POV-Ray

The Persistence of Vision Raytracer (POV-Ray).

This is the legacy Bug Tracking System for the POV-Ray project. Bugs listed here are being migrated to our github issue tracker. Please refer to that for new reports or updates to existing ones on this system.

IDCategoryTask TypeReported InPrioritySeverity  descSummaryStatusProgressDue In Version
313RadiosityDefinite Bug3.70 releaseLowHighradiosity.cpp pov::RadiosityFunction::BeforeTile assert...Tracked on GitHub
20%
Task Description

With 3.7.0 final, rendering attached files (for Computer Engineering college course),
which renders without issues in povray 3.6.1, fails with following error:

...
==== [Rendering...] ========================================================
povray: backend/lighting/radiosity.cpp:324: virtual void pov::RadiosityFunction::BeforeTile(int, unsigned int): Assertion `(pts >= PRETRACE_FIRST) && (pts <= PRETRACE_MAX)' failed.

Command line:

povray +K0.6500 \
+FN +Q9 +MB1 \
+W600 +H400 \
+AM1 +A0.0 +R2 \
+D +SP32 +EP4 \
+L/usr/share/povray-3.7/include \
+Imain.pov \
+Omain-0.6500.png

Using Arch Linux testing current:
Linux archmidi 3.12.0-1-ARCH #1 SMP PREEMPT Wed Nov 6 09:06:27 CET 2013 x86_64 GNU/Linux

Downstream bug report:
https://bugs.archlinux.org/task/37689

324Geometric PrimitivesDefinite Bug3.70 releaseVery LowHigh3.7 mesh2 rendering artifact, regression from 3.6Tracked on GitHub
0%
Task Description

Povray 3.7 has rendering artifact in meshes with polygons that meet at shallow angles. Please see the attached file.

The part of concern is the mesh2, which produces the partly-transparent faces of a shallow pyramid. The file result-3_6.png shows the output of povray-3.6, and the file result-3_7.png shows the output of povray-3.7. In 3.7, you can see a thin light-colored margin all around the base of the pyramid, especially thick under the top cylinder. In 3.6, this artifact is absent. For comparison purposes, I have inserted a “#version 3.6;” directive at the top of the file so that the output images are as close to each other as possible. However, the artifact is still present in 3.7 without this directive.

The attached scene file is only a small part of a much larger scene, where this artifact shows up in numerous very obvious places, where it doesn’t in 3.6. I have hunted in the documentation and online for ways to solve this problem, but haven’t found anything. Because of this, I am forced to stay with 3.6 for production use, which is quite unfortunate since I’d like to take advantage of the new features of 3.7.

70PhotonsUnimp. Feature/TODO3.70 beta 34LowHighload/save photons should be controlled via command lineTracked on GitHub
0%
Task Description

Just like radiosity load/save, the photon mapping load/save mechanism should be moved to the frontend and controlled via command-line switch, instead of being SDL-driven in the backend.

227Refactoring/CleanupUnimp. Feature/TODO3.70 RC3Very LowHighFixed Vector LimitationsTracked on GitHub
0%
Task Description

See this documentation entry for more details.

306Subsurface ScatteringDefinite Bug3.70 RC7Very LowHighfinish subsurface block before global_settings subsurfa...Tracked on GitHub
0%
3.71 release Task Description

The following scene causes a crash:

sphere {
  <0,0,0>, 1
  finish { subsurface { translucency 1.0 } }
}

global_settings {
  subsurface { }
}
328User interfaceDefinite Bug3.70 releaseVery LowMediumAscii char '=' in filenames causes command line parsing...Tracked on GitHub
0%
Task Description

The following command fails with parsing error:
povray +OqXfFbD0Vg5XjZgi5sOefkvdF_oCGrZ1ChVhrQw==.png +IqXfFbD0Vg5XjZgi5sOefkvdF_oCGrZ1ChVhrQw==.pov +W1000 +H1000

The following command succeeds:
povray +OqXfFbD0Vg5XjZgi5sOefkvdF_oCGrZ1ChVhrQw.png +IqXfFbD0Vg5XjZgi5sOefkvdF_oCGrZ1ChVhrQw.pov +W1000 +H1000

Any option that gets a filename as parameter will fail if it contains ‘=’.

It is a regression, as it worked fine with 3.6.

7RadiosityUnimp. Feature/TODO3.70 beta 32LowMediumRe-implement Radiosity render abort/continue supportTracked on GitHub
0%
Task Description

For proper render abort/continue support, radiosity cache data must be written to (or read from) disk even if the user does not explicitly opt to have a sample data file written/read. This feature has temporarily been dropped from 3.7 beta and is still pending re-implementation.

To meet high-reproducibility requirements in conjunction with SMP operation, it may be necessary to extend the 3.6 radiosity cache file format.

