POV-Ray

Adjusting the brightness of an image-mapped sky sphere, although not an uncommon task especially when using HDR light probes, currently is cumbersome at best, as it is not possible to specify a “finish { ambient ... }” statement.

To simplify tuning a sky sphere’s brightness, I suggest introducing a “brightness FLOAT” modifier (defaulting to 1.0) to either the sky_sphere block or (as a more versatile solution) the image_map statement.

Input image files may have been created with gamma pre-correction for some specific target gamma, which may vary from image to image. Some file formats like PNG or HDR support embedding gamma pre-correction information in the image file, but this information may be missing or faulty, and some formats don’t support it at all. Additionally, it may be desirable to tamper with an input image’s gamma for artistic reasons.

Therefore, I suggest adding a means to explicitly specify input images’ originally intended target gamma on a per-image basis, like:

image_map { jpeg "MyImage.jpg" assumed_gamma 1.8 }

3.6x only bug with easy/known fix. Error message: “Identifier expected, incomplete function call or spline call found instead.” caused by token counter variable using the wrong special value. The symptom occurs when using a lot of splines. See this thread for details.

(I am using a self-compiled special build because I use a lot of splines in 3.6 but would rather use an official 3.6)

For some particularly “heavy” SDL scripts, it might be desirable to override (or complement) the standard “Parsing 47110815K tokens” progress information with some more helpful custom info, e.g. “Planting trees... (37%)”, or “Generating terrain mesh row 47 of 500”.

The parser is missing extra period characters when it parses a float as a vector component.

#local sample = <0.0.0.1,0,0>;

Doesn’t generate an error, but should.

The following (bogus) SDL code causes POV-Ray 3.7 beta to crash hard with an access violation:

#include "fubar.inc"
Bar(42)
#macro FooBar() #end

//fubar.inc
#macro Foo(Fnord) #end
#macro Bar(Ignord) Foo(23 #end

The parser does not accept mesh objects (or CSG objects including a mesh object) as a parameter to the inside() built-in function, reporting error “Solid object identifier expected”, even if the mesh is “solidified” by specifying an inside_vector.

(see news://news.povray.org:119/4a983716@news.povray.org)

Reported by cshake + pov @ gmail . com in p.beta-test, 14th december 2009

I wrote a simple script to convert fractint color maps to povray color_maps so I could use ApoMap to make nice fractal colors for pov, but I ran into
“Parse Error: Blend_Map too long.” The map has entries from 0/255 up to 255/255 (inclusive). I looked up the documentation which says that color_maps can have from 2 to 256 entries, and this is exactly 256 entries.
I’m posting this in beta-test because I assume that the documentation is correct for v3.6, and that a previous version can handle 256 entries.

The following SDL code

sphere {0, 1 pigment {image_map {png "missing.png"}}

yields “render failed” in 3.7b25 and the position of the error
is not highlighted in source code, giving no clue what went wrong.
In 3.6 this yields “Parse Error: Cannot open PNG file”.

Many people clearly miss a simple for-loop construct in povray. It is indeed true that probably at least 99% of #while loops out there have the form of a simple for-loop. It’s much rarer to have to use more exotic forms of looping supported by the #while mechanism. Thus it would make sense if a #for construct would be added which would make writing such loops much easier and convenient.

The only remaining question would be the syntax.

IMO the for-loop construct should implicitly declare a local variable of a specified name, automatically increment it during the loop, and then undefine it after the loop ends. It could perhaps be something along the lines of:

#for(<identifier name>, <initial value>, <final value> [, <step>])
  <loop body>
#end

Example:

#for(Counter, 1, 10) // 'Counter' gets values 1, 2, 3, ..., 10
  #debug concat(str(Counter, 0, 0), "\n")
#end
#for(Counter, 1, 10, 3) // 'Counter' gets values 1, 4, 7, 10
  #debug concat(str(Counter, 0, 0), "\n")
#end

I think this syntax ought to be relatively easy to implement (compared to more “traditional” syntaxes, such as something like “for Counter = 1 to 10” or the C syntax, which would be a lot more complicated).

Of course this raises a couple of questions:

1) What happens if ‘Counter’ was already declared as an identifier? One of three possibilities comes to mind:

• The ‘Counter’ in the for-loop replaces the previous identifier, as a regular #local command would.

• The ‘Counter’ in the for-loop hides the identifier for the duration of the loop, and unhides it afterwards.

• A syntax error is given (ie. the identifier name must be unused).

2) Should the user be able to modify the counter variable from inside the body of the loop? Something like this comes to mind as viable:

// Prints the values 1, 2, 3, 9 and 10
#for(Counter, 1, 10)
  #debug concat(str(Counter, 0, 0), "\n")
  #if(Counter = 3) #local Counter = 8; #end
#end

Alternatively the counter variable could be read-only.

Additionally, it could be nice if #break could be used to immediately jump out of the current loop (either #while or #for).

The following code is erroneously accepted by POV-Ray (tested with 3.7.0.beta.36):

pigment{
  slope { x }
  checker
}

The result is a checker pattern.

Apparently there is an EXIT statement missing in the slope-pattern parsing code in parstxtr.cpp.

