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306 | Subsurface Scattering | Definite Bug | 3.70 RC7 | Very Low | High | finish subsurface block before global_settings subsurfa... | Tracked on GitHub | |
3.71 release |
Task Description
The following scene causes a crash:
sphere {
<0,0,0>, 1
finish { subsurface { translucency 1.0 } }
}
global_settings {
subsurface { }
}
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313 | Radiosity | Definite Bug | 3.70 release | Low | High | radiosity.cpp pov::RadiosityFunction::BeforeTile assert... | Tracked on GitHub | |
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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
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60 | Geometric Primitives | Definite Bug | 3.70 beta 34 | Very Low | Medium | Artifacts using prism in CSG | Tracked on GitHub | |
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.
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26 | Geometric Primitives | Definite Bug | 3.61 | Very Low | Low | Artifacts rendering a cloth which has two-side textures | Tracked on GitHub | |
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 }
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!
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196 | Subsurface Scattering | Definite Bug | 3.70 RC3 | Very Low | Low | More SSLT Caveats | Tracked on GitHub | |
Future release |
Task Description
when a prism is differenced with a primitive (cylinder in this case) if sslt is used it causes a seq fault. Reference distribution file logo.inc and the Povray_Logo_Prism definition.
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301 | Other | Definite Bug | 3.70 RC7 | Very Low | Low | Fallback to default image size causes wrong values to b... | Tracked on GitHub | |
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Task Description
When resolution is not specified (neither via POVRAY.INI nor via QUICKRES.INI nor via command line or custom .ini file), random values are displayed for image resolution in the Image Output Options message output. (The actual render will be performed at the default size of 160×120 pixels though.)
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44 | Radiosity | Feature Request | All | Very Low | Low | Improve Normals Handling in Radiosity | Tracked on GitHub | |
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”.
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96 | Texture/Material/Finish | Feature Request | Not applicable | Very Low | Low | User-defined warps | Tracked on GitHub | |
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) }
}
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248 | Parser/SDL | Feature Request | Not applicable | Very Low | Low | Implement mechanism to compute direction of a spline | Tracked on GitHub | |
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.
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327 | Parser/SDL | Feature Request | 3.70 release | Very Low | Low | Support for non-ASCII characters in filename strings | Tracked on GitHub | |
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Task Description
pov 3.7 Can not identify the Chinese.I give the texture map filename in chinese,it turns out parse error.
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272 | Other | Feature Request | 3.70 RC6 | Defer | Very Low | Minor change, significant speedup in cubic polynomial s... | Tracked on GitHub | |
3.71 release |
Task Description
While familiarizing myself with the code, I found some small changes in the solve_cubic function that lead to a significant speedup.
In my experience, “pow” is by far the slowest function in math.h and replacing it with simpler functions usually makes a tremendous impact on the speed (it’s an order of magnitude slower than sqrt/exp/cbrt/log).
solve_cubic has a “pow” function that can be replaced by cbrt (cubic root), which is standard in ISO-C99 and should be available on all systems. Separate benchmarks of solve_cubic function show this change almost doubles the speed and does not lower the accuracy. As solve_cubic is part of the solution of quartic equation, this improves the speed for many primitives. Testing with a scene containing many torus intersection tests (attached below) I still observed almost 10% speedup (Intel, 4 threads, 2 hyperthreaded cores, antialiasing on, 600×600: from 91 to 84 seconds). And this is for a torus, where a lot of time is spent in the solve_quartic and cubic solver is only called once! Similar speedup should be expected for prism, ovus, sor and blob.
I do believe the cubic solver can be done without trigonometry, but that would mean changing the algorithm, introducing new bugs and requiring a lot of testing. However, the trigonometric evaluation can still be simplified (3% speedup in full torus benchmark).
These changes don’t affect the algorithm at all, they are mathematically identical to the existing code, so the changes can be applied immediately. I also included other changes just as suggestions. Every change is commented and marked with [SC 2.2013].
This sadly does not speedup the sturm solver, which uses bisection and regula-falsi and looks very optimized already.
The test scene I used has a lot of torus intersections from various directions (shadow rays, main rays, transmitted rays).
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183 | Texture/Material/Finish | Possible Bug | 3.70 beta 40 | Very Low | Low | cutaway_textures broken with child unions | Tracked on GitHub | |
Future release |
Task Description
When using cutaway_textures in a CSG object that has union children, results are not as expected; instead, surfaces in the union children that have no explicit texture will be rendered with the default texture instead. This is not the case for e.g. difference children.
Example:
#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 }
#declare U = union {
sphere { <0,-0.1,-1>, 0.3 }
sphere { <0, 0.1,-1>, 0.3 pigment { color red 1 } }
}
intersection {
sphere { <0,0,0>, 1 pigment { color green 1 } }
object { U }
cutaway_textures
rotate y*90
}
When declaring U as an intersection instead, the results are as expected, with the surface of the first sphere in U being rendered with the texture defined in the outer intersection.
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286 | Texture/Material/Finish | Possible Bug | 3.70 RC7 | Very Low | Low | reflection exponent other than 1 causes black artifacts... | Tracked on GitHub | |
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Task Description
[EDIT: Original title was “radiosity causing black patches when using emission less than 0”]
see attached image for reference.
mountain on left has emission set to -.13 and black patches show up, when emmission set to 0 or greater no patches
changing max_trace or any radiosity settings has no effect
setting no_radiosity on mountain fixed problem as a temp fix
code sample ...
