POV-Ray : Newsgroups : povray.documentation.inbuilt : Errors in light attenuation and height field documentation : Re: Errors in light attenuation and height field documentation Server Time
26 Jan 2022 12:48:04 EST (-0500)
  Re: Errors in light attenuation and height field documentation  
From: James Holsenback
Date: 24 Mar 2013 10:46:09
Message: <514f11b1$1@news.povray.org>
On 03/24/2013 10:25 AM, James Holsenback wrote:
> On 03/24/2013 02:01 AM, Cousin Ricky wrote:
>> I have found a couple of errors in the 3.7 documentation.
>>
>> At http://wiki.povray.org/content/Reference:Light_Source#Light_Fading
>> in the
>> wiki and in section 3.4.4.1.9 of the 3.7 off-line documentation, an
>> example
>> function is given to determine the brightness of a light source:
>>
>>    #declare Intensity_Factor = function (LD,FD,FP) {pow(1+(LD/FD),FP)/2};
>>
>> This should be:
>>
>>    #declare Intensity_Factor = function (LD,FD,FP) {(1+pow(LD/FD,FP))/2};
>
> Indeed I added (well ... plagiarized) it from a NG discussion, that I
> couldn't find to check if a mistake was made. I did however find and
> check my own personal notes from when was putting the entry together and
> it appears that I at least got it right. I couldn't comment of the
> correctness of the math. Care to elaborate? Oh ... IIRC Trevor Quayle
> was the author.
>
>> At http://wiki.povray.org/content/Reference:Height_Field in the wiki
>> and in
>> section 3.4.5.1.5 of the 3.7 off-line documentation, the syntax
>> statement for a
>> height field function reads:
>>
>>    HF_FUNCTION:
>>      function FieldResolution_X, FieldResolution_Y (
>> UserDefined_Function )
>>
>> The parentheses should be curly braces:
>>
>>    HF_FUNCTION:
>>      function FieldResolution_X, FieldResolution_Y {
>> UserDefined_Function }
>
> Hmmm ... OK good find, but for some reason your correction looked
> incomplete. RE: from the declarations above shouldn't it be:
>
> HF_FUNCTION:
>    function (FieldResolution_X, FieldResolution_Y) { UserDefined_Function }

LOL ... after further review I /think/ I got that wrong. One's a 
declaration, the other (doc example) is a call


Post a reply to this message

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.