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grunz
01-17-2004, 11:01 AM
Hi.
GLSL uses arb_fragment_shader and arb_vertex_shader.
So I could write my shader in GPU assembler and they would work also with newer generations of graphic cards?
Of course there are some limitations of GPU assembler but its mostly the same thing as I would write my shader in GLSL?
I ask this because nvidia doesn't have a GLSL support currently and I want also to support older cards like gf3 with some fallback arb_vertex_shaders.

Thanks

lc_overlord
01-17-2004, 01:30 PM
The problem with gpu assembler is that any shader you write may not work on other card's.
GLSL actuarly compiles to GPU assembler code when loaded, so in theory you should be able to run GLSL on allmost any GPU that support's pixel/vertex shader's.
So GLSL will work for most card's once there is driver support for it.
ATI and 3DLabs has some beta support for GLSL and Nvidia is expected to release GLSL support soon(perhaps they decided to release a better version than the other's).

Korval
01-17-2004, 06:05 PM
GLSL uses arb_fragment_shader and arb_vertex_shader.

No, it doesn't. Glslang does not compile to ARB_vp or ARB_fp code. It, instead, compiles directly to the hardware's internal code.

grunz
01-18-2004, 01:26 AM
thanks for your replies.
Is it also possible to support older cards like gf3 with a GLSL-fallback? Or do I will need to nvemulate.exe to the nv30?

Thanks

lc_overlord
01-18-2004, 03:16 AM
it should run just fine, perhap's somewhat less optimised than on a nv30.

Zengar
01-19-2004, 08:27 AM
It would run extremely SLOW because of many many FP instructions needed to be executed per-fragment. What are you talking about?

lc_overlord
01-20-2004, 03:30 AM
the actual speed largely depend's on the card and the complexity of your shader.
If you dissregard the effect that the actual speed of the card creates, some (simple)shader's may actuarly run allmost as fast on any geforce(3,4,FX) while other(most)ones will run faster.

Zengar
01-20-2004, 07:11 AM
I don't want to argue, but on my Athlon 2000+ 600x600 pixels using 20-30 instruction shader are rendered via emulator in about 1-2 seconds. With GFFX I get 70 FPS. I think there is a great difference.

lc_overlord
01-20-2004, 09:07 AM
there is a helluva difference between an emulator and a GFFX.