42OtherDefinite Bug3.70 beta 32Very LowMediumcommand line parameters are not parsed properly on UnixTracked on GitHub
0%
Task Description

POV-Ray does not follow common practice on command-line handling; for instance:

povray +i"My File"

entered on a Unix shell would be passed to POV-Ray as

povray
+iMy File

(each line representing a distinct parameter here), which POV-Ray would further dissect, interpreting it as

povray
+iMy
File

To achieve the desired effect, one would actually have to quote the string twice:

povray +i"'My File'"

which the shell would translate to

povray
+i'My File'

which POV-Ray would interpret as

povray
+iMy File

In both cases, this is obviously not what a Unix user would expect.

The further dissecting of individual command-line parameters may have had its valid roots in the peculiarities of DOS’ command-line handling, but to my knowledge all major contemporary operating systems follow a concept akin to Unix, passing a list of parameters instead of a monolithic command line, and burdening the respective command shells with the task of dissecting command lines into parameters.

Therefore I suggest to disable this anachronistic feature in favor of contemporary standards; a compiler flag might be used to allow for easy re-enabling of the feature, for compiling POV-Ray on exotic targets.

- edit -

It has been pointed out that the described behaviour differs from 3.6, so I’m promoting this to a bug and changing the title.

50Runtime errorPossible Bug3.70 beta 32Very LowMediumFrequent segfaults with photon scenesTracked on GitHub
0%
Task Description

I observe frequent segfaults with POV-Ray 3.7 betas when rendering scenes using photons:

  • Debian Linux 4.0r5 “etch” for AMD64
  • AMD Phenom X4 9650 2.3GHz, 6 GB RAM
  • POV-Ray compiled with Intel icpc 11.0

Segfaults are sporadic but frequent (occurring in roughly 50% of all photon renders).

60Geometric PrimitivesDefinite Bug3.70 beta 34Very LowMediumArtifacts using prism in CSGTracked on GitHub
0%
Future release Task Description

Using prisms in intersecion or difference CSG objects may cause artifacts in POV-Ray 3.6.2 as well as 3.7.0.beta.34, as demonstrated by the following code:


camera {
  right    -x
  up        y*image_height/image_width
  location  <-24,19,12>
  look_at   <0,0,0>
}

light_source { <100,200,100> color rgb 1 }

plane { y, -2 pigment { color rgb 1 } }


#declare KeyValue = 1.366; // pick any you like

difference {
  prism {
    linear_sweep -0.5,0.5, 4
    
    <-3,20-17>,
    <-3,KeyValue>,
    <-6,-3>,
    <-0,-5>
  }
  intersection {
    cylinder { <-7,-0.51,1>, <-7, 0.51,1>, 4.0 }
    plane { z, KeyValue }
  }
  pigment { color rgb 0.5 } 
}

Apparently the surface of the other object becomes visible when it exactly coincides with a vertex of the prism; probably there is a failure of the inside() test for such values.

75Geometric PrimitivesUnimp. Feature/TODO3.70 beta 34Very LowMediumReplace POV_MALLOC with std::vector in shape codeTracked on GitHub
30%
Future release Task Description

In the files bezier.cpp, fpmetric.cpp, fractal.cpp, hfield.cpp, isosurf.cpp, lathe.cpp, poly.cpp, polygon.cpp, prism.cpp, sor.cpp, and sphsweep.cpp the use of POV_MALLOC can be replaced by std::vector quite easily because the containing class already is a C++ class. As this is a low hanging fruit for continued code cleanup, it should be done sooner rather than later.

81Geometric PrimitivesDefinite Bug3.62Very LowMediumsphere_sweep generating artifactsTracked on GitHub
0%
Task Description

I’m running POV-Ray for (64 bit) Windows v3.62 on (64 bit) Windows Vista

This pov file:


#include "colors.inc"
#include "metals.inc"

light_source { <6, 9, -21> color White }
camera { location <0, 0, -3> look_at <0, 0, 0> }

sphere_sweep {
                cubic_spline
                6
                <-2.0, 0, 0> 0.05

                <0.000,0,0> 0.2
                <0.025,0,0> 0.2
                <0.050,0,0> 0.2
                <0.075,0,0> 0.2

                <3.0,0,0> 0.2
                pigment { color White }
}

Produces two strange artifacts: A disk at the center of the sweep, and a faint “halo” or veil which shows as 4 faint hyperbolas centered around the origin.

I have tried tweaking tolerance (for no other reason than I saw that someone else was tweaking it to solve a problem) but this does not seem to change things.

For a look at MY result when I run this, view this image:

riventree.comarchivebugdatapovrayspheresweepartifacts.jpg

Alain reports the same behavior in the latest version: “It’s still there with the latest version: 3.7 beta 35a.” This MAY move the status to “confirmed”, but I can’t do that

Someone else says that changing the scale (!) “solves” the problem by moving the disk and the halo offscreen, but that sounds like a bad idea to me.