The #switch directive isn’t parsing correctly. In the following construct NO warning or error is generated:

#switch (RF)

case (0)
	rotate z*355
#break
case (144)
	rotate z*7.5
#break
case (216)
	rotate z*5
#break

#end

RF is a variable passed to the macro in which this construct resides. The first ‘case’ action IS executed, but none of the others are on successive calls to the macro. If I properly add ‘#’ to the second case the 1st and 2nd condition are executed but not the last. If ‘#’ is REMOVED from any of the break directives an error is generated and parsing halts.

I can no longer run a Myfile.ini over a network, on a different computer.

Possiblely related to:

    http://bugs.povray.org/task/97   FS#97  (Forward-slash pathnames not fully supported in Windows version)

-
Cannot open INI file
‘\\STEPHEN-POVRAY\Bishop3d\Objects\Industrial_enclosure\Telco_enclosure_extra.ini’.
Failed to start render: Failed to parse INI file

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.

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.

Using the concat function is tedious. Why not just have an operator with which to concatenate strings?

“Hello " + “world!”

“Hello " . “world!”

Macros are finicky about how you type your code. What works outside macros sometimes fails inside them. For more information see the threads:

“Problems with macro (3.6)”, in p.a-u, 06-09-10
“Bad operands”, in p.g, 05-20-10

Still not sure *what* exactly the problem was, but one of my workarounds ended up working.

Currently, cameras placed inside object or union statements will halt the render with an error. Take for instance the following case:

#local temp_camera_1 = camera
{
  orthographic
  location  z*-12
  direction  z
  up    y
  right    x*image_width/image_height
  scale    32
}

#local temp_light_1 = light_source
{
  0
  color rgb 1
  translate <-30, 30, -30>
}

#local temp_light_2 = light_source
{
  0
  color rgb 1
  translate <-30, 30, +30>
}

union
{
  object {temp_light_1}
  object {temp_light_2}
//  camera {temp_camera_1}  // doesn't work!!!
}

//object {temp_camera_1}  // doesn't work!!!
camera {temp_camera_1}  // works!!!

Changing this behavior would make it possible to more easily apply transformations to scene objects and the camera at the same time in situations where the scene’s frame of reference is in motion relative to the rest of the scene, for instance in animations.

no warning is issued when an object/primitive has no pigment type given

I used POV-Ray to make an animation of my Morgan driving around a slalom course. (If you are curious, you can see the output on youtube under my user name, nojonushi.) To make the long swooping fenders I used Mike William’s SweepSpline macro.

The code rendered the 1189 frames in one go with no problems. But the wheels in that animation do not rotate, so I then added code to rotate the wheels. In the calculations I added I used a #while loop to step through the spline containing the route coordinates and total up the distance traveled. Running POV-Ray on this file produced a random number of images and then issued an error, e.g.

 0:00:00 Processing Frame 456 of 1189
 0:00:00 Parsing

File: mogslalom.pov Line: 1918
Parse Warning: Patch objects not allowed in intersection.
File: mogslalom.pov Line: 2988
File Context (5 lines):

                object {
                SweepSpline(TFSpline,

Parse Error: Identifier expected, incomplete function call or spline call found instead.

Most of the parameters for the macro are missing. But this is after successfully generating, in this case, 455 images.

I have attached a text file with set-up and sample code that has given the error on two different machines.

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 +Imesh_camera.pov +Omesh_camera.png +FN +W800 +H600 produces a “Failed to parse command-line option” error. when I rename my pov source file to ess_mesh_camera.pov it runs fine. seems to be pointing to a clash with the +im option. i also had another file that renaming it got me going.

Given the following two statements, a missing closing brace in the function declaration fn should throw a parse exception; instead it causes a memory access violation when trying to use fn in the second delcaration:

#local fn = function { 
  pigment { image_map { png "MultiPassBlobs3.png" gamma 1 map_type 0 once }} 
#local clr = fn(0,0,0);

original posting from povray.beta-test:

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

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

#version 3.7;

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

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

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

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

[...]

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

#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.

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

#local bar = A();

This causes either a segfault, corruption detected by malloc, or “Parse Error: Unknown user defined function”.

After some debugging I think this is what happens.

In source/backend/parser/parse.cpp, Parser::Parse_RValue is called to define the value of bar. Get_Token is called, which invokes A() and which ultimately returns foo as a FUNCT_ID_TOKEN. This token is handled by CASE_VECTOR in Parse_RValue. The relevant clause calls Parse_Unknown_Vector to parse additional tokens (e.g. “foo ( 1 )”). There aren’t any other tokens, but in the process of determining that, #end is reached and Return_From_Macro destroys the symbol table of A, including foo.

So by the time the CASE_VECTOR clause decides that foo is a function identifier that should be copied, the function is destroyed (both the function itself and its number in the symbol table). So here:

    Temp_Data  = (void *) Copy_Identifier((void *)*Token.DataPtr,*Token.NumberPtr);

if *Token.DataPtr (in this case, a function index) was already overwritten, we get “Unknown user defined function”; if it still has the valid function number, it increments the reference count of the function (which has already been freed) back from 0, and we get a double-free later.

A similar problem occurs when foo is a spline.

A tentative patch for the function case is attached.