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From: Warp
Subject: UV-mapping of bicubic patches not working in 0.6a
Date: 11 Nov 2000 07:35:42
Message: <3a0d3d1d@news.povray.org>
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This works fine with megapov 0.5a (the bicubic patch has a checker pigment
applied to it) but in megapov 0.6a the bicubic patch is just white:
camera { location -z*8 look_at 0 angle 35 }
light_source { -z*10, 1 }
bicubic_patch
{ type 1 flatness 0 u_steps 4 v_steps 4,
0, x, x*2, x*3,
y, x+y, x*2+y, x*3+y,
y*2, x+y*2, x*2+y*2, x*3+y*2,
y*3, x+y*3, x*2+y*3, x*3+y*3
uv_mapping
pigment { checker rgb x, rgb 1 scale .125 }
translate <-1.5,-1.5,0>
}
--
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/
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In article <3a0d3d1d@news.povray.org>, Warp <war### [at] tag povray org>
wrote:
> This works fine with megapov 0.5a (the bicubic patch has a checker
> pigment applied to it) but in megapov 0.6a the bicubic patch is
> just white:
UV-mapping of bicubic patches changed between the two versions. I think
it is explained under "8.6.4. Other changes related to UV mapping" in
the MegaPOV manual.
--
Christopher James Huff
Personal: chr### [at] mac com, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tag povray org, http://tag.povray.org/
<><
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From: MikeH
Subject: Re: UV-mapping of bicubic patches not working in 0.6a
Date: 11 Nov 2000 21:37:26
Message: <3A0DF3E3.FDFFC6B2@aol.com>
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> > This works fine with megapov 0.5a (the bicubic patch has a checker
> > pigment applied to it) but in megapov 0.6a the bicubic patch is
> > just white:
>
> UV-mapping of bicubic patches changed between the two versions. I think
> it is explained under "8.6.4. Other changes related to UV mapping" in
> the MegaPOV manual.
A change that was made in version 0.6a is that the uv_vectors need to be
specified AFTER the patch vectors and before the uv_mapping keyword.
Warp's example renders properly if specified as:
bicubic_patch
{
type 1
flatness 0
u_steps 4
v_steps 4,
0, x, x*2, x*3,
y, x+y, x*2+y, x*3+y,
y*2, x+y*2, x*2+y*2, x*3+y*2,
y*3, x+y*3, x*2+y*3, x*3+y*3
uv_vectors <0, 0>, <1, 0>, <1, 1>, <0, 1>
uv_mapping
pigment { checker rgb x, rgb 1 scale .125 }
translate <-1.5,-1.5,0>
}
But there is still a bug present, since it should render properly without
ANY uv_vectors specified. I'm not positive, but I think that when someone
moved the code:
MSquareQuad(Object->ST, Object->Mapping); /* mapping matrix */
in parse.c, it caused that section of the code to not execute unless
uv_vectors are specified with the patch. The result is that mapping
transform is not performed on the uv_vectors created with the patch by
default, and thus the texture is not mapped correctly. Again, not sure but
I think that's the problem.
-Mike
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From: Warp
Subject: Re: UV-mapping of bicubic patches not working in 0.6a
Date: 13 Nov 2000 09:30:19
Message: <3a0ffafb@news.povray.org>
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Yes, it would make sense that <0,0>,<1,0>,<1,1>,<0,1> would be the default
if none is specified.
--
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/
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