Shader model 3 on ATI issues

vvvv beta question
1

Hi all

As mentioned in a previous panicked yell in the shoutbox,
vs3 and ps3 shaders dont draw on my new ATI 6770 graphics card.
Any idea of a reason for this?

simple test is clone Constant.fx, connect to grid and renderer
see a white quad
change the technique to vs_3_0 or ps_3_0
see the quad disappear

Is this the old incompatibility with ATI re-emerging? (i.e. an oversight in the recent implementation of ATI friendly shaders)
It’s likely something that can be smoothed out, and I’m certain that the hardware is capable.

Likely of importance is that i’m running on beta26 with the new choice of shader compiler.
Can’t test the machine with <26 now as it’s in the middle of an install.

p.s. feel free to change thread type from question to bug if we can identify that it’s something to be fixed within vvvv .

Elliot

2

while patching with an ati eyefinity we had to change the order of the texCoord inside some shaders (dottores particlesGPU_2d_surfaces e.g.)

for nvidia cards it is working with randomly used tex coord0, tex coord2, …

with the ati it was only running with
texCoord0,
texCoord1
texCoord2

if there was a gap like

texCoord0;
texCoord2;
texCoord3;
…

it shows an error message

otherwise all shaders are working with beta26 (even vs_3_0 ; ps_3_0)

3

thanks for the details hrovac.

You clearly point out that it is possible to write a shader that will run on NVidia but will not run on ATI.
Obviously we need some more clarification with this, preferably with not only empirical results, but a definition of what is supported differently on the 2 manufacturers’ platforms.

I will test on beta25 and report if results differ from previous negative results on 26/6770/vs,ps3

4

bump bump!!

again i’m left cold with no texture lookup in shader because there’s no VS3 support on ATI cards in VVVV

is there a proper way to make support requests about issues like these?

5

Hi
dunno if it is of any help, but a few days ago while patching with @Lasal on ATI 6950 we ve foud out that some shader may or may not work if some render pass is on dda 0 while final renderer is in dda 1. I haven t got a clear explanation but things worked out at the end.
Have you tried to just launch the shader out of the patch context with a minimum setup as possible?
I am using a lot of VS3/PS3 shaders now wit the ATI and all works fine, even the GPU particles.
S.

6

hm, i rather doubt this is a vvvv issue.

  • does it work on b25.1 but not on b26?
  • when it doesn’t work is there an error?
  • the new compiler seems to be more picky, but i am not aware of any general incompatibilities.
7

Hi, Elliot. I’m usually compiling to PS3 and VS3 for ATI cards and all works fine. For example, i recently tested SplinesGPU on ATI and it’s currently works only with PS/VS 3.

8

basically what alg said. for ati/amd you should always set same shader version in VS and PS.

also happy bday, alg! ;)

9

@alg - thanks so much. working now with matching version numbers
happy birthday man!

10

thx guys )