-Jeff Evarts, first-time POVRay bug reporter

98Refactoring/CleanupUnimp. Feature/TODO3.70 beta 36DeferMediumRefactor Windows UI code for Unicode supportTracked on GitHub
50%
Future release Task Description

Windows UI code should be refactored to use _TCHAR throughout instead of char, as well as the corresponding string function macros, to head for Unicode support.

181BackendUnimp. Feature/TODO3.70 beta 40Very LowMediumUnimplemented, altered or missing features to document ...Tracked on GitHub
0%
Task Description

This is a list of unimplemented features and things to fix with respect to 3.7 vs 3.6 compatibility. They either need to be fixed in code, or failing that, to be documented prior to release.


Create_INI works differently from 3.6. Prior versions of POV-Ray would write all options to the file, even if they were not supplied by the user (non-supplied options would take the default value). Currently in 3.7, only supplied options are written, because the front-end does not send unused options to the back-end. The proper fix for this would be to have a set of defines that establish the defaults all in one place (currently we rely on hard-coded values scattered around the code), and for the Output_INI_Option() function to look up and use the default when not supplied. As this is not likely to be done before 3.7 release, we need to document it as a temporary situation.

The following messages are marked as ‘currently not supported by code’ in povmsgid.h. We need to check where this comment is correct and if so the docs need to be updated to indicate this (for items that are already documented). Some items may be re-implemented later, and some may never be:

  • kPOVAttrib_TestAbort
  • kPOVAttrib_TestAbortCount
  • kPOVAttrib_VideoMode
  • kPOVAttrib_Palette
  • kPOVAttrib_DisplayGammaType
  • kPOVAttrib_FieldRender
  • kPOVAttrib_OddField
  • kPOVAttrib_AntialiasGammaType
  • kPOVAttrib_LightBuffer
  • kPOVAttrib_VistaBuffer
  • kPOVAttrib_DrawVistas

This bug should be edited to add/remove items as time goes by.

251Parser/SDLPossible Bug3.70 RC6Very LowMediumScene / include files of >2GB size may cause problemsTracked on GitHub
0%
3.71 release Task Description

Code inspection shows that we’re still using fseek() and ftell() in various places (including text file input), which can’t handle file positions of 2GB and beyond (except on 64-bit linux machines); those calls need to be examined and (where appropriate) replaced with the fseek64() macro we’re already defining (but currently not using), and a to-be-defined ftell64() macro.

One potential (untested) error scenario would be a scene file calling a macro that is defined at the end of a > 2GB long include file.

273OtherDefinite Bug3.70 RC6Very LowMediumNo automatic backup files from inc filesTracked on GitHub
0%
Task Description

If enabled, POVray always created backups of pov and inc files once per session.
Now using 3.7 RC6 only pov file backups are created but not from inc files.

278BackendFeature Request3.70 RC7Very LowMediumImplement Lens Flare RenderingTracked on GitHub
0%
Task Description

Currently POV-Ray does not support rendering lens flare effects, however, they can be simulated using a macro (include file) by Chris Colefax.

I would like to suggest adding a feature to POV-Ray to support lens effects “natively” since

  • as far as I know the macro has been designed for POV-Ray 3.1 so with each new POV-Ray version it gets more likely that this macro does not work properly any more
  • the macro does not work when rendering with radiosity, probably because the macro creates the lens effect by using a pigment with a high ambient value (which is ignored by POV-Ray 3.7’s radiosity algorithm).

Additionally, the macro is not quite easy to employ because

  • it needs to know the exact camera parameters (location etc.) and defines an own camera itself so any important camera information has to be stored if the effect has to work as expected
  • it does not (actually cannot) take into account that objects may (partially) hide the lens effect
  • reflections and refractions (of light sources) cannot be combined with it properly - the user would have to calculate both the point where the reflected/refracted light source can be observed and the shape it then has due to distortion, and in more complex scenes such computations are nearly impossible in SDL.

I would suggest integrating such a lens flare rendering feature with the “looks like” mechanism you already have for light sources. Several parameters that can currently be set for the macro - including effect brightness and intensity, lens options and whether to create a flare at all - could be set for the light source.

Then POV-Ray could store the location and colour of each ray that finally intersected the “looks like” object of a light source and, having finished the main rendering, from that data compute a partially transparent “lens flare layer” eventually mixed into the rendered image. By this, the above mentioned problems could be avoided:

  • an object fully or partially intersecting a light source’s “looks like” object would also reduce the number of pixels used to create a flare - and therefore reduce that flare until fully hiding it
  • the same goes for reflected and/or refracted versions of the “looks like” object
  • the camera’s location and other properties would be used automatically
  • and finally, as a feature supported by POV-Ray itself, there would be neither compatibility issues nor problems like the effect not fitting together with radiosity.

