Re: RGB -> RGBA

New Message Reply Date view Thread view Subject view Author view

Greg Edwards (gedwards++at++cordoba.reading.sgi.com)
Wed, 22 Mar 1995 18:19:10 +0000

You can do all this with Paul Haeberli's old image tools, all the stuff
in ~4Dgifts/.../imgtools.
Eg. oneband separates images into separate R,G,B,A parts
     cglue joins them together again
     conimg make an image with a constant colour (eg. to be the alpha
                   plane).
     saturate you could use this to drive the tree to black and white to
                   make the alphe tree outline.

and many others. See ~4Dgifts/.../imgtools/README, you can do amazing things
with these simple tools.

Greg E.

On Mar 22, 8:35am, Kent Watsen wrote:
> Subject: Re: RGB -> RGBA
>
> >
> >
> > I want to reuse some old textures I have, but I want to add an alpha
> > bitplane. Is there any simple program where you can extract a
> > selected part of an image and set all pixels outside to have alpha
> > value, say eq. 50% ? For example: I want to make a tree (much like in
> > the Performer town) and I have a RGB texture of a tree, how to I set
> > the pixels outside the three to have an alpha value that makes them
> > invisible.
> >
> > Any ideas ?
> >
>
> There are some packages which can handle this, but they are rather
> expensive. I wrote some code which accepts two files, the first is
> the source image and the second is the ALPHA intensity image, and
> combinds them to form the needed RGBA image. I could make these
> conversion routines available if interested.
>
> Kent Watsen
> watsen++at++netcom.com
>
>
>
>
>-- End of excerpt from Kent Watsen

-- 
__________________________________________________________________________
Greg Edwards, Training & Consultancy Group, Silicon Graphics UK Ltd.        
1530 Arlington Business Park, Theale, Reading, UK, RG7 4SB. 
switch +44 1734 257500, direct +44 1734 257740, fax +44 1734 257553
gedwards++at++reading.sgi.com, US vmail 59130, UK vmail 7740#, mailstop IUK-311

New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:51:06 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.