#version 3.7;
#default { finish { ambient 0 } }
#declare rad_lvl = 4;
global_settings {
assumed_gamma 1
max_trace_level max(5,rad_lvl*3)
adc_bailout .007
ambient_light 0
radiosity {
pretrace_start 64/max(image_width,image_height)
#if(rad_lvl)
pretrace_end max(2,int(8/rad_lvl))/max(image_width,image_height)
#else
pretrace_end 32/max(image_width,image_height)
#end
count pow(rad_lvl+1,2)*10
nearest_count 1
#if(rad_lvl) error_bound 1/rad_lvl #end
low_error_factor max(.4,(8-rad_lvl)/10)
recursion_limit 1
gray_threshold .25
brightness 1
max_sample 1
normal on
media off
always_sample off
minimum_reuse min(.008,8/max(image_width,image_height))
maximum_reuse .1
adc_bailout .02
}
}
#declare sunC = rgb <1, 1, .9925>; // actual D65 standard illuminant
#declare SkyC = rgb <.3195, .5745, .8805>;
#macro GammaAdj(C,G) rgb <pow(C.red,G),pow(C.green,G),pow(C.blue,G)> #end
light_source {
50000*y
sunC*1.06
area_light <-300, 0, -300>, <300, 100, 300>, 3, 3
rotate <-28, 0, 14>
adaptive 0
circular
}
sphere { 0, 1
texture {
pigment{
gradient y
pigment_map{
[.07 GammaAdj(SkyC,.5)]
[.2 average pigment_map { [.5 GammaAdj(SkyC,.75)][1 wrinkles turbulence .65 octaves 5 lambda 3 omega .9 color_map { [.2 rgb 1][.5 SkyC] } scale <10, .1, 1>] }]
[.4 GammaAdj(SkyC,1.15)]
[.5 GammaAdj(SkyC,1.35)]
}
rotate -75*y scale <1, 1, 100>
}
finish { diffuse .72 }
}
scale 100000
inverse
}
#declare Cam_pos = Cam_pos + <0, 20, -40>;
#declare Cam_lkt = Cam_lkt + <0, 10, 50>;
camera {
location Cam_pos
direction <0,0,1>
right 1.33*x
up y
sky <0,1,0>
#if(Cam_agl) angle Cam_agl #end
look_at Cam_lkt
}
#macro sinai(HillQ)
#local F = function { pattern { granite poly_wave 4 turbulence .01 lambda 2.1 omega .9 scale 5 translate <.2, 0, 18.08> scale <2, 1, 3> } }
#local N = function { pigment { crackle ramp_wave turbulence .3 lambda 2.2 omega .76 color_map {[0 rgb 0][1 rgb 1] } scale .07 translate <-.15, -.12, .13> } }
height_field {
function HillQ, HillQ { F(x,y,z) + N(x,y,z).grey/47 }
water_level .05
clipped_by { box { <0, .05, .3>, <1, 1, 1> } }
translate <-.5, -.05, -.5>
rotate 20*y
texture {
pigment{ crackle color_map { [0 rgb <161, 107, 71>/255][.25 rgb <193, 132, 93>/255][.35 rgb <218, 163, 123>/255][.45 rgb <212, 153, 112>/255][.55 rgb <222, 166, 125>/255][.65 rgb <236, 178, 124>/255][.75 rgb <220, 154, 102>/255][.85 rgb <160, 121, 103>/255] } turbulence .75 lambda 3 omega .7 scale .1 }
finish{ diffuse albedo .56 emission -.13 specular .25 roughness .02 brilliance 1.5 metallic 1.3 }
normal { crackle poly_wave .7 turbulence .4 omega .8 scale <.007, .03, .007> }
}
rotate 12*y
scale <2400, 2000, 3000>*1.5
translate <1900, 0, 1900>
scale <-1,1,1>
no_radiosity
}
#end
sinai(1600)
plane { y,0 pigment { rgb <1, 1, 1> } }
//courtyard gating not included due to size of code and many external files needed. add anything around <0,0,0> to try to reproduce effect of error
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7 | Radiosity | Unimp. Feature/TODO | 3.70 beta 32 | Low | Medium | Re-implement Radiosity render abort/continue support | Tracked on GitHub | |
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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.
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4 | Subsurface Scattering | Unimp. Feature/TODO | 3.70 beta 32 | Very Low | Low | Integrate Subsurface Scattering with standard lighting ... | Tracked on GitHub | |
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.
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6 | Subsurface Scattering | Unimp. Feature/TODO | 3.70 beta 32 | Defer | Low | Integrate Subsurface Scattering with Photons | Tracked on GitHub | |
Future release |
Task Description
Subsurface scattering must be made photon-aware.
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8 | Radiosity | Unimp. Feature/TODO | 3.70 beta 32 | Defer | Low | Improve Radiosity "Cross-Talk" Rejection in Corners | Tracked on GitHub | |
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.
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106 | Distribution | Unimp. Feature/TODO | 3.70 beta 37 | Very Low | Low | Update 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.
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205 | Documentation | Unimp. Feature/TODO | 3.70 RC3 | Very Low | Low | Syntax documentation uses inconsistent notation | Tracked on GitHub | |
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Task Description
The syntax notation used in the main documentation is different than that used in the quick-reference section. This should be changed for consistency, using the superior quick-reference notation throughout.
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