Do not get me wrong, I would not expect POV-Ray to really calculate intersections that naturally happen in a camera lens, causing lens flares. Effects looking appropriate can actually be created just in 2D space (as some graphics programs do support) so the work to be done would, as far as I have any overview, be:

  • storing, as mentioned above, the relevant data for pixels showing “looks like” objects
  • calculating a lens flare from that data after the render has finished
  • overlaying the rendered image with the newly created lens effect.
296Geometric PrimitivesDefinite Bug3.70 RC7DeferMediummax gradient computation is not thread safe (isosurface...Tracked on GitHub
0%
3.71 release Task Description

It appears as a side effect of investigation of #294: the code in isosurf.cpp, inside
bool IsoSurface::Function_Find_Root_R(ISO_ThreadData& itd, const ISO_Pair* EP1, const ISO_Pair* EP2, DBL dt, DBL t21, DBL len, DBL& maxg)

	if(gradient < temp)
		gradient = temp;

is not thread-safe (The code is used at render time, there is a data race between < and = operation, as gradient is stored in the global object and accessed in write mode by the cited code)

It is only important if the gradient is initially undervaluated (otherwise, all is fine, no write-access)

26Geometric PrimitivesDefinite Bug3.61Very LowLowArtifacts rendering a cloth which has two-side texturesTracked on GitHub
0%
Future release Task Description

Dear PovRay maintainers and developers, congratulations for your great RayTracer!

We think that we have found a bug while we were rendering a piece of cloth.

In this piece of cloth were defined two textures, one for one side and one for the another side:

  texture { mesh_tex0_0 }
  interior_texture { mesh_tex0_1 }
  • Please: Look at line 77414 of the attached file “test.pov” to see

these definitions in their original context.

We have found some artifacts in the final rendering, in concrete near some wrinkles,
please, look at the attached file “render_artifacts.tga”, I have painted a big green arrow
near the artifacts, maybe you’ll need to do a zoom to see them more accurately.

They are as though the texture of the other side was painted in the incorrect side.

Fortunately, we have a patch to fix this bug (thanks to Denis Steinemann, he made the
implementation for PovRay 3.5, so I have adapted these changes to release 3.6.1)

Although we have found this bug in the Windows and Linux 3.6.1 releases,
the patch was generated in Linux (using the source code release of “povray-3.6.1”).

To apply this patch, inside the parent folder of the directory “povray-3.6.1” execute:

            patch -p0 < other_side_artifacts.patch

And the “povray-3.6.1” will be patched and you will get a console output like this:

 patching file povray-3.6.1/source/lighting.cpp
 patching file povray-3.6.1/source/mesh.cpp
 patching file povray-3.6.1/source/render.cpp

We don’t know if this “hack” is enough smart to apply in the next release,
but we think that it fixes the bug (the artifacts dissapear).

Best regards and thank you very much for your great RayTracer!

311User interfacePossible Bug3.70 releaseVery LowLowElepsed time error on very long rendersTracked on GitHub
0%
3.71 release Task Description

On a very long render, around day 24, the elapsed time display becomes incorrect, showing 4294967272d 4294967272h 4294967272m 4294967272s.

Found on Windows 7 64 bits and reproduced on Windows 7 32 bits.
NOT reported on other platforms.

319Texture/Material/FinishFeature Request3.70 releaseVery LowLowAdd interior to #default directiveTracked on GitHub
0%
Task Description

When working with predefined materials, it would be useful to have something like:

#if (!Use_photons)
  #default { interior { caustics 1 } }
#end

#include "my_predefined_materials.inc"

Default medias or IORs could also be useful.

321OtherDefinite Bug3.70 releaseVery LowLowbounding threshold inconsistencyTracked on GitHub
90%
Task Description

User reported documentation inconsistency. Investigation led to the discovery of a bug in the setting of the current default value.

~source/frontend/renderfrontend.cpp reports the value “3” while ~source/backend/scene/scene.cpp sets a default value of “1”

Before for addressing this issue, are there any thoughts as to what the default value should be?

326OtherDefinite Bug3.70 releaseVery LowLowrestricted setting ignored in 3.7Tracked on GitHub
0%
Task Description

Due to a typo in the conf file parser (introduced, I think, in refactoring after 3.6), the restricted setting is ignored, and access checks aren’t performed.

Fixing this reveals some other issues:

  • %INSTALLDIR%/../../etc is incompletely canonicalized to /usr/local/share/../etc, not /usr/local/etc
  • read+write paths are added to the read list only, so writing is impossible

See attached patch.

Relatedly, I think it would be nice to add a new replacement token %CONFDIR% instead of %INSTALLDIR%/../../etc.

Also, there’s a realpath function that could simplify path handling, though I’m not sure if it’s available on all platforms.

327Parser/SDLFeature Request3.70 releaseVery LowLowSupport for non-ASCII characters in filename stringsTracked on GitHub
0%
Task Description

pov 3.7 Can not identify the Chinese.I give the texture map filename in chinese,it turns out parse error.

