As far as I know the problem with doing rasters as textures is that textures must have size that is a power of 2. It means that actual picture will have to be scaled and therefore will be imperfect, filtered or not. However, the purpose of raster is to look exactly the same as the original picture - which is not usually important for textures. So textured quads maybe ok to output text, but they can't be good to represent, say, background geometry. If textured quads are used as rasters in Direct3D, are they fuzzy (if filtered) or missing points (if not filtered), or Direct3D has some way of displaying textures perfectly?
- Yuri
-----Original Message-----
From: Doug Twilleager [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, June 12, 2001 7:27 PM
To: [EMAIL PROTECTED]
Subject: Re: [JAVA3D] Question on Rasters
Also note that until very recently, most consumer level cards did not
optimize glDrawPixels very well. So using a texture mapped quad is
still currently the most reliable method to do overlays.
Doug Twilleager
Java 3D Team
Sun Microsystems
>Delivered-To: [EMAIL PROTECTED]
>MIME-Version: 1.0
>Content-MD5: PZLkDfzWMpuo1/PGNocB2A==
>Subject: Re: [JAVA3D] Question on Rasters
>Comments: To: [EMAIL PROTECTED]
>To: [EMAIL PROTECTED]
>
>Hi David,
>
>>From: "David Yazel" <[EMAIL PROTECTED]>
>>To: "Kelvin Chung" <[EMAIL PROTECTED]>
>>Subject: Question on Rasters
>>Date: Tue, 12 Jun 2001 19:09:05 -0400
>>MIME-Version: 1.0
>>Content-Transfer-Encoding: 7bit
>>X-Priority: 3
>>X-MSMail-Priority: Normal
>>X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200
>>
>>Kelvin:
>>
>>I was wondering if you could take a second and explain what a raster is and
>>how it is implemented on your side in DirectX and OpenGL? What is it
>>designed for? I got a hint when I read that it was not pickable and assumed
>>that it is not really 3d and not sent to the card, but BLTTED onto the back
>>buffer before swap, but that is just a guess. If it is a 3d object then
>>does it use texture memory? do you map it to quads? I am seeing very good
>>results from texture mapped quads for overlays, but want to make sure I am
>>going in the right direction before proceeding further.
>>
>>
>OGL: Raster is implement as glDrawPixels()
> So the whole raster is pass down to the native code every frame.
>D3D: Don't have API similar to glDrawPixels(), so
> raster is implement as texture and map it to two triangles (no
> Quad support in D3D)
> Only when the raster change will the texture send down to the
> native code again.
>
>So if raster change every frame, OGL approach is faster, otherwise
>D3D approach should be faster.
>
>
>- Kelvin
>---------------
>Java 3D Team
>Sun Microsystems Inc.
>
>===========================================================================
>To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
>of the message "signoff JAVA3D-INTEREST". For general help, send email to
>[EMAIL PROTECTED] and include in the body of the message "help".
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff JAVA3D-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
