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
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>>
>>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.
>
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