333User interfaceFeature Request3.70 releaseVery LowLowMake text in "about" alt+b dialog selectable with the m...Tracked on GitHub
0%
Task Description

When you press alt+b or access the “about” dialog in the Help menu it displays some text including software version number and list of contributors.

It would be nice to be able to select and copy this text using this mouse. Sometimes in the newsgroup I have to tell people what version of POVray I am using, and typing the version number can be a pain.

334Texture/Material/FinishFeature Request3.70 releaseVery LowLowHLS colorsTracked on GitHub
0%
Task Description

It would be nice to be able to specify colors in HLS as well as RGB.

Currently, you can use a macor to convert individual colors. But this does not work in color_maps where you want smooth gradations/interpolations between two or several colors.

335Parser/SDLPossible Bug3.70 releaseVery LowLowmacro works in variable but not in arrayTracked on GitHub
0%
Task Description

This doesn’t work:

#declare pavement_object = array[2]
{

object {trash_can_macro()	scale 3/4			translate -x * 1/2},
object {potted_plant_macro(_CT_rand2)	scale 3/4	scale 3/2	translate -x * 1/2}

}

This does work:

#declare trash_can_object = object {trash_can_macro()};
#declare potted_plant_object = object {potted_plant_macro(_CT_rand2)};
#declare pavement_object = array[2]
{

object {trash_can_object	scale 3/4			translate -x * 1/2},
object {potted_plant_object	scale 3/4	scale 3/2	translate -x * 1/2}

}

Logically, I cannot see a reason for this to be so.

44RadiosityFeature RequestAllVery LowLowImprove Normals Handling in RadiosityTracked on GitHub
0%
Future release Task Description

Currently, radiosity does not make use of the fact that pertubed normals would theoretically just require a different weighting of already-sampled rays, leading to the following issues:

  • Honoring normal pertubations in radiosity leads to an increased number of samples, slowing down sample cache lookup.
  • The increased number of samples is generated from a proportionally higher number of sample rays, slowing down pretrace even further.
  • Low-amplitude pertubations tend to be smoothed out; “reviving” these is only possible by increasing the general sample density.
  • Handling of multi-layered textures with different normal pertubations is currently poorly implemented.

As a solution, I propose to store for each radiosity sample not only the resulting illumination for a perfectly unpertubed normal, but from the same set of sample rays also compute the illumination for an additional set of about a dozen standardized pertubed-normal directions, and interpolate among these when computing the radiosity-based illumination for a particular point that has a pertubed normal.

For backwards compatibility, this method of dealing with pertubed normals in radiosity might be activated by a different value for the “normal” statement in the radiosity block, say, “normal 2”.

243Geometric PrimitivesUnimp. Feature/TODOAllDeferLowSphere sweep behaves wrong when scaledTracked on GitHub
0%
Future release Task Description

The sphere_sweep renders well when specified directly, but when it is scaled, its bounding box is calculated incorrectly, which clips the object so it almost disappears.

The effect is present for all three types of splines.

I’m attaching a test scene and the rendering result. The saving of the object with #declare has no effect, I just wanted to show both transformed and untransformed version.

I don’t think this issue is related to other artifacts occuring with sphere_sweep, as it is obviously an issue of the internal bounding box.

245OtherFeature RequestAllDeferLowPOVMS message queue can fill up with GB of data for ver...Tracked on GitHub
0%
Future release Task Description

With very fast renders and very large output files, the message queue can fill up because the producers are not limited by IO, while the consumer performance is limited by disk IO. Consequently, the message queue can fill up to exhaust all available memory. The solution is to build in some better control of pending output data in the message queue on the producer side. This will also pave the way for message communication over slow links (i.e. a network).

4Subsurface ScatteringUnimp. Feature/TODO3.70 beta 32Very LowLowIntegrate Subsurface Scattering with standard lighting ...Tracked on GitHub
90%
Future release Task Description

Subsurface Scattering still uses its own rudimentary code to compute illumination from classic light sources; this must be changed to use the standard light source & shadow handling code, to add support for non-trivial light sources (e.g. spotlights, cylindrical lights, area lights), partially-transparent shadowing objects etc.

6Subsurface ScatteringUnimp. Feature/TODO3.70 beta 32DeferLowIntegrate Subsurface Scattering with PhotonsTracked on GitHub
0%
Future release Task Description

Subsurface scattering must be made photon-aware.

8RadiosityUnimp. Feature/TODO3.70 beta 32DeferLowImprove Radiosity "Cross-Talk" Rejection in CornersTracked on GitHub
0%
Future release Task Description

Near concave edges, radiosity samples may be re-used at a longer distance away from the edge than towards the edge; there is code in place to ensure this, but it only works properly where two surfaces meet roughly rectangularly, while failing near the junction of three surfaces or non-rectangular edges, potentially causing “cross-talk”.

It should be investigated how the algorithm can be improved or replaced to better cope with non-trivial geometry.

