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POV 3.5 b 9.icl on PII 233 128 MB with NT 4 Sp 6
documentation says about spline specification
#declare IDENTIFIER =spline { [SPLINE_IDENTIFIER] [SPLINE_TYPE] ...
So identifier and type are both optional but can be together.
I checked that when spline S1 is declared and I declare spline S2 as "child" of
S1 but with different type then type declaration is parsed ok but do nothing.
But is is parsed ok so I don't know what is wrong parser, documentation or
engine. Conversion is definetly possible becouse when I force type in spline
calculation instead of definition then it is changed ok.
Below is test scene. Working with it I noticed another bug. I can't pass spline
calculation as macro parameter. To check it uncomment debug line. Works fine
when there is parenthesis around spline in call of VStr().
Playing with it I found also small feature request. I'll send it to p.general.
#version 3.5;
#include "stdinc"
global_settings {
assumed_gamma 1.0
}
camera {
location <0,.5,-4>
direction 1.5*z
right x*image_width/image_height
look_at 0
}
light_source {30*<-1,1,-1> color rgb 1}
background{1}
#declare Points=10;
#declare Radius=.1;
#declare Step=.1;
#macro Force()
#if(force_cubic)
,cubic_spline
#end
#end
#macro Draw(Spline,T,force_cubic) // let's draw spline
union{
#local c=1;
#while (c<=(Points-Step))
// #debug concat(Str(c)," - ",VStr(Spline(c)),"\n")
sphere{Spline(c Force()) Radius}
cylinder{Spline(c Force()),Spline(c+Step Force()),Radius}
#local c=c+Step;
#end
sphere{Spline(Points Force()) Radius}
pigment{color rgb 1}
scale .2
translate T*<.7,.5,1>
}
#end
#macro List() // makes list of points for spline
#local G=seed(0);
#local c=1;
#while (c<=Points)
c,2*<rand(G),rand(G),rand(G)>-1
#local c=c+1;
#end
#end
#local S1=spline{linear_spline List()} // works as expected
#local S2=spline{cubic_spline List()} // works as expected
#local S1a=spline{S1 cubic_spline List()} // type do nothing
#local S2a=spline{S2 linear_spline List()} // type do nothing
#local S1b=spline{S1 cubic_spline } // type do nothing
#local S2b=spline{S2 linear_spline} // type do nothing
#local S1c=spline{S1 3,2*y} // works as expected
#local S2c=spline{S2 3,2*y} // works as expected
Draw( S1 ,-2*x+y , no )
Draw( S2 ,-2*x-y , no )
Draw( S1a , -x+y , no )
Draw( S2a , -x-y , no )
Draw( S1b , 0+y , no )
Draw( S2b , 0-y , no )
Draw( S1c , x+y , no )
Draw( S2c , x-y , no )
Draw( S1c , 2*x+y , yes)
Draw( S2c , 2*x-y , yes)
// ABX
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wrote:
> documentation says about spline specification
>
> #declare IDENTIFIER =spline { [SPLINE_IDENTIFIER] [SPLINE_TYPE] ...
>
> So identifier and type are both optional but can be together.
>
The way I interpreted the changing of the spline type is that is is only
possible when you retreive one value from the spline.
#declare P1=<0,0,0>+Spline(1,linear_spline);
Not for copying a spline. I agree that in that case the syntax section
is not clear, is adding a pipe enough:
#declare IDENTIFIER =
spline {
[SPLINE_IDENTIFIER] |
[SPLINE_TYPE]
...
Then again, the current spline implementation is marked experimental and
has several bugs, so I'm not sure how it should/will work and what to
change in the docs. I'll put your remark in the todo list and wait for a
more final spline before changing the docs.
Ingo
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>documentation says about spline specification
>
>#declare IDENTIFIER =spline { [SPLINE_IDENTIFIER] [SPLINE_TYPE] ...
>
>So identifier and type are both optional but can be together.
>
>I checked that when spline S1 is declared and I declare spline S2 as
"child" of
>S1 but with different type then type declaration is parsed ok but do
nothing.
>But is is parsed ok so I don't know what is wrong parser, documentation or
>engine. Conversion is definetly possible becouse when I force type in
spline
>calculation instead of definition then it is changed ok.
>Below is test scene.
This should work, and doesn't. For those of you who are working on the
official source code, the fix is the following changes to Parse_Spline in
express.cpp:
Replace
EXPECT/*Check for spline identifier*/
CASE(SPLINE_ID_TOKEN)
New = Copy_Spline((SPLINE *)Token.Data);
i = New->Number_Of_Entries;
EXIT
END_CASE
OTHERWISE
UNGET
EXIT
END_CASE
END_EXPECT
with
EXPECT/*Check for spline identifier*/
CASE(SPLINE_ID_TOKEN)
New = Copy_Spline((SPLINE *)Token.Data);
i = New->Number_Of_Entries;
Type = New->Type;
EXIT
END_CASE
OTHERWISE
UNGET
EXIT
END_CASE
END_EXPECT
and add
New->Type = Type;
just before the line
return New;
>Working with it I noticed another bug. I can't pass spline
>calculation as macro parameter. To check it uncomment debug line. Works
fine
>when there is parenthesis around spline in call of VStr().
This is a known problem. I'm fairly sure it is officially classified as a
"feature", and putting parentheses around the spline is the recommended
work-around.
--
Mark
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