David Buck wrote:
[snip]
> 
> Discussion is welcome.
> 
Something that I think has not been mentioned in this discussion so far 
(unless I accidentally skipped it):
One of the interesting things of POV is that it is a great environment 
to learn maths. Often you want to position two objects in such a way 
that they touch each other or such that the combined surface is 
continuous or... You can do this by trial and error, but soon you'll end 
up motivated to learn how to solve a particular second order equation or 
some equation involving sin() or tan().
Whatever direction a new SDL is going to take, it would be great if the 
simplest subset could (still) be used in a high school math class. The 
only thing we then need is someone to write something like 'Mindstorms 
for high school students'.

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"Zeger Knaepen" <zeg### [at] povplacecom> wrote:
> I mean: as it is now, POV-SDL has a C-like syntax.  I think it would be a
> very bad idea to change the POV-SDL into a BASIC-like syntax, or a
> Python-like syntax

hey, how about pretty much no syntax at all?

(union (plane y (pigment (checker 0 1)))
         (sphere 0 1
                 (texture (pigment (rgb x))
                          (finish (phong 0.8 30)))))
(light-source white (* 5 #(-1 1 -1)))
(camera (z -3) 0)

well, except for Lots of Irritating Silly Parentheses, that is... :)

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Ger nous apporta ses lumieres en ce 2007/09/19 13:16:
> Zeger Knaepen wrote:
> 
> If vars are defined as float then why the need to define them as such? On
> the other hand, integers are much faster so why not use both?
>
Integer operations are not faster than floating point ones, this is due to the 
arithmetic coprocessor that is integrated in all processors since the advent of 
the Pentium. In fact, the oposite is almost always thrue for any multiplication, 
division and modulo. It was even the case for the 286, 386 and 486 whenever you 
also had an arithmetic coprocessor installed on your machine.

-- 
Alain
-------------------------------------------------
Don't cry because it is over, smile because it happened.

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nemesis nous apporta ses lumieres en ce 2007/09/19 17:10:
> "Zeger Knaepen" <zeg### [at] povplacecom> wrote:
>> I mean: as it is now, POV-SDL has a C-like syntax.  I think it would be a
>> very bad idea to change the POV-SDL into a BASIC-like syntax, or a
>> Python-like syntax
> 
> hey, how about pretty much no syntax at all?
> 
> (union (plane y (pigment (checker 0 1)))
>          (sphere 0 1
>                  (texture (pigment (rgb x))
>                           (finish (phong 0.8 30)))))
> (light-source white (* 5 #(-1 1 -1)))
> (camera (z -3) 0)
> 
> well, except for Lots of Irritating Silly Parentheses, that is... :)
> 
> 
> 
Makes me think of Lisp! TONS of parenteses ;-)

-- 
Alain
-------------------------------------------------
Experience hath shewn, that even under the best forms of government those
entrusted with power have, in time, and by slow operations, perverted it
into tyranny.
Thomas Jefferson

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Jim Henderson wrote:
> Seriously, though, I agree with this - if there's functionality to add to 
> SDL I'm all for that, but changing the format of things like object 
> definitions is going to require people relearn the language - if that's 
> going to happen, there ought to be a very good reason for doing so other 
> than "we wanted a different syntax".

I don't think it is necessary to change object definitions. That's not to
say there may not be another means to create them programmatically if you
happen to be generating a scene from an algorithm, but the basic definition
syntax for objects, cameras, etc, could reasonably stay the same.

As has been mentioned elsewhere in this thread, SDL is really two things: a
scene description language and a scripting language. It started with the
pure SDL and the scripting was added later. Therefore it's not unreasonable
 to suggest that scripting can be changed without changing the core object
syntax.

-- Chris

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>> Zeger Knaepen wrote:
>>
>> If vars are defined as float then why the need to define them as such? On
>> the other hand, integers are much faster so why not use both?
>>

actually, I didn't

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On Thu, 20 Sep 2007 08:05:22 +1000, Chris Cason wrote:

> I don't think it is necessary to change object definitions. That's not
> to say there may not be another means to create them programmatically if
> you happen to be generating a scene from an algorithm, but the basic
> definition syntax for objects, cameras, etc, could reasonably stay the
> same.
> 
> As has been mentioned elsewhere in this thread, SDL is really two
> things: a scene description language and a scripting language. It
> started with the pure SDL and the scripting was added later. Therefore
> it's not unreasonable
>  to suggest that scripting can be changed without changing the core
>  object
> syntax.