25AnimationDefinite Bug3.70 beta 32DeferLowPause sometimes fails when rendering animationTracked on GitHub
90%
Task Description

There is an issue where the pause button in POVWIN will sometimes not work during an animation (primarily where the frame rate is high), and furthermore, POVWIN can then get into a state where it’s not possible to use the pause until it is re-started.

Newsgroup report.

27OtherFeature Request3.70 beta 32Very LowLowAdd texture support to background statementTracked on GitHub
0%
Future release Task Description

Adding full texture statement support to the background statement (with a scale of 1/1) aligned with the image_map direction of an image would allow i.e. specifying an image as background easily.

28FrontendFeature Request3.70 beta 32Very LowLow#debug message not displayed.Tracked on GitHub
0%
Future release Task Description

The #debug message stream is only being flushed when it hits a newline character,
instead of after each #debug statement. This means that some final strings don’t show up.

#debug "This line prints,\n but this line doesn't."
41OtherFeature Request3.70 beta 32Very LowLowimprove command-line parsing error messagesTracked on GitHub
0%
Task Description

POV-Ray 3.6, upon encountering problems when parsing command line and/or .ini file options, would quote the offending option in the error message.

POV-Ray 3.7 currently just reports that there is some problem with the command line, without providing any details. I suggest changing this, as the information may be helpful at times.

47PreviewPossible Bug3.70 beta 32Very LowLowRender Preveiw window can become disabledTracked on GitHub
0%
Task Description

If a render is continued with the +c option and the render had completed, the render preview window will disappear and the show/hide render window button will be grayed. Even after the scene is modified and the command line options have been changed, the show/hide button will still be grayed.

Opening or changing to another scene and rendering will not restore the button, nor will rendering with +d. However, if a trace is started using -d, halted, then continued using +d (or allowed to finish completely with -d and a new one is started using +d), then the preview window is restored.

This behavior is different from 3.6.1, which correctly always showed the preview window (since +d is default) unless -d was specified.

58Parser/SDLUnimp. Feature/TODO3.70 beta 32DeferLowallow SDL code to detect optional featuresTracked on GitHub
0%
Task Description

Some features are optional in custom builds of POV-Ray (I’m thinking about OpenEXR in particular); it would be nice to have a syntax for an SDL script to check for support of such features, so it may take some fallback action if the feature is not supported.

85OtherFeature RequestNot applicableDeferLowAspect ratio issuesTracked on GitHub
0%
Future release Task Description

Background

When rendering an image, there are actually three aspect ratios involved:

1) The aspect ratio of the camera, set with the up and right vectors.

2) The aspect ratio of the rendered image, set with the +W and +H parameters.

3) The aspect ratio of the pixels in the intended target medium. While this is very often 1:1, it’s definitely not always so (anamorphic images are common in some media, such as DVDs).

The aspect ratio of the camera does not (and arguably should not, although some people might disagree) define the aspect ratio of the image resolution, but the aspect ratio of the image as shown on the final medium. In other words, it defines how the image should be displayed, not what the resolution of the image should be.

This of course means that the aspect ratio of the target medium pixels has to be taken into account when specifying the image resolution. If the target medium pixels are not 1:1 (eg. when rendering for a medium with non-square pixels, or when rendering an anamorphic image eg. for a DVD), the proper resolution has to be specified so that the aspect ratio of the displayed image remains the same as the one specified in the camera block.

This isn’t generally a problem. It usually goes like “my screen is physically 4:3, so I design my scene for that aspect ratio, but the resolution of my screen is mxn which is not 4:3, but that doesn’t matter; I just render with +Wm +Hn and I get a correct image for my screen”.

However, problems start when someone renders an image using an image aspect ratio / pixel aspect ratio combination which does not match the camera aspect ratio. By far the most common situation is rendering a scene with a 4:3 camera for a screen with square pixels but with a non-4:3 resolution (most typically 16:9 or 16:10 nowadays). The image will be horizontally
stretched.

In a few cases the effect is the reverse: The scene (and thus the camera) has been designed for some less-typical aspect ratio, eg. a cinematic 2.4:1 aspect ratio, but then someone renders the image with a 4:3 resolution. The resulting image will be horizontally squeezed.

In a few cases this is actually the correct and desired behavior, ie. when you are really rendering the image in an anamorphic format (eg. for a DVD). However, often it’s an inadverted mistake.

Some people argue that this default behavior should be changed. However, there are also good arguments why it should not be changed. Some argue that POV-Ray should have more features (at the SDL level, at the command-line level or both) to control this behavior.

There are several possible situations, which is why this issue is so complicated. These situations may include:

- The scene author doesn’t really care what aspect ratio is used to render the image, even if it means that additional parts of the scenery become visible or parts are cropped away when using a different aspect ratio than what he used.

