer Version 3.7.0.RC3 (g++ 4.6.1 @
x86_64-unknown-linux-gnu)
This is a release candidate of POV-Ray version 3.7.0.
General distribution is strongly discouraged.

POV-Ray is based on DKBTrace 2.12 by David K. Buck & Aaron A. Collins
Copyright 1991-2003 Persistence of Vision Team
Copyright 2003-2011 Persistence of Vision Raytracer Pty. Ltd.

Primary POV-Ray 3.7 Architects/Developers: (Alphabetically)

Chris Cason         Thorsten Froehlich  Christoph Lipka   

With Assistance From: (Alphabetically)

Nicolas Calimet     James Holsenback    Christoph Hormann   Nathan Kopp       
Juha Nieminen     

Past Contributors: (Alphabetically)

Steve Anger         Eric Barish         Dieter Bayer        David K. Buck     
Nicolas Calimet     Chris Cason         Aaron A. Collins    Chris Dailey      
Steve Demlow        Andreas Dilger      Alexander Enzmann   Dan Farmer        
Thorsten Froehlich  Mark Gordon         James Holsenback    Christoph Hormann 
Mike Hough          Chris Huff          Kari Kivisalo       Nathan Kopp       
Lutz Kretzschmar    Christoph Lipka     Jochen Lippert      Pascal Massimino  
Jim McElhiney       Douglas Muir        Juha Nieminen       Ron Parker        
Bill Pulver         Eduard Schwan       Wlodzimierz Skiba   Robert Skinner    
Yvo Smellenbergh    Zsolt Szalavari     Scott Taylor        Massimo Valentini 
Timothy Wegner      Drew Wells          Chris Young       

Other contributors are listed in the documentation.

Support libraries used by POV-Ray:

ZLib 1.2.3.4, Copyright 1995-1998 Jean-loup Gailly and Mark Adler
LibPNG 1.2.44, Copyright 1998-2002 Glenn Randers-Pehrson
LibJPEG 62, Copyright 1998 Thomas G. Lane
LibTIFF 3.9.5, Copyright 1988-1997 Sam Leffler, 1991-1997 SGI
Boost 1.46, http://www.boost.org/
OpenEXR, Copyright (c) 2004-2007, Industrial Light & Magic.

Parser Options

Input file: aa.pov
Remove bounds........On 
Split unions.........Off
Library paths:
  /usr/share/povray
  /usr/share/povray/ini
  /usr/share/povray/include
Clock value:    0.000  (Animation off)

Image Output Options

Image resolution.....320 by 240 (rows 1 to 240, columns 1 to 320).
Output file..........aa.png, 24 bpp PNG
Dithering............Off
Graphic display......Off
Mosaic preview.......Off
Continued trace......Off

Information Output Options

All Streams to console..........On 
Debug Stream to console.........On 
Fatal Stream to console.........On 
Render Stream to console........On 
Statistics Stream to console....On 
Warning Stream to console.......On 

[Parsing...]

Parse Time:       0 hours  0 minutes  0 seconds (0.001 seconds)
            using 1 thread(s) with 0.000 CPU-seconds total
Bounding Time:    0 hours  0 minutes  0 seconds (0.000 seconds)
            using 1 thread(s) with 0.000 CPU-seconds total

Quality:  9
Bounding boxes.......On   Bounding threshold: 3
Antialiasing.........Off

[Rendering...]

Photon Time:      No photons
Radiosity Time:   No radiosity
Trace Time:       0 hours  0 minutes  0 seconds (0.016 seconds)
            using 4 thread(s) with 0.036 CPU-seconds total

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++ 4.6.1
Compiler flags:      -pipe -Wno-multichar -Wno-write-strings -fno-enforce-eh-specs -s -O3 -ffast-math -march=native -pthread

Thin tori exhibit artifacts in 3.7.0 RC3 when the camera is placed inside the torus close to its “center plane”, as can be demonstrated with the following scene:

camera {
  location  <0.0, 0.0, -0.5>
  direction 1.5*z
  right     x*image_width/image_height
  look_at   <0.0, 0.0,  0.0>
  angle 1
}

light_source { <-30, 30, -30> color rgb 1 }

torus {
  1, 0.001
  texture { pigment { color red 1 } }
}

It would be nice when quitting a render if the remaining space were filled with empty pixels. That way the partial render will still be viewable in all image apps.

For the next beta version, could you please create a new desktop icon? I keep clicking on the wrong version.

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.

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

I tried to render a candle’s flame (an object with interior made of emission media) against an Alpha background. In 3.6, the “flame” appears as a bright object against the alpha background; but in 3.7, the flame disappears against the alpha (as the attached scene will make clear, the “flame” is still visible against opaque background objects). I used the settings “Output_Alpha=true Output_File_Type=N”.

If there is another (better?) way to achieve a similar effect, I am open to using a work-around.

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

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

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.

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).

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)

‘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.

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).

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.

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

See this thread for more information.

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.

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/

Windows allows you to associate programs with file extensions using the “Open with” file manager right-click menu extension.

I’m running Windows 7 64bit, and installed the 64 bit versions of 3.6.2 and the beta appropriately.

A couple of problems that I haven’t tested very thoroughly:

1. If you have both POV 3.6.2 and the beta installed at the same time, you can no longer using this dialog change the association to the beta once it has been created for 3.6.2. There’s no error or anything; it just opens the file inside 3.6.2 instead. Maybe because both versions appear as “POV-Ray for Windows” to this dialog? Would adding the version number to the name fix things? Anything I can do on my end of things to resolve this?

2. In POV-Ray 3.6.2, I can use this dialog to open *.inc, *.txt and other files in POV-Ray, but only if POV-Ray isn’t already running. If POV-Ray is already running I get an “Only /EDIT and /RENDER may be passed to previous instance” error. Files with the *.pov extension open properly regardless, without any error. I am unable to test this in the beta at the moment due to the first problem unfortunately. Could someone please test this with the beta and confirm whether the behavior also exists?

3. With the POV-Ray 3.7 beta, entering the following command in the command prompt results in the same error:

   "C:\Program Files\POV-Ray for Windows v3.7\bin\pvengine64.exe" "D:\Working\Povray\GearHead\LoadingScreen\btr_maanji.pov"

If I change it to the following it works however:

   "C:\Program Files\POV-Ray for Windows v3.7\bin\pvengine64.exe" /EDIT "D:\Working\Povray\GearHead\LoadingScreen\btr_maanji.pov"

Is this error/behavior really necessary? Would it be OK to instead change the behavior when the /EDIT flag is omitted in the
command-line such that the file is opened in the editor by default, without throwing an error?

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.

Request an #ELSEIF statement in POV SDL.

There already exist atan, atan2 and atan2d functions, why not atand?