POV-Ray : Newsgroups : povray.windows : POV has Antialias against Background? Server Time
5 Jul 2024 04:53:00 EDT (-0400)
  POV has Antialias against Background? (Message 1 to 9 of 9)  
From: Bogdan
Subject: POV has Antialias against Background?
Date: 18 Jan 2001 20:39:30
Message: <3A679B14.EE62D419@yahoo.com>
Hi

I am new to POV world...but allready  like it very much

I have a problem: How to disable antialiasing against a background?
is it possible?

I need this because i am working at a RTS game...and we need to
eliminate black borderes around our sprites ....

Thx
Bogdan


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From: Ben Chambers
Subject: Re: POV has Antialias against Background?
Date: 18 Jan 2001 21:20:21
Message: <3A67A484.2AC35A41@hotmail.com>
Bogdan wrote:

> Hi
>
> I am new to POV world...but allready  like it very much
>
> I have a problem: How to disable antialiasing against a background?
> is it possible?
>
> I need this because i am working at a RTS game...and we need to
> eliminate black borderes around our sprites ....
>
> Thx
> Bogdan

If you're trying to eliminate the black border, it sounds like you
_want_ antialiasing.  Aliasing is the "sharp border" effect, which also
causes jagged lines.  Antialiasing softens borders, lines and colors in
such a way that these artifacts disappear.
...Chambers


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From: Bogdan
Subject: Re: POV has Antialias against Background?
Date: 18 Jan 2001 21:32:12
Message: <3A67A76D.574DEE40@yahoo.com>
Ben Chambers wrote:
> 
> Bogdan wrote:
> 
> > Hi
> >
> > I am new to POV world...but allready  like it very much
> >
> > I have a problem: How to disable antialiasing against a background?
> > is it possible?
> >
> > I need this because i am working at a RTS game...and we need to
> > eliminate black borderes around our sprites ....
> >
> > Thx
> > Bogdan
> 
> If you're trying to eliminate the black border, it sounds like you
> _want_ antialiasing.  Aliasing is the "sharp border" effect, which also
> causes jagged lines.  Antialiasing softens borders, lines and colors in
> such a way that these artifacts disappear.
> ...Chambers

Yes i know ...but you see:
When anti-alias is done some pixeles at the margin of the image (sprites
on black background) 
are "blended" betwwen my model and background....so when i place the
sprite in my game...(using color rgb<0,0,0> as a "color key", ie dont
place those pixels)
then a thin black border appeares on screen....its because of
antialias..hellas

I want antialias inside the sprite (model) just dont want it around the
model..or lets say
at the place "the ray" touches the background (a black one )

Such a feature is VERY much used in games...(3D Max has it...but i like
POV better :) )

Thx


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From: C J 
Subject: Re: POV has Antialias against Background?
Date: 19 Jan 2001 09:30:53
Message: <3a684f9d$1@news.povray.org>
Try raising the ambient value a little and render with the AA. This should
cut back on the blending in the trace. But it might make the image look more
"cartoonish".

Just a thought.

C.J. - POV User

"Bogdan" <bog### [at] yahoocom> wrote in message
news:3A679B14.EE62D419@yahoo.com...
> Hi
>
> I am new to POV world...but allready  like it very much
>
> I have a problem: How to disable antialiasing against a background?
> is it possible?
>
> I need this because i am working at a RTS game...and we need to
> eliminate black borderes around our sprites ....
>
> Thx
> Bogdan


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From: Peter Popov
Subject: Re: POV has Antialias against Background?
Date: 19 Jan 2001 12:00:53
Message: <mbog6t4v9u0vm3dbh9a5395ahpj41lvnom@4ax.com>
On Fri, 19 Jan 2001 04:33:17 +0200, Bogdan <bog### [at] yahoocom>
wrote:

>when i place the sprite in my game...(using color rgb<0,0,0> as a 
>"color key", ie dont place those pixels) then a thin black border 
>appeares on screen....its because of antialias..hellas

Use a function like the "Remove black matte" in PhotoShop. Either that
or soften your color_key (to remove some of the black on the edges)


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg


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From: Jim Kress
Subject: Re: POV has Antialias against Background?
Date: 19 Jan 2001 13:46:39
Message: <3a688b8f$1@news.povray.org>
From Paint Shop Pro help:

When you promote or paste a selection to create a layer, some of the pixels
surrounding the border are included, especially when it has been antialiased
or feathered. Matting cleans up the border by removing these pixels.


grey scale or 24-bit color image.

Removing Black and White Matte

When you promote a selection that contains white or black at its edges into
a layer, the edges of the layer now contain black and white pixels. If the
promoted layer is above a colored layer, the white or black needs to be
removed using the following method:





Defringing a Layer

Defringing bleeds non-feathered pixels in the layer edges outward and over
the "jaggies" in the feathered part of the selection. Use the Defringe
command when the background of a layer is a color (not black or white).

To defringe a layer:

1 Choose Layers > Matting > Defringe. The Defringe dialog box opens.

2 Enter the pixel width you want to defringe.

3 Click OK to close the dialog box defringe the layer.


Jim


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From: Remco de Korte
Subject: Re: POV has Antialias against Background?
Date: 19 Jan 2001 15:31:37
Message: <3A68A352.1EA323BC@onwijs.com>
I don't know if it's too much work but you could trace each image twice, one
with and one without AA and then use the second as mask. If you want to make it
real easy you can make everything in the second image white with ambient 1
against a black background. It works for me... 8)

Remco


Bogdan wrote:
> 
> Hi
> 
> I am new to POV world...but allready  like it very much
> 
> I have a problem: How to disable antialiasing against a background?
> is it possible?
> 
> I need this because i am working at a RTS game...and we need to
> eliminate black borderes around our sprites ....
> 
> Thx
> Bogdan


Post a reply to this message

From: User
Subject: Re: POV has Antialias against Background?
Date: 2 Apr 2001 08:31:18
Message: <3ac87116@news.povray.org>
"Bogdan" <bog### [at] yahoocom> skrev i meddelandet
news:3A679B14.EE62D419@yahoo.com...
> Hi
>
> I am new to POV world...but allready  like it very much
>
> I have a problem: How to disable antialiasing against a background?
> is it possible?
>
> I need this because i am working at a RTS game...and we need to
> eliminate black borderes around our sprites ....
>
> Thx
> Bogdan

Hi,

I would suggest the use of alpha map in this case, that way
you may use one image for several backgrounds.
It would also require you to use direct x or Open GL
for the best performance. Both are possible without too
much hassle in assembler (since you use that). Otherwise
you will end up with too many images and problems
due to differences in backgrounds. For example a flying
object that passes over numerous houses etc.
I would recommend OpenGL for this since it is much
easier to implement for you in this case. Just create
a surface, bind the texture (picture of the object) onto
that surface. Apply blending and you are in business ;-)

Good luck on your game.

Michael.T.


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From: Alan Kong
Subject: Re: POV has Antialias against Background?
Date: 2 Apr 2001 20:22:08
Message: <2q5icto6s9fvbge9b8pge6hvggn6sprdqb@4ax.com>
On Mon, 2 Apr 2001 14:32:19 +0200 User wrote:

>I would recommend OpenGL for this since it is much
>easier to implement for you in this case.

  Thanks for your advice, Michael, but it's possible that the person who
posted the original article may not look for your reply - this thread began
and ended January.

-- 
Alan - ako### [at] povrayorg - a k o n g <at> p o v r a y <dot> o r g
http://www.povray.org - Home of the Persistence of Vision Ray Tracer


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