In this case the choice of camera aspect ratio should be up to the person who renders the image, and thus selectable on the command-line. However, he should have an easy choice of how changing the aspect ratio affects the image: Should it extend the viewing range, or should it crop part of it, compared to the original?

And this, of course, while still making it possible to render for an anamorphic format.

- The author wants to support different aspect ratios, but he wants to control precisely how it affects the composition of the image. Maybe he never wants anything cropped away within certain limits, but instead the image should always be extended in whichever direction is necessary due to the aspect ratio. Or maybe he wants to allow cropping the image, but only up to a certain point. Or whatever.

In this case the choice of camera aspect ratio should be up to the author, and thus selectable in the scene file, while still allowing some changes from the command-line.

- The author designed his scene for a precise aspect ratio and nothing else, and doesn’t want the image to be rendered in any other aspect ratio. Maybe he used some very peculiar aspect ratio (eg. something like 1:2, ie. twice as tall as wide) for artistic composition reasons, and wants the image rendered with that aspect ratio, period.

Perhaps the author should be able to completely forbid the change of camera aspect ratio in the command-line.

Of course anamorphic rendering should still be supported for targets with a different pixel aspect ratio.

Possible solution

This solution does not necessarily address all the problems described above perfectly, but could be a good starting point for more ideas:

Add a way to specify in the camera block minimum and maximum limits for the horizontal and vertical viewing angles (and if any of them is unspecified, it’s unlimited). Of course for this to be useful in any way, there should also be a way to change the camera and pixel aspect ratios from the command line.

The idea with this is that the author of the scene can use these angle limits to define a rectangular “protected zone” at the center of the view, using the minimum angle limits. In other words, no matter how the camera aspect ratio is modified, the horizontal and/or vertical viewing angles will never get smaller than these minimum angles. This ensures that the image will never be cropped beyond a certain limit, only extended either horizontally or vertically to ensure that the “protected zone” always remains fully visible regardless of what aspect ratio is used.

The maximum angles can be used for the reverse: They ensure that no scenery beyond a certain point will ever become visible, no matter what aspect ratio is used. This can be used to make sure that unmodelled parts of the scene never come into view. Thus the image will always be cropped to ensure this, depending on the aspect ratio.

I’m not completely sure what should be done if both minimum and maximum angles are specified, and the user specifies an aspect ratio which would break these limits. An error message could be a possibility. At least it would be a way for the author to make sure his scene is never rendered using an aspect ratio he doesn’t want. He can use these angle limits to give some leeway how much the aspect ratio can change, to an extent, or he could even force a specific aspect ratio and nothing else (by specifying that both the minimum and maximum angles are the same).

So in short:

- Add a “minimum/maximum horizontal/vertical angles” feature to the camera block. These can be used to define a “protected zone” in the image which must not be breached by command-line options.

- Add a command-line syntax to change the camera aspect ratio (which automatically obeys the “protected zone” settings). Could perhaps give an error message if the command-line options break the limits in the scene camera.

- Add a command-line syntax to specify a pixel aspect ratio other than 1:1. This can be used to render anamorphic versions of the image on purpose (iow. not by mistake).

This can probably be made backwards-compatible in that if none of these new features are used, the behavior could be the same as currently (or at least similar).

96Texture/Material/FinishFeature RequestNot applicableVery LowLowUser-defined warpsTracked on GitHub
0%
Future release Task Description

User-defined warps would be nice to have, something along the lines of:

warp {
  function { MyFnX(x,y,z) } // function to compute pattern-space x-coordinate from object-space <x,y,z> coordinate
  function { MyFnY(x,y,z) } // ditto for pattern-space y coordinate
  function { MyFnZ(x,y,z) } // ditto for pattern-space z coordinate
}

// a displacement warp:
warp {
  function { x + MyFnX(x,y,z) }
  function { y + MyFnY(x,y,z) }
  function { z + MyFnZ(x,y,z) }
}
248Parser/SDLFeature RequestNot applicableVery LowLowImplement mechanism to compute direction of a splineTracked on GitHub
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Future release Task Description

The SDL currently provides no way to compute the exact direction of a spline at a given location, even though mathematically this is a piece of cake: The first-order derivative of any spline section gives you the “speed” as a vector function, and is trivial to compute for polynomial splines (which are behind all spline types that POV-Ray supports); the normalized “speed” vector, in turn, gives the “pure” direction.