No argument from me on this. :-)

Jim

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In article <46f198c1$1@news.povray.org>, ele### [at] netscapenet 
says...
> Ger nous apporta ses lumieres en ce 2007/09/19 13:16:
> > Zeger Knaepen wrote:
> > 
> > If vars are defined as float then why the need to define them as such? 
On
> > the other hand, integers are much faster so why not use both?
> >
> Integer operations are not faster than floating point ones, this is due t
o the 
> arithmetic coprocessor that is integrated in all processors since the adv
ent of 
> the Pentium. In fact, the oposite is almost always thrue for any multipli
cation, 
> division and modulo. It was even the case for the 286, 386 and 486 whenev
er you 
> also had an arithmetic coprocessor installed on your machine.
> 
Tell that to the people that wrote Franctint (on a 486, Pentium or 
anything else). lol But seriously, even if they where marginally faster 
at one point, for specific situations, this isn't necessarily true now, 
nor applicable to what **this** program is doing. The results even in 
Fractint differed in some cases, depending on if you used the faster 
integers or floating point. One of the points of having POVRay behave as 
it does is "predictability" in what you get from it.

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}

<A HREF='http://www.daz3d.com/index.php?refid=16130551'>Get 3D Models,
 
3D Content, and 3D Software at DAZ3D!</A>

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Patrick Elliott nous apporta ses lumieres en ce 2007/09/19 23:13:
> In article <46f198c1$1@news.povray.org>, ele### [at] netscapenet 
> says...
>> Ger nous apporta ses lumieres en ce 2007/09/19 13:16:
>>> Zeger Knaepen wrote:
>>>
>>> If vars are defined as float then why the need to define them as such? On
>>> the other hand, integers are much faster so why not use both?
>>>
>> Integer operations are not faster than floating point ones, this is due to the 
>> arithmetic coprocessor that is integrated in all processors since the advent of 
>> the Pentium. In fact, the oposite is almost always thrue for any multiplication, 
>> division and modulo. It was even the case for the 286, 386 and 486 whenever you 
>> also had an arithmetic coprocessor installed on your machine.
>>
> Tell that to the people that wrote Franctint (on a 486, Pentium or 
> anything else). lol But seriously, even if they where marginally faster 
> at one point, for specific situations, this isn't necessarily true now, 
> nor applicable to what **this** program is doing. The results even in 
> Fractint differed in some cases, depending on if you used the faster 
> integers or floating point. One of the points of having POVRay behave as 
> it does is "predictability" in what you get from it.
> 
If using a 486 or earlier, AND NOT using an arithmetic coprocessor, integer 
operations where much faster than floating point. Especialy the add and 
substract. Multiplications where only slightly faster.
Add in the coprocessor and, apart from int add and sub, floating point jumps 
ahead, largely ahead!
At that time, you could get slightly different results depending on the brand of 
your coprocessor: differing algorythm and rounding method, as well as intrinsic 
precision.


-- 
Alain
-------------------------------------------------
You know you've been raytracing too long when you stop using a protractor to 
measure angles because you can do it just by looking.
Taps a.k.a. Tapio Vocadlo

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"Zeger Knaepen"  wrote in message <46f15701$1@news.povray.org>:
> I prefer the current syntax actually. All the commas after ] seem completely 
> redundant, the keyword scene is a nice idea if it would be possible to 
> define multiple scenes in one file, but it should be optional.
> The line "use Colors;" seems completely out of place for two reasons: first, 
> Colors what? Colors.inc ? Colors.pov ? ..? second, considering the rest of 
> the syntax, wouldn't something like "include [colors.inc,textures.inc]" be 
> more consistent?

I believe you somewhat missed my point. The sample code I just posted is not
just a random suggestion of syntax: it is perfectly valid Perl code: if
someone writes the few functions it uses, it will parse and run perfectly.

My point is to show that, although it is not possible to keep exactly the
same syntax as the current one, it is possible to use a real programming
language while keeping the syntactic noise very low.

And please note that a part of your remarks comes from habit rather than
real syntactic superiority.

The advantages of using a real programming language are obvious: the time of
PoV developers is better spent improving the rendering features than
reinventing support for data structures and control loops.

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