Re: FW: XFree86 future

nico wrote:

>On Fri, 28 Mar 2003 17:08:35 +0100
>James Arthur <[email protected]> wrote:
>
>  
>
>>On Friday 28 March 2003 16:09, Marco Bubke wrote:
>>    
>>
>>>What do you mean by real time?
>>>      
>>>
>>I mean that sometimes texture data has to be sent to the card in the
>>middle of a frame. Obviously, the faster the bus, the faster that data
>>can be sent. when rendering a large environment, you can quite easily
>>fill up the texture memory, so you need to get rid of textures you
>>can't see and load in ones you can. Same with model data and so on,
>>especially if it involves a lot of animations.
>>
>>    
>>
>>>>Oh yeah, rendering to textures. That's another way to flood the
>>>>AGP bus.
>>>>        
>>>>
>>>Why. Thats stupid. If you render to texture you render to the memory
>>>of the card. Otherwise you could use glReadPixels. Maybe you
>>>should read the Überbuffer draft and Real Time Rendering.
>>>      
>>>
>>It depends what you want to do with it. Some feedback routines require
>>the rendering take place to a buffer, then it be sent back through the
>>bus to be processed, then send it back to the card to be rendered.
>>
>>    
>>
>
>Sure but, does all widget from Qt or GTK could be cached ?
>Or even images inside a web browser  (which need to scroll but don't
>change "often") ?
>

Quartz is rendering the windows to textures. And textures can have alpha 
channels. Yes, you can do that all as textures. That I mean by rendering 
to textures. It clould be very fast and the most modern cards have 
enough memory. You can do effects like color room transformation too etc.
Think of a texture as image which can mapped on geometry, for example a 
rectangle or trangles etc. Today cards (Geforce) can have textures which 
size don't must be a power of two. In OpenGlL you can do all the stuff 
Render is doing, but hardware accelerated.  :-)

>
>And what about svg rendering ? Does this kind of vector picture could
>save memorie bandwith ? Could SVG be rendered by current GPU or OpenGL ?
>(new sets of icons use them to use zoom feature.
>
There are SVG renderer in OpenGL.

If you want understand OpenGL read the OpenGL programming language and 
real time rendering. It's more about 2D is much easier than 3D.

Marco