For exact direction/speed computations, I propose to extend the SDL invocation syntax as follows to allow for evaluating a spline’s derivative:

    SPLINE_INVOCATION:
        SPLINE_IDENTIFIER ( FLOAT [, SPLINE_TYPE] [, FLOAT] )

or

    SPLINE_INVOCATION:
        SPLINE_IDENTIFIER ( FLOAT [, FLOAT] [, SPLINE_TYPE] )

where the second FLOAT will specify the order of derivative to evaluate (defaulting to 0). In order to compute the position, direction, and acceleration of an object traveling along a certain spline, one could then for instance use:

    #declare S        = spline { ... }
    #declare Pos      = S(Time);
    #declare VSpeed   = S(Time,1);
    #declare VAccel   = S(Time,2);
    #declare Dir      = vnormalize(VSpeed);
    #declare Speed    = vlength(VSpeed);
    #declare AccelDir = vnormalize(VAccel);
    #declare GForce   = vlength(VAccel) / 9.81;

Alternatively, a mechanism may be devised to create a spline representing another spline’s derivative; however, it would be debatable whether the syntax should be parameter-like (being an added information that could be overridden again when creating other splines from such a derived spline), or operation-like (converting the spline), and in the latter case how it should affect spline type (and consequently control points); so the spline invocation parameter approach might be more straightforward, with less potential surprises for the user.

282Image formatFeature RequestNot applicableDeferLowUnrendered region should be transparent, not blackTracked on GitHub
0%
Future release Task Description

When rendering only a region of a file, using the command-line options +sc/+sr/+ec/+er, the area of the image that is excluded comes out as black in the final PNG.

Expected behaviour is for it to be transparent.

65Parser/SDLFeature Request3.70 beta 34Very LowLowAdd support for vectors with functionsTracked on GitHub
0%
Future release Task Description

Being able to have functions operate on vectors would be pretty nice to have.

71User interfaceUnimp. Feature/TODO3.70 beta 34Very LowLowraise warning when command line option has no effectTracked on GitHub
0%
Task Description

Warnings should be raised when a command line option has no effect,
for example...

pvengine +am

is legal, but without the number after it, it has no effect.

pvengine +am7

should be an error, and also raises no warnings.

91Texture/Material/FinishFeature Request3.70 beta 36DeferLowSlope pattern applied to object is not transformed afte...Tracked on GitHub
0%
Future release Task Description

There is an big issue with the slope pattern: when the object it is applied to is instanced (again) with a transformation (in particular a rotation, as a translation would not impact.. but a shear might), the colours of the surfaces are changed.

  
object { p translate -5*x }
object { p rotate 220*y+20*x    translate 3*x }       

Nobody would expect the object to be different in appearance.
If slope {} is replaced with wood, all is fine. (as for others textures, i guess)

IMHO, the slope vector need to be adjusted for the later transformation(s) (so as to compensate the issue of using the Perturbed Normal vector).

This should not impact the AOI/FACING (experimental) patterns, as AOI definition is pretty clear about duplicating & transform if you think about it a bit, as well as FACING: for these two, it is expected to either use the ray(current point of view) or a fixed 3D point as reference. At the limit, discussion about moving the 3D point of FACING might also be opened to interpretation.

AOI/FACING are in task #19

79Source codeFeature Request3.70 beta 35aVery LowLowFull-Featured Test-Scene to check the correctness of po...Tracked on GitHub
0%
Future release Task Description

Hi,

it would be nice if there exists a test scene (not a benchmark) which has a high coverage of povray source and can be used as correctness validation of povray. It schould be produce an image which can be compared to a golden reference image.

It may be also possible to create a regression test suite which does automatic comparision of the render results.

106DistributionUnimp. Feature/TODO3.70 beta 37Very LowLowUpdate sample scenes and include files for POV-Ray 3.7 ...Tracked on GitHub
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Task Description

Most sample scenes and include files were designed at times when POV-Ray did not to any proper gamma handling, or still used the inferior 3.6 “assumed_gamma” mechanism.

All the scenes and include files should be reviewed, and updated to fit the new 3.7 gamma model.

The primary task will probably be gamma-adjusting literal color values and ambient parameters; I suggest using macros (which ideally should be defined in an include file) to be set according to the #version statement, so the scene/include file could be kept compatible with older versions.

108Parser/SDLFeature Request3.70 beta 37Very LowLowmotion_blur feature similar to Megapov versionTracked on GitHub
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Future release Task Description

motion_blur which is a simple and effective feature to use in Megapov to simulate motion blur of, e.g. bird wings, propellers or running animals, would be a neat addition to version 3.7 and later.

In Megapov, the feature requires a line of code in the global_settings{} e.g.: motion_blur 10, 2
and a declaration for the moving object. e.g.:

motion_blur {
  type 0
  object{MyObject  material{MyMaterial rotate x*clock*2}}
  rotate x*clock*10
}

type represents several types of pre-defined motions.

Thanks,

Thomas

115Texture/Material/FinishFeature Request3.70 beta 37aVery LowLowMore cutaway_texturesTracked on GitHub
0%
Future release Task Description

Think this is still a problem. See the attached scene file. Find the WindowFrameSegment declaration for more info. The scene as-is shows the problem (SOME portions of the difference inherit the color of the room) the window opening is scaled larger to show that they AREN’T touching. The problem goes away when (in WindowFrameSegment) the 1st occurrence of the applied texture is commented out and the 2nd occurrence is uncommented, and cutaway_textures is commented out.

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