Mail Archives: djgpp/2001/03/25/07:04:06
Message-ID: | <3ABDDBA9.B937780E@free.fr>
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From: | Kirill Pankratiev <kirill AT free DOT fr>
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Organization: | MICROWARE
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X-Mailer: | Mozilla 4.05 [en] (Win95; I)
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MIME-Version: | 1.0
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Newsgroups: | comp.os.msdos.djgpp
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Subject: | please help with Texture coordinates!
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Lines: | 29
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Date: | Sun, 25 Mar 2001 11:52:22 GMT
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NNTP-Posting-Host: | 213.228.19.109
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X-Trace: | nnrp1.proxad.net 985521142 213.228.19.109 (Sun, 25 Mar 2001 13:52:22 MEST)
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NNTP-Posting-Date: | Sun, 25 Mar 2001 13:52:22 MEST
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To: | djgpp AT delorie DOT com
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DJ-Gateway: | from newsgroup comp.os.msdos.djgpp
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Reply-To: | djgpp AT delorie DOT com
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Hello All!
I would like to know how to use texture coordinates for
perspective texture mapping.
So far i 've always used the 'magic vectors' to transform
points from screen space to texture space . ie
(u,v) = T * invP * invV *(Sx, Sy, 1)
where invV is the inverse viewport transformation and invP
is the inverse Projection and T is the "Magic matrix"
Here we suppose that texture coordinates are
(0,0) (1,0)
(0,1) (1,1)
What i want to do is to have U V associated with each vertex
so that i can start at say (0,5,0.5) and end at (0.8, 0.8 ) of the
texture
for exempla.
When i use linear interpolation it works but it gives very poor quality
because
it doesn' t take into account perspective deformation.
Can somebody please explain what i should do from the stage where i
project
the polygon?
Thanks.
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