PDA

View Full Version : can a vertex shader bypass the miniport settings?



Tzupy
09-24-2002, 11:05 AM
Hi, I'm porting an app display to OpenGL, and
have a dilemma. Basically I'm rendering antialiased line and quad strips. My card is
a GeForce2Ti and am also using a driver that was patched by SoftQuadro (in the miniport) to work like a Quadro (hardware accelerated antialiased line and quad strips).
I would like to upgrade to a GeForce4Ti but
the driver tweaking wouldn't work anymore.
Could a vertex or pixel shader program
achieve a similar antialiasing effect on a
GeForce4 as the standard antialiasing on a Quadro (that costs 600+ USD)?
Competent opinions are welcome. Thank you.

vshader
09-24-2002, 10:58 PM
you can't do antialiasing in a pixel shader because they only do one fragment at a time and know nothing about their neighbours.

when the NV30 comes out, you could maybe do something in a fragment program using the derivative instructions, but i'm not really sure. anyway, no way to do it for gf3/4

depending on what you need, you could try FSAA - it will antialias all your primitives for you.

or try drawing your lines as textured quads - the texture filtering will give you a smooth antialiased line effect (use trilinear filtering)

Tzupy
09-25-2002, 11:36 AM
Thanks VSHADER for your reply. I already use FSAA forced from the display settings, but it's not really helpful when I'm using the standard (not patched) Nvidia driver. The quad strips with SMOOTH and NICEST are rendering dead-slow with the standard driver, and still don't have the quality of the hardware rendering, which is also fast:
2-5 times faster than the equivalent GDI calls. It's such a shame that Quadro4 boards cost 2-2.5 times a Geforce4. Your second suggestion of using textured quads and filtering might work, I